Compression

[Bunta]

Me and my buddie did a compression test on my car a few days ago and I was just wondering what these numbers sound like to you guys

120,115,125,145 (I don't quite remember if these were the exact numbers but it was something to that matter)

[1ViciousGSX]

Looks like an engine with some miles on it, usually 4g63/64 engines are a little higher than that, assuming you have a 4g63/64 since you didn't say.

[Bunta]

yeah 4g63.

1990 Eagle Talon TSI AWD.
123,XXX miles on it.

[Shane@DBPerformance]

Something like 164psi is factory compression. You are probably close to the service limit on some of those cylinders.

[niterydr]

Cylinder with 115 worries me, 120 is also a bit low.

The varience between the cylinders is the key thing, max varience between cylinders shouldn't be more than 15psi.

I'd redue the test. Did you do it warm or cold?
Leakdown test?

[Bunta]

well I guess you could say I did it when it was kind of warm. I guess I'll wait till the car has been sitting for a while and the weather out there isn't so nasty.

[xveganxcowboyx]

You want to get it up to full operating temperature. Drive it pretty hard. Make sure the throttle is all the way open when you do the test. Redo it with a cap full of oil in each cylinder when you are done.

[Shane@DBPerformance]

If you put oil in each cylinder, it will give a false higher reading. DSMs have dished pistons with will hold that oil, which will make the combustion chamber smaller and raise the compression. His numbers aren't good, still high enough to run and everything, but a step away from being done.

[Bunta]

Engine rebuild? head gasket? or what should be done in this situation?

[Pushit2.0]

I would do a leak down test to see where your compression is going, valve seats, rings, head gasket. Does the car run funny? why did you do a compression test?

~John