Well I purchased this evo broke so I am in the process of getting it tore down and fixed.

Car ran fine, felt down on power. Did not smoke one bit. Sounded like valvetrain noise. Compression test was ~150, ~150, 0, ~145 respectively from 1 through 4. I bought the car assuming something in the head.

Well I was wrong, head looks mint. And here is what I found.

"Scoring" on ALL of the intake side of the cylinders.
Number 3 cylinder scoring was deepest, number 4 was more area but not nearly as rough. Almost looks like it is just deep enough to wipe the crosshatching off. You barley feel anything with your finger but definitely feel some scoring with your nail. Deeper down the bore is worse as you could imagine where the most force on the sidewall is.

What do you think caused it? Everything else looked perfect. Motor came apart very easy, I was expecting way worse.

Was the car run low on oil?
I thought maybe a squirter got plugged but on all four?
Etc, Etc, Etc I could come up with a handful of ideas.
What are your thoughts?


Obviously I have to do some measuring and take it to a machine shop but any ideas if maybe I can get away with a hone or should I just do it right and punch it 20 over?

 

Cyl #3 probably looks that way because of n compression and fuel passing by the rings. Look for bent valves in the head.