re: Here's another weird one......

This is a follow-up to my post on 10/7. I was wondering why my '50 8N would run a stream of oil out the breather cap when it warmed up. It seems to get worse when the tractor goes UPHILL (I mistakenly said downhill in the post). I got replies from Dell and Fast Ed (who both thought it might be an overfilled crankcase) and Evil Steve (who thought it was a broken ring).

Well, I bought a compression tester and ran the wet/dry tests on both my 8N and my 2N (with an early 8N motor) and here's what came up:

8N

Cylinder Dry Wet

1 80 95
2 95 95
3 95 100
4 105 105

2N

Cylinder Dry Wet

1 80 95
2 95 105
3 97 100
4 85 90

In my infinite ignorance, I've come to the following conclusions:

1.) While the compression readings are somewhat low, I don't feel they indicate a broken ring(s).

2.) I'm baffled as to why the 8N blows oil out the breather when it has better compression readings than the 2N, which blows no oil at all.

3.) Also, even though the 2N's readings are lower, it seems to have more power, and runs smoother than the 8N.

4.) I also changed the oil and filter on each tractor. I only put in 5 quarts in each. The 8N (which I bush hogged with on Sunday for 2 hours) still insists on blowing out oil.

5.) Could the valves be at fault here?

Help! I'm once again open to all comments/suggestions!

TIA

Ron

To my knowledge, there's no other way to vent the crankcase other than the breather/oil fill tube. No PCV valve or one such as you have described on your Fergie.

Ron

Thanks for the comments. I guess what I REALLY want to know is, is it safe for me to run the tractor this way, or should I tear it down and change rings? I don't want to do anything to ruin the engine, but I really need the tractor now. I'll 'sift through' the oil I changed tonight after I get home to see if there're any DECTECTABLE metal filings in it.

Thanks again!

Ron

If you remember, I also suggested that your crankcase may be overfilled. You also asked for an explanation as to why your tractor smoked/had higher blow-by while under load. I gave you a fairly detailed answer as to what blow-by is and what are its causes. I also suggested that someone may have installed an oil slinger on #2 rod during some past overhaul. I think I offered possible causes for each question.

As to your test results:

The big jump in pressure on #1 on your 8N and #1 and #2 on your 2N indicates a ring problem. Could be just worn or could be broken. Each low reading is also below minimum specs. Any or all of these can cause blow-by which was a main question you had if I remember correctly.

Your valves will NOT cause oil to blow out the breather cap and your tests do not indicate you have any material valve problem. Ain't your valves! Valves have nothing to do with blow-by on these flatheads.

You came to the conclusion that it isn't a broken ring. How? It PROBABLY isn't but your test results also don't rule that out. You have two compression rings on each piston. Just one can provide the pressure you are getting on those low cylinders.

Have you pulled the breather cap off and shined a flashlight down the tube to see what's going on?

Sorry if I sounded like I didn't go for your explanation--I just didn't realize that a cylinder could still develop 80# psi with a broken ring. I'll look down the filler tube. I know it does have a baffle, because I can see it without a flashlight. Thanks for your input!

Ron

Whren the breather cap first started to leak, I bought a new one (about two months ago) from NH. It leaks like the original.

Ron