Hey everyone, been doing alot of reading on this one but haven't found an answer to this question. Is it possible to have a bad oil control ring but still have good compression?

I ask because my motor is a recent rebuild, got about 1500 miles on it now, and it's using alot of oil, about 1 quart per 400 miles or so. It doesn't smoke on hard acceleration or at idle, it does have the old familiar puff of smoke sometimes on start up, but not always and not very much. The only time I really notice it putting out blue smoke is letting off the gas during shifting and especially when the throttle is closed and engine braking. The plugs don't come out wet, they actually look pretty good. The compression is good, between 170 and 180 on all cylinders. I think the most obvious solution seems to be valve seals, but the heads were rebuilt by a shop I trust. I did the rebuild of the motor, maybe I messed up the rings? I'll take a look at the seals as soon as I get a spring compressor, but I am mainly wondering about an answer to this oil control ring question.

Thanks

 

i have never seen a car with a bad oil control ring that didn't smoke constantly, sure you don't have a leak? it would seem to me if your getting a puff of smoke on start the people who rebuilt your heads may not have greased the valve seals before putting them in, so your head probably ate the seals up before oil got there, just my 2 cents.

 

I agree.
And it is possible to have good compression with a bad oil ring. Your primary and secondary compression rings are the ones to give you your compression.

 

ok, obviously I'm hopeful it's just the seals, but the way my luck has been going with this car lately it probably isn't. I understand the oil control rings don't actually provide the compression, I thought perhaps there was something systematic with having a bad oil control ring that could preclude the compression rings from sealing. It is encouraging to hear that a bad oil ring should smoke all the time because it definately doesn't.

thanks for the replies

 

Not that it matters, but smoke on decel is very commonly a valve stem clearance problem, and not rings. If the valve guides were knurled instead of having bronze inserts installed, that's a Band-Aid fix which might last about 5,000 miles, or in your case, 1,500 miles.

 

took another look at the spark plugs and I noticed that they do seem to have a pattern indicative of something leaking in from the intake valve. Here is a picture of the number 8 plug sitting like it would be in the head:



Is this the typical pattern that I have heard described to indicate a leak from the intake valve?