how hard to run a diesel engine?????

But I think that Detroit Diesel is an odd duck, and the rules of operation for that 2 cycle shouldn't necessarily carry over to elderly 4 cycles just because they burn oil for fuel.

1) Never lug the engine

2.)Don't overload it

Some people swear by running engines around 1500 no higher, but I used to do that and I went thru engine like water. I have a 3594 CIH now that has over 9000 hrs on it right now- no over haul and been run like I say, runs like a top. It's probably a bit of personal prefernce to it too, my Dad alway ran them at such and such so I do...

See ya,

John I

How to tell if it’s lugging? So long as the engine RPMs hold up and it pulls thru hard spots, you see no black exhaust smoke when it’s pulling hard and the temperature stays normal, it’s not being lugged.

Why do this? By reducing RPM’s it reduces wear on the engine and saves significantly on fuel.

My experience is this strategy works. Have found a JD 8960 (370 HP Cummins governed at 2,100 PRM) will run happily all day long loafing along at 1,200-1,300 RPM pulling a light load. Same with an 8300 (rated 210(?) HP at 2,300 RPM) worked light.

What’s also signicant is the reduced NOISE! Even inside the factory cab the reduction in fan roar, etc. when throttled down is very noticable.

The torque curve of a typical diesel engine peaks ahead of, but fairly close to its full rated RPM, also called the high-idle speed or maximum governed speed. Because of this fact, it is common to hear folks say that the diesel is most efficient running at full speed. However, like any other engine, the fuel delivery and engine speed should be adjusted as needed to meet engine loads. There is no reason to run a diesel at full speed, (say to pull a cultivator) and then have to shift the transmission into low range to maintain the desired ground speed. If the engine can handle the load at lower speeds, then run it at lower speeds. As the other post said--you should never lug a diesel--that is, overload it at low RPM's to a point where black smoking and fuel knocking occurs. This condition places tremendous loads on engine bearings (rods, mains and wrist pins) and also causes excessive combustion pressures. Increasing the throttle at low RPM and high loads simply dumps more fuel into the engine and increased pressures result along with possible engine damage.

Full throttle is a bit of a myth. Look at the big rigs on highway, most of them never run at full throttle. Most of them at 65 mph are turning 1,650 rpm in high gear. Cat will even tell you not to be afraid to lug their truck engines to 1,000 rpm, short term, if it avoids spinning out on an icy hill, from shifting gears.

Remember the efficiency of a diesel lies in that maximum torque at low rpm. You see guys buy a diesel pickup, put in 4.10 axle gears so it will make lots of noise and burn just as much fuel as a gasser. Plus it will turn 2,800 rpm on highway driving. I ran a 6,2 Chevy with 3.24 gears half million miles with no rebulild and got 30 miles to Canadian gallon (24 US) It turned 1,800 rpm on highway. And we all considered the 6.2 a Mickey Mouse affair.

After my many years experience with diesels I would never buy another diesel with a governed range higher than 2,000 rpm. Just look at the 475 hp Cat on highway, governed under 2,000 rpm, pulling 140,000 lbs, it will accelerate just as fast in either of the two closest gears, at about 40 mph. IH and Deere for example didn't need 2,400 rpm to get same hp out of those diesels they were using in the 70s. RPM's were just to wear then out faster. There was no choice standard pto was at 2,300 rpm, or there abouts.

I always heard "run a diesel hard and high but don't abuse it". Keep the RPM's up there, it doesn't have to be screaming, but it shouldn't be lugged down past say 2000R RPM on a modern tractor... As for running it hard, select the highest gear that will pull your load without lugging it down past 2000RPM. Just make sure you don't abuse it, keep an eye on the temp guage and the pyrometer.

God bless and have fun!

Pawel

With most diesels, there's no reason you can't throttle back a bit, and shift up, if it will pull the load.

However, you don't want to lug a diesel down below it's peak torque RPM (which is usually considerably lower than max RPM's).

He's right. Those diesels are built to work; anything less and they start pouting. :>)

Allan