So I have a friend whos looking at an evo and since I own one hes been asking me what to talk to this guy about.
The car had a new shortblock put in with an evo 9 headgasket. However when I found out the compression numbers its 120 across the board which would normally be a sign of an engine rebuild being needed in the near future. Since its stock specs in the motor I thought it would be 160 +/- 15 across the board.
The guy who owns the car said that the evo 9 headgasket will cause a lower compression but I just wanna make sure my buddy isnt getting screwed.

Cheers

Colton

 

Sounds like the seller is full of ****, red flags, run away.

 

Thats what I figured a head gadket should not change compression numbers

 

Don't forget you're in New Mexico at higher altitude. Your compression readings will be lower, not neccasarily that low. For example I'm on stock block with built head and gsc s3 cams. My compression is 140 across the board. I did a wet test and compression jumped up 5psi each cylinder. So the motor is good. I'm also in New Mexico. What cams does the guy have if any? Also do a wet test to see if there's any variance.

 

There are many feasible reasons for the compression to be that low, but the sellers reason was not one of them, and that is the red flag.

 

Yes you're right, this could be a red flag but theoretically an Evo 9 headgasket is thicker than an 8. So that could cause lower compression correct? That's assuming he put a 9 gasket on a 8 motor. Either way as a buyer I would do a dry/wet compression test and a leak down if need be before I look into anything else first. I wouldn't let this push me way from the car if the wet/leak down test checks out.

 

Could a thicker head gasket cause a compression drop, sure. That much of a compression drop, i don't think so.

 

He is running kelford 272/272 cams

 

Don't worry about the numbers. Do a dry/wet test and a leak down test. If the numbers are within tolerance it's fine. What compression tester are you using? Is it old? Different compression testers will give different results. Like biggie said there's a lot of factors.

 

These are the numbers the current owner gave my friend so I am not sure what tester was used.

 

IMO if everything else seems legit, Have a PPI (pre purchase inspection) done by a reputable shop / mitsu dealer, and take any guess work out of the equation.

 

if the compression tester is on an extended tube and doesn't have a check-valve in it, it will read low

 

Is there a good shop in the denver area