Good or bad compression?

Hey guys, I have a question regarding my compression test today. Here's the results.

Piston 1: 140psi
Piston 2: 140psi
Piston 3: 155psi
Piston 4: 155psi

I did the test thinking i blew a headgasket. It was blowing white smoke(antifreeze?) out the tail pipe for about 10 minutes as I was driving, then it quit after I let it sit, and hasn't done it since. But these numbers are too high i would think to be a headgasket. My question is the jump between pistons 1,2 and pistons 3,4. Is this a bad thing? 15 psi? And aren't adjacent pistons usually different, instead of the same in this case. The car just rolled over 150,000 on stock internals. Give me some feedback!

No comment... anyone?

anything below 145 psi is what mitsubishi calls the "service mark" it might be time for a re-build anyways.

Are you kidding? That compression is awesome, it's the difference between the cylinders that i'm concerned about. And service limit is 121.

isn't the best possible compression around 180?
140-155 doesn't sound that bad to me...
Just a side question for tsipsi20.... How did you do your compression test? You will get different results if the engine is warm and if it is cold... just thought i'd ask...

service is 121
standard is 160

This is a snapshot taken from Mitchell1
http://files.automotiveforums.com/gallery/watermark.php?file=/503/231602compression-med.JPG

This shows the minimum compression, did a full search on Mitchell1 and it does not show the recommended compression.

From the looks of it, 6-bolt turbo minimum compression is 114psi, while the 7-bolt turbo minimum compression is 121psi.

im going to take a stab in the dark. im thinking carbon deposits. try some seafoam.

I actually just did the seafoam thing about a month ago. Fed it through the vaccum line from the BOV to the intake manifold. I've changed the oil and filter since, so I doubt it was smoking because of the seafoam.

Oh and I tested it with the engine at nearly operating temperature, with the TB wide open. It was a dry test though, i didn't see the need to pour any oil down the spark plug holes to test the rings because the compression was already high enough in my opinion. The first compression stroke shot to about 70 psi, so i doubt the ring is the problem.

sorry i was skimming. well. might be coolant from a leaky head gasket. could have a bad cat.

good, i was about to post a thread similar to this one....i ran a compression test on my car today. had a buddy help me do it. my compression reads 145 for all 4 cylinders...do i have a problem here or what? i thought i should be somewhere around 175 or so. at least i'm not around 120. any help would be great.

That's damn good compression. Especially since it's consistent in all 4 cylinders, unlike my test. Standard compression is 164 psi, with the service limit being 121. You're on the better end of the spectrum, I'd take that anyday! :cheers:

Standard compression is 164 psi, with the service limit being 121...

Just to clear things up(again), you have a 1990 DSM which has a 6-bolt, meaning the service limit is 114psi. 121psi is the service limit for a 7-bolt, as I have mentioned in the last post.

Yes, my bad, thanks!