924Board.org

[KenneBraun]

Hi all,

I was recently gifted an ‘88 924S that hasn’t been driven in a good 8 years. After replacing most of the ignition system (plugs, wires, distributor cap, battery), I got it running, but it spews lots of oil smoke from the exhaust and runs terribly. Compression test results seem pretty good best I can tell (167, 175, 170, 160) and leak down test was all at 9% or better even when tested completely cold. Heard some blow by through the intake in cylinder 3.

With this, I’m suspecting my valve seals as the source of the oil in the combustion chamber. Does that stand to reason? If that is indeed the culprit, do you all recommend a valve seal replacement with the head still in the engine bay? Or should I do a full head rebuild just to be safe? Any suggestions how to further determine whether a valve seal replacement is likely to solve my smoke issue?

Thanks!

[barnwerks]

Replacing valve seals is not likely to remedy the oil burning. Generally the seals only fail after the guides are worn out of spec so even if new seals slow the oil, it won't be for long. From my experience, it is more likely that the ring package is stuck. A combination of dirty oil when the car was in service and moisture ingress when the car was out of service can lead to the oil and scraper rings becoming stuck in the pistons. Running the engine in this condition will only damage the fragile alusil bores. I recommend, as a first step, removing the cylinder head to examine the condition of the bores.

[KenneBraun]

Thank you for the advice. I was leaning that direction, but didn’t want to do more than necessary. Given your recommendation and the points you make, I’ll definitely go ahead and remove the head entirely.