Starion Engine compression

[Will]

I'm getting around 120psi. Is this low or normal? If its low, then what numbers should I expect from a healthy, but well used engine.

[decoy]

i think thats about right, are they all the same?

[NXTIME]

I think that is right (with the ower comp of the starion engine), but so long as they are with 5 psi of each other the engine will be fine.

[Will]

Thanks for the quick replies! I measured 120psi only on #1 and #4. I'm using one of those dodgy 'push-on' compression testers and couldn't get it to go onto cyl. 3 and 4. The spark plug on #1 was a lot more oily than the others however, but it measures OK. :?

This is the comp from my engine that wants heaps of ign. advance, so I was hoping these readings were low. Doh! :roll: I've checked over crank and cam timing more times than I can remember now, so I'm going to swap engines because I have a spare which originally was in the car (was swapped out by the previous owner), and the current engine has never run right. I've been told the old engine is actually still good, but I'll soon find out.

[pcuser51]

:D Hi will my compresion is lower than yours at around 90psi but still
makes 131rwh with 3inch exc & 12psi of boost 8)

[Cam]

You have to remember it depends on how you do a compression test as to what reading you will get. If you have your foot on the gas you will get a different reading to if you dont. alot higher one . Well thats what happens with my car anyways

[Will]

I believe that its part of the procedure to always measure at wide open throttle, and to crank until the reading peaks. This is the method I use anyway.