Con Rod Science

Chuck, I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest. I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine. I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
Later.

: Chuck,
: I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: Later.

MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : Chuck,
: : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : Later.

: MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. Later.

: : : Chuck,
: : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : Later.

: : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : Later.
I read an article in Hot Rod called "the 350
chevy should have built". I will try to find the
article so I can get my facts straight, but here
was the jist of it. the started with a 400 block
and put the longest rod/shortest piston comb.
the could find. it was a 4.125 bore and the stroke was such that it came out to 352 cubes.
it made over 400 hp on 87 octane gas with medeocre heads and a stock style cam. when I dig out the article I will give more detailed specs. This makes me agree with MM that a longer rod is better.

: : : Chuck,
: : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : Later.

: : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : Later.

I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : Chuck,
: : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : Later.

: : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : Later.

: I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

Chuck, Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
They are reasonably priced. good luck.

: : : : : Chuck,
: : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : Later.

: : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : Later.

: : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: Chuck,
: Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: They are reasonably priced. good luck.

: : : : : : Chuck,
: : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : Later.

: : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : Later.

: : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : Chuck,
: : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : They are reasonably priced. good luck.

: : : : : : : Chuck,
: : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : Later.

: : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : Later.

: : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : Chuck,
: : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : They are reasonably priced. good luck.

In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : : : : :Hoosier Regrinding
: : : 1462 Ash,St.
: : : Terre Haute,IN 47804
: : : 1-812-234-1715
: : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : John,
: : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : Chuck,
: : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : Later.

: : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : Later.

: : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : Chuck,
: : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : They are reasonably priced. good luck.

: In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : :Hoosier Regrinding
: : : : 1462 Ash,St.
: : : : Terre Haute,IN 47804
: : : : 1-812-234-1715
: : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : John,
: : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : Chuck,
: : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : Later.

: : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : Later.

: : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : Chuck,
: : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : They are reasonably priced. good luck.

: : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

Folks, : We have to start with the understanding that Californians said many years ago, " There's no replacement for displacement." Rod ratio is nice but it is not better than displacement. Naturally the ideal thing is to have alot of cubic inches with a good rod ratio. I would not sacrifice 1" of stroke and a bunch of cubic inches to get a great rod ratio.
: I looked a the comparison of short and long rod last weekend. The best result for the long rods is when they are on restrictive heads. I believe the old MM heads are less than ideal. The ideal
: set up probably wind up illegal to the NATPA, G-crank stroked to 7.4", 800 HD blocks w/ 3406 cat or Arias pistons, and Long of connecting rod as would fit!!

: : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : :Hoosier Regrinding
: : : : : 1462 Ash,St.
: : : : : Terre Haute,IN 47804
: : : : : 1-812-234-1715
: : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : John,
: : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : Chuck,
: : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : Later.

: : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : Later.

: : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : Chuck,
: : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : They are reasonably priced. good luck.

: : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : :Hoosier Regrinding
: : : : : 1462 Ash,St.
: : : : : Terre Haute,IN 47804
: : : : : 1-812-234-1715
: : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : John,
: : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : Chuck,
: : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : Later.

: : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : Later.

: : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : Chuck,
: : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : They are reasonably priced. good luck.

: : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : 1462 Ash,St.
: : : : : : Terre Haute,IN 47804
: : : : : : 1-812-234-1715
: : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : John,
: : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : Chuck,
: : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : Later.

: : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : Later.

: : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : Chuck,
: : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : They are reasonably priced. good luck.

: : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : 1462 Ash,St.
: : : : : : : Terre Haute,IN 47804
: : : : : : : 1-812-234-1715
: : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : John,
: : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : Chuck,
: : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : Later.

: : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : Later.

: : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : Chuck,
: : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : They are reasonably priced. good luck.

: : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

: : : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : : 1462 Ash,St.
: : : : : : : : Terre Haute,IN 47804
: : : : : : : : 1-812-234-1715
: : : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : : : John,
: : : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : : Later.

: : : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : : Later.

: : : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : : Chuck,
: : : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : : They are reasonably priced. good luck.

: : : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

Chuck, I think we are looking a basically the same facts. Where we differ is you want to take a long rod motor, "A moline" and make it a short rod engine. A G-226 allis is a fine engine for what it is. I think you will agree it is short lived when compared to a MM though. It's torque at 1100 rpm would be little to a 403 too. Even with well motor heads, best offered.the breathing of a MM is restrictive. 125 ci is hard to feed with a 1.5" valve. The long rod is necessary to let the piston dwell at BDC, botom dead center. If you have read Smokey Yunick on long rods you would know what I mean. The gain with long rods is the most with restrictive heads. Put he longest rod in the SOB and win races, or tractor pulls!!

: : : : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : : : 1462 Ash,St.
: : : : : : : : : Terre Haute,IN 47804
: : : : : : : : : 1-812-234-1715
: : : : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : : : : : John,
: : : : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : : : Later.

: : : : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : : : Chuck,
: : : : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : : : They are reasonably priced. good luck.

: : : : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : : : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: : I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

: Chuck,
: I think we are looking a basically the same facts. Where we differ is you want to take a long rod motor, "A moline" and make it a short rod engine. A G-226 allis is a fine engine for what it is. I think you will agree it is short lived when compared to a MM though. It's torque at 1100 rpm would be little to a 403 too. : Even with well motor heads, best offered.the breathing of a MM is restrictive. 125 ci is hard to feed with a 1.5" valve. The long rod is necessary to let the piston dwell at BDC, botom dead center. If you have read Smokey Yunick on long rods you would know what I mean. The gain with long rods is the most with restrictive heads. : Put he longest rod in the SOB and win races, or tractor pulls!!

Ihave been following this discussion for quite sometime with some interest,wondering if I should join in. I have been involved with engines for the last couple of decades even though I'm not a professional builder,I have done quite a bit of reading on the subject. According to some of the articles I've read,an engine with a long rod will give you a broader rpm range to make more torque. period! As long as you are running at Daytona!! Most short track engines,such as sprint cars, run a shorter rod ratio for faster acceleration out of the turns. A shorter rod will make more torque at low-mid engine rpms. In case you would like to reference any of this, a magazine called Chrysler Engines Etc. wrote a very nice article on the research that Chrysler did back in the 1950's. Maybe Smokey didn't pass along all of his secrets.

: : : : : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : : : : 1462 Ash,St.
: : : : : : : : : : Terre Haute,IN 47804
: : : : : : : : : : 1-812-234-1715
: : : : : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : : : : : : : John,
: : : : : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : : : : Later.

: : : : : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : : : : Chuck,
: : : : : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : : : : They are reasonably priced. good luck.

: : : : : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : : While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : : : : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: : : I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

: : Chuck,
: : I think we are looking a basically the same facts. Where we differ is you want to take a long rod motor, "A moline" and make it a short rod engine. A G-226 allis is a fine engine for what it is. I think you will agree it is short lived when compared to a MM though. It's torque at 1100 rpm would be little to a 403 too. : : Even with well motor heads, best offered.the breathing of a MM is restrictive. 125 ci is hard to feed with a 1.5" valve. The long rod is necessary to let the piston dwell at BDC, botom dead center. If you have read Smokey Yunick on long rods you would know what I mean. The gain with long rods is the most with restrictive heads. : : Put he longest rod in the SOB and win races, or tractor pulls!!

: Ihave been following this discussion for quite sometime with some interest,wondering if I should join in. I have been involved with engines for the last couple of decades even though I'm not a professional builder,I have done quite a bit of reading on the subject. According to some of the articles I've read,an engine with a long rod will give you a broader rpm range to make more torque. period! As long as you are running at Daytona!! Most short track engines,such as sprint cars, run a shorter rod ratio for faster acceleration out of the turns. A shorter rod will make more torque at low-mid engine rpms. In case you would like to reference any of this, a magazine called Chrysler Engines Etc. wrote a very nice article on the research that Chrysler did back in the 1950's. Maybe Smokey didn't pass along all of his secrets.

Acceleration is not a major concern on an antique pulling tractor, but torque is.

: : : : : : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : : : : : 1462 Ash,St.
: : : : : : : : : : : Terre Haute,IN 47804
: : : : : : : : : : : 1-812-234-1715
: : : : : : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : : : : : : : : : John,
: : : : : : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : : : : : Chuck,
: : : : : : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : : : : : They are reasonably priced. good luck.

: : : : : : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : : : While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : : : : : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: : : : I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

: : : Chuck,
: : : I think we are looking a basically the same facts. Where we differ is you want to take a long rod motor, "A moline" and make it a short rod engine. A G-226 allis is a fine engine for what it is. I think you will agree it is short lived when compared to a MM though. It's torque at 1100 rpm would be little to a 403 too. : : : Even with well motor heads, best offered.the breathing of a MM is restrictive. 125 ci is hard to feed with a 1.5" valve. The long rod is necessary to let the piston dwell at BDC, botom dead center. If you have read Smokey Yunick on long rods you would know what I mean. The gain with long rods is the most with restrictive heads. : : : Put he longest rod in the SOB and win races, or tractor pulls!!

: : Ihave been following this discussion for quite sometime with some interest,wondering if I should join in. I have been involved with engines for the last couple of decades even though I'm not a professional builder,I have done quite a bit of reading on the subject. According to some of the articles I've read,an engine with a long rod will give you a broader rpm range to make more torque. period! As long as you are running at Daytona!! Most short track engines,such as sprint cars, run a shorter rod ratio for faster acceleration out of the turns. A shorter rod will make more torque at low-mid engine rpms. In case you would like to reference any of this, a magazine called Chrysler Engines Etc. wrote a very nice article on the research that Chrysler did back in the 1950's. Maybe Smokey didn't pass along all of his secrets.

: Acceleration is not a major concern on an antique pulling tractor, but torque is.

Absolutely! A couple of other characteristics of an engine with a short rod ratio are improved breathing because of the downward piston speed and they are more forgiving for being over-cammed. I don't want to seem too brash but,I think that Chuck is on the right track. According to theory, it just sounds right! I think it would be interesting to build two Moline engines just to try at a pull. It would also be nice to have access to the company's engineering notes to see what they experimented with.

: : : : : : : : : Well I have been following along with great interest. I have given this matter a great deal of thought. I have a question. If a long rod is better, would using a "G" rod, short piston, and a "U" crank a good combination for "stock" classes? This gives a ratio of almost 2.25:1. As "G" cranks become harder and harder (i.e. more expensive) to find I wonder if this combination would work well for a guy like me on a tight budget.

: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :Hoosier Regrinding
: : : : : : : : : : : : 1462 Ash,St.
: : : : : : : : : : : : Terre Haute,IN 47804
: : : : : : : : : : : : 1-812-234-1715
: : : : : : : : : : : : I have one of their 800 grind cams and it works great. : : : : : : : : : : : : : : : : : : : : : : : : : : : : : John,
: : : : : : : : : : : I've only heard about the 800 cam. Haven't got mine installed yet. Where is the decisive gain over the stock 283, 403 cam. My worked over LP U at a dimely lite night pull has a 2" flame coming out the exhaust at the tail end of the pull. I suspect more overlap than before guesstimated. Later.
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : This message is a little outside the regular stuff posted, but with the interest in pulling, it might be helpful. Many people wonder about what rod length to use in a motor. Engines will work with rod lengths from about 1.3 times stroke length, to about 2 times stroke length. Short rods (1.3-1.6) will produce the most torque. This is because the short rod works at a steeper angle in relationship to the crank. It is actually pushing the crank more sideways on the power stroke. However, this side push puts a greater load on the rod. As engine speed increases, the side loading increases at a multiping rate, and will break the rod at high RPM. The short rod is also stressed by the greater angularity changes as RPM increases. Long rods (1.7-2) operate at much lower angles in relationship to the crank. They are not swinging side to side as violently as a short rod. Since they are running straighter, they also have lower side loading. The main reason racers use long rods is to keep the bottom end together when running at constant high RPM. Short rods produce torque, but long rods are necessary at high speeds. Our tractor motors running at 1600-2000 RPM should produce the best torque with a short to medium rod. Long rods cause the piston to dwell longer at top and bottom dead center. This extra dwell time at TDC is necessary to allow the combustion process to occur before the piston starts downward and begins releasing compression. Tractor motors at 2000 RPM will automatically hold compression 4 times as long as V8s at 8000, thus allowing complete combustion given good spark. Tractors had long rods from the factory to be ultra reliable. Short rod motors wll wear out quicker (faster cylinder wear from side loading with greater rod angles, more pressure on rod bearings because of sideways stress loading), but this is not really a factor with pulling motors. Detroit used these rules when designing motors. The 454 chevy, a low RPM torque motor had a rod ratio of 1.53 to 1. The 350 was sort of midrange, and was 1.64 to 1. Using a 6" rod in a 350 made it 1.72 to 1, better for high RPM. The 302 had a ratio of 1.9 to 1, making it a revver. Other auto companies' engines were similar in design. The correct rod length to use is mainly dependent on the engines' RPM, slow-short, fast-long. I believe a pulling ratio of 1.45-1.5 to be best, but do not greatly overev. One more thing, wrist pins can be offset to improve rod angles when the rod length can't be changed.

: : : : : : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : : : : : I'm really glad you got into this. The Minneapolis message board is now alot more technologically advanced than the rest.
: : : : : : : : : : : : : : : : : I think you are argueing apples and oranges though. The small block chevy has very little if anything in common with one of these tractor engines. : : : : : : : : : : : : : : : : : For instance the U has a 10" connecting rod and a 5" stroke. A 2:1 rod ratio. The G has a 11.243" rod and a 6" stroke. 1.874:1 rod ratio. These are very torquey engines. To say these engines would develope more torque with a shorter rod is like saying those Minneapolis engineers didn't know what they were doing. : : : : : : : : : : : : : : : : : You also have to take into account wear. These Minneapolis engines were known for being long lasting. The side thrust of the short rod ratio would have shortened the life of the engine.
: : : : : : : : : : : : : : : : : I standing pat with Smokey Yunick, "put the longest rod in the engine and go win races."
: : : : : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : : : : MM You are correct, high RPM auto engines have little in common with tractor engines. This is why what works well for Smokey at 8000 RPM is not the best setup for us at 1500. No engine designer will argue with you that long rods are necessary for high speed, and the longest rods possible are the best. However, engines designed for low end torque all are short rodded. (454, 400 chevy, BB Fords, Mopars were longer, more for racing) Our Moline engines are long rodded for longevity and reliability. I have torn down several U & G motors that showed almost no wear even though they were 50 yrs old and had ran thousands of hrs. Moline engines are torquey because of displacement, not the rod length. Factory stock, they are 20-100 ci. bigger than comparable HP in other brands. MM's also breathe better than most and have a bathtub combustion chamber which research has shown to be the most efficent except for a hemi. Another example - a U rod on a 6.2 " offset ground G crank. Most everyone agrees this is a great setup that makes extra power and torque. The rod ratio of this setup is 1.61-1, right in line with other high torque - low RPM engines.

: : : : : : : : : : : : : : : Chuck, We may have to agree to disagree on this one. It appears we agree that rod ratio is an important factor of engine performance. I still believe the longer rod is better in any application and that is were our difference lies. : : : : : : : : : : : : : : : I have heard shorter stroke WD engines consitently out perform longer stroke ones. The deck height is fixed the piston are limited on compression height. The only way to get a longer stroke in the engine is a shorter connecting rod. This changes the rod ratio on both ends of the equation. The rod angle when the power or torque hits goes from near ideal to less than ideal. : : : : : : : : : : : : : : : Later.

: : : : : : : : : : : : : : I enjoy these discussions. I would like to have time and money enough to build two motors all the same except for the rod length and test them. Then we would know for sure. Meanwhile, you might be able to help me with another question. I would like to know how much torque increases as stroke is increased. Is it equal proportions? Example: Go from 5" to 6" stroke, a 20% increase, will torque increase 20% also? Or is it a multiplier? 5 squared = 25, 6 squared = 36, 44% increase in torque? I know there are many other variables to how an engine works, but if these were held consistent, how would the torque increase? Also, could you list the phone # or address for Hoosier Cams, I have not been able to find them.

: : : : : : : : : : : : : Chuck,
: : : : : : : : : : : : : Two engines have been built. Remember the small block chevy you talked about. Check the Nebraska test on the UB and the GB moline. If you get the right test they have the torque output at the PTO. The GB if I recall had 400 ft lb. at the PTO from 400 engine rpm to 1300. : : : : : : : : : : : : : I'm not going to stick my neck out on how much torque increases when the stroke is increased. It would appear it could be the torque is increased to the square of the stroke. Careful on this one the piston has to come back down after the exhaust stroke. It, the piston, runs against a pillow on compression. On exhaust it weighs four times as much.
: : : : : : : : : : : : : Hoosier cams is in Terra Haute, IN. I don't have there phone # handy. I'll try to get back with that later if you can't find it in the phone book.
: : : : : : : : : : : : : They are reasonably priced. good luck.

