Sorry for starting another thread, but got new info. I have between 125 and 130 psi on all cylinders except #1. This is weird.....some revolutions there is no compression at all, sometimes 30 and sometimes 90. What is going on? Broken ring? stuck valve? What's this going to involve? This is scary.

BANJOPICKER! Thanks for the advice. I found timing chain slack to be around 8 degrees. From what you said, that's OK? Thanks much.

 

It sounds like a bad valve, one easy way to test is get an air chuck with a rubber end, bring the cyl to tdc on the compression stroke,. and blow air into the spark plug hole, have some one else listen by the exhaust outlet for air escaping, this will tell you if a valve is leaking.

Bill

 

Well, I retest this morning and have 130 psi on #1 cylinder????? I guess I'm just an idiot. I tested 3 times last night and got varying low results. Thnaks

 

What you are describing sounds like intermittent valve train problems, perhaps lifters.

The "standard" way to determine if low compression is due to rings is to squirt a little bit of oil in the spark plug hole and check again, if the compression increases, then the rings need attention, if compression is still low, the valves are the likely problem. If the intake valve is leaking, I don't think you would hear it at the exhaust.

 

Is your compression Gage fitting the type with an O-Ring to seal it to the head?
I've seen the O-Ring squeezed out thus leak in the past.
Lifter is very likely, or a sticky valve if it's sat a while or been over heated before.

44Dwarf

 

Problem solved. My mechanic found the dwell to be way off. As far as the compression fiasco, I plead guilty. I must have inadvertently had my finger on the pressure relief button or something. Thanks so much for your input.

 

Points not gapped correctly...

--Mike