Topic: Engine Compression question

[lhemrick]

I have a used 72 350f engine that I know nothing about but all the cylinders but one have great compression. It only has about 80 lbs; is there anything I can do or check short of ripping it apart to replace the rings?

Lynn Hemrick

[333]

Try adjusting the valves and check again. 

[scunny]

what 333 said
after that, if there is no improvement put a teaspoon of oil down the spark plug hole, repeat compression test. if no change it is valves, if the compression improves it's rings

[MRieck]

 A leakdown test will show you where you are losing pressure.

[TwoTired]

In addition to what has been said, periods of inactivity can deteriorate the ring seal.  If it isn't too bad, they will re-seat in about 100 miles.  If the compression is still wonky after that, it's time to open it up.

Cheers,

[lhemrick]

Thanks for the fast response guys! I have already put a couple of tablespoons of oil in that cylinder and the compression came right up to normal. I was wondering if it would or might get better if I just got it running and got it hot a time or two and I think I might try that first. Actually I have two engines and the other has a couple of weak cylinders also but the man I bought them from promised me that they both run and they are nice clean engines and are well worth what I paid for them. I would just really rather not open them up if I don't have to. Any other ideas?

Lynn Hemrick

[ofreen]

As Lloyd said, just run it and see what happens.  Odds are good it will heal itself.