Hi there

Ive found a evo 8 that might interest me,

I did a compression test on it,

I had

1- 165
2- 145..
3- 165
4- 165

Should i worry? Or not buy it at all.. Its the only thing ive found on the car..

 

Sounds fine to me, add more boost

 

The car doesnt burn oil at all, but it seems a hudge 20 psi difference ,

 

Any more input on this ?

Also the sunroof does not tilt or open, but i heard the motor working fine,

 

Obviously something in #2 is off.....

I'm not an expert with compression numbers but normally you want them all to be similar.

It's how similar they are more than the peak number in my opinion.

 

First off, was the car warmed up during this test? also, did you test each cylinder twice? I test each cylinder twice, so I can make sure the numbers are accurate.

Next, that #2 cylinder has something up, if the numbers are correct. You may wanna try putting a lil oil into that cylinder and retesting. If the compression goes up after putting oil in the cylinder, then the issue is the rings. If it stays the same, then move on to a leak down test to find your issue.

Last, the spec for difference in cylinders is 14psi.

 

Thanks for the responce,

I tested number 2 three time just to be sure, i have a good gage ( mac tool ) also so the problem is not here,

The car was warmed right, i did the compression test right after the roadtest,

If it would be piston ring, how long the car can still run like that,

If its the valve, how long can it run like that?

Thanks

 

Upp

I guess the guy is just trying to rip off a noob kid, you should have seen his face when i showed him my gage haha..

 

I've had a piece of carbon stick on a valve and give some messed up results on both compression and leakdown, mind you this was on 911 aircooled, but it's still an engine. I'd run the engine again, and retest it.

 

Tomorow it will go to a leak down test, so will have some good or bad new tomorow....

 

No one want to share his experiance?

 

it's probably a valve. I had the exact same compression numbers as you but cylinder two got worse as the months went by(from 145 to 135). did a leakdown test and found that i was losing compression from the intake valve.

 

I'd lean in this direction too...
... and I don't think someone is trying to 'rip you off'... it happens dude, as you even stated, you can't even tell.

 

With a valve job to do on the car, it doesnt worth anymore 20 000 i guess

 

Unless this was a garage queen, this is getting to be an old car. The only thing that surprises me about the compression readings are the three cylinders.