compression

[Jay Jacobellis]

With the head configuration we have to run what is the compression number we are looking for.

[Bill Bonow]

I have no idea of a PSI number, not really a good method. A leak down test will give you a much better understanding of what's going on.

[provamo]

what is your altitude?

[sracing]

what is your altitude?

and compression ratio and starter motor speed and throttle position and temperature, etc...

A compression check is only valuable in telling you that all cylinders are PROBABLY OK if all cylinders read about the same. Actual readings will vary greatly for the above reasons

IE, If they all read 100 PSI or 130 PSI things are probably good If one reads 80 PSI and the others read as above, you know you have a problem in THAT cylinder.

So.... the compression number you are looing for is one that is the same for all cylinders. (+/- 10%)

A Leakdown Gauge test is the proper thing to use to evaluate an engine.

[MrGas]

Jay are you asking what the static compression ratio as defined by the rules? 8.43:1