signs of low compression and proper compression values ?

[rick 48 cub]

Thanks for all of the info. I will try to give it a compression test tomorrow.

[Bill V in Md]

Dave in Md,

That's a pretty big spread between lowest and highest compression readings. I wonder if there might be a problem with the oil control ring in the cylinder with the highest reading? Before you tear into the engine, I would first check the valve sash for proper clearance. If adjustment is necessary, I would recheck compression after making the adjustment. Good luck.

[George Willer]

I finally got to a compression check on my 53. I recorded 90, 90, 115, and 95. From the reading I've done here and other places 90-95 lbs is acceptable, nothing to worry about. I suspect the 115 lb reading I got on #3 is because of help that cylinder is getting. The plug is always a bit moist so everything else in that cylinder has a little extra sealing capacity due to the extra oil. Before I go tearing into the engine in the next few weeks, can you guys give me an idea what might be causing this? I'm thinking along the lines of a valve issue as opposed to rings since the compression is high compared to the other cylinders. Am I on the right track?
TIA
Dave

Dave,

I don't know if this applies to your tractor, but if there are significant deposits in this one cylinder that will cause the reading to be high... because of the reduced effective volume. Assuming this is true, pulling the head and cleaning the combustion chambers should put it in decent condition for quite a while.

At least it would be a good place to start.

[nosih]

the IH serviceman's Handbook lists that the compression in PSI for the C60 engine at cranking speed should be 125psi. A tired, but servicable engine will probably average at 85 psi at cranking speed.

[Eugene]

I'm not sure that I would tear down the engine just yet.

Bring the engine up to operating temperature. Pull all the spark plugs. Again take the compression readings. The readings should be close to your original readings. Then put a tablespoon of oil in each cylinder - crank the engine over a couple of times. Again take the compression readings. If the readings jump up on the 3 low cylinders, the rings are in question. If the readings stay the same - valves are suspect or as another individual suggested - the #3 cylinder may be carboned up.

I don't know how much or how often you operate this tractor. If this tractor doesn't get ran very often - I would work the tractor for several hours. Then see what happens.

If this tractor were mine and had no other problems I would use it as is.

My opinion only

Eugene.

[Dave in Md]

I hadn't thought about excess carbon build up. The valves were adjusted before I did the compression test. I'll do the wet test next & see if theres a change in the numbers. I've only had the tractor a few months. From what I was told by PO it wasn't used much in the past 2 yrs.
Thanks for the replies and the advice.
Dave

[John *.?-!.* cub owner]

If it hasn't been used much in the last couple years you may have some rings sticking. After you run your tests get some Sea Foam from your local auto parts store and put in the gas, and run a little through the carb. Then work it some.