compression number no good

[ryan15]

So I got 160, 155, 160, 135, No signs of headgasket failure, no oil and coolant mixture, stays at full mark after 3k miles of oil change so burns no oil, 19-22in/hg vacuum at idle.

I am kinda concerned about this, does this mean I for sure need a rebuild or should I roll like this for a while?

Ryan

[DrifterProdigy85]

Id be weary of it. 135 is still alright but being much lower than the other 3, id get some cash ahead for when it gives way. It sounds like the compression rings are worn out some. You'll know when it gets really bad, the compression goes past the rings and into the crankcase causing excessive blowbye.

[ryan15]

Just kinda sucks, that cash is set aside for a ls1 swap, lol, I might pull this motor and throw a KA in there.

Ryan

[IanS]

You may have just gotten a bad result on that cylinder, you could try retesting.

I see no reason not to continue driving the car with the current engine, even if it fails further, it wont really cause any nasty damage, and its unlikely to leave you stranded.

[ryan15]

I will test it after I drive from Northern oregon, to AZ tommorow haha. I dont think it will be an issue, time to start piecing together LS1 parts.

Ryan

[Neil]

Your gauge might be reading a little optimistic since the FSM says standard compression is 156psi. Cyl.4 definitely appears beyond the 14psi variation limit. try doing the small test described here:

[vanquish2]

I was running 12's in the 1/4 with only 85 psi in each cylinder......135 will be good for a while....but I would check your tool and make sure it isn't failing and causing a bad reading.