Had a similar issue awhile back with my compression tester, ALWAYS showed no more than 90 psi. I bought a new Snap On gauge, and BAM 175/ 180 psi on same engine It’s a bummer you tore your engine down tho Good tho it was nothing but a crappy tool
Verifying your diagnostic tools is something that must be done now 'n' then...and almost no-one does. Faulty gauges, faulty meters, faulty timing lights, faulty thermometers...all can cause major loss of time, patience, hair, and temper. Pressure gauges can be checked against each other using "shop air" and a regulator to bring the compressed air pressure within the range of the gauge(s) to be tested. Does the gauge on the regulator and the gauge on your oil-pressure tester both show "60" when the regulator is turned down to match the oil pressure gauge range? Voltmeters, ohmmeters, etc., can similarly be tested against other meters of the same type.
Bruce, Snap On makes a great gauge but they are spendy. We have 3 or 4 kicking around the shop. The key are the valves. They are not tire Schrader valves, rather special Snap On valves with a different spring tension. And even those fail from time to time.
I've got an old Allen comp gauge and all it has is a metal cap over relief. I think I'll trust it more...nothing to fail.
Putting it back together...have exhaust manifolds with copper gaskets...seems they were leaking in a few spots. Put red high heat Permatex on the gaskets or go with no gaskets and the Permatex? They have not been surfaced so i don't trust them bare. Or go with Remflex?
Many years ago, I was at the GM training center for a diagnostic course. We were divided into groups to do various tests on engines. The instructor asked us why the two groups got two different compression readings on the same engine with the same gauge. He had switched the Schrader valve with a tire valve.
All back together and running great. Tomlinson ported B4B and Gessler ported manifolds. ATTACH=full]562312[/ATTACH]