: : : : : : : : : : In this discussion of rod length, AC WD's were mentioned. I happened to visit a friend who has one torn down. The rods were about 7.5" long. With a 4.5 stroke, this gives a ratio of 1.66. I can see that if stroke was lengthened, and the rods shortened, the rod ratio would get very low, maybe below 1.4. Too low. However, these engines produce almost the same HP as a "U" but with 50+ ci less. This reinforces my belief that a short rod makes more torque at tractor engine speeds. These AC engines had ideal rod length and ratio. If our "U"'s and Farmall "M"'s had shorter rods they would make more HP, but would probably wear out a little quicker as AC's did.

: : : : : : While you are correct that the WD and the U have the same power with 50" less you have not mentioned the RPM that each run at. The WD is screaming while the U is at 1300 RPM. The WD power comes primarily from that. By comparison the WD is a cheap subsitute. It has four speeds while the U has five. The U will last a life time while a WD may last ten years of severe service. The U can be stripped to 4500 lbs. while the WD can go down to 3000. This shows which has more iron. : : : : : : The WD doesn't necessary get a shorter rod when it is stroked. The common build is BB chevy pistons stroke to five inches and us the same rods. 283 ci.

: : : : : I have a couple more thoughts to state, True, there is no replacement for displacement, but unless the induction system is enlarged in proportion to engine size increases, HP gain becomes a declining relationship to engine size. A 740" though impressive, will not be 50% more powerful than a 500". On 500's, this is a 403 with an overbore and a 7" crank. They are a good combination and will produce 100+ HP with restrictive heads. The long stroke gets max expansion out of a small fuel charge. The long rod holds compression at TDC and makes the engine operate as if it had a higher compression ratio. I would guess this combination maximizes the power output of the old 403. However if the engine can really breathe, ( 800 heads, cam, big induction) a big bore will make more HP. A shorter rod ratio will also help by creating more rotational thrust. Don't be so hard on AC's even though this is the MM board. That little 226 was very efficient, devoloping a HP from each 4 ci bone stock. Yes, the RPM was 350 higher and that helped HP, but they are not a screamer. Maybe a 302 Moline is a screamer. The AC engine was more of an automotive design vs Moline which was industral.

: : : : Chuck,
: : : : I think we are looking a basically the same facts. Where we differ is you want to take a long rod motor, "A moline" and make it a short rod engine. A G-226 allis is a fine engine for what it is. I think you will agree it is short lived when compared to a MM though. It's torque at 1100 rpm would be little to a 403 too. : : : : Even with well motor heads, best offered.the breathing of a MM is restrictive. 125 ci is hard to feed with a 1.5" valve. The long rod is necessary to let the piston dwell at BDC, botom dead center. If you have read Smokey Yunick on long rods you would know what I mean. The gain with long rods is the most with restrictive heads. : : : : Put he longest rod in the SOB and win races, or tractor pulls!!

: : : Ihave been following this discussion for quite sometime with some interest,wondering if I should join in. I have been involved with engines for the last couple of decades even though I'm not a professional builder,I have done quite a bit of reading on the subject. According to some of the articles I've read,an engine with a long rod will give you a broader rpm range to make more torque. period! As long as you are running at Daytona!! Most short track engines,such as sprint cars, run a shorter rod ratio for faster acceleration out of the turns. A shorter rod will make more torque at low-mid engine rpms. In case you would like to reference any of this, a magazine called Chrysler Engines Etc. wrote a very nice article on the research that Chrysler did back in the 1950's. Maybe Smokey didn't pass along all of his secrets.

: : Acceleration is not a major concern on an antique pulling tractor, but torque is.

: Absolutely! A couple of other characteristics of an engine with a short rod ratio are improved breathing because of the downward piston speed and they are more forgiving for being over-cammed. I don't want to seem too brash but,I think that Chuck is on the right track. According to theory, it just sounds right! I think it would be interesting to build two Moline engines just to try at a pull. It would also be nice to have access to the company's engineering notes to see what they experimented with.

Hi, Several replies ago somebody wondered what the Compression Height was of a 3406 Cat piston. The answer is 3.462". The orginal 800 Well motor piston compression height was 3.537". Later

The 800 blocks are Illegal on the four cylinder engines in NATPA's rules even for the new division V, the 800's blocks and the 800 engine are legal only in division V on the six cylinder engines and the tractor can't pull below the 7500lb class. I think they are going to be very stiff about that it's writen in the division V rules in three or four diffrent places.

• Twin City and Minneapolis-Moline tractor and pulling!