Originally Posted by bostonzv
hi, so I have a 2003 legacy L and had done the headgaskets three times in the last year and finally decided something else needed to happen. I took it to a mechanic and he rebuilt my engine(2.5L) with a 2.2L block, he said that the heads were warped and he machined them down 5/1000. I have just got the car back and it seems to have a knocking noise coming from the top of the engine, also after a quick test drive a noticeable lag/loss of power. Any Ideas? was this bad or good?
putting in a 2.2 block, with 2.5 heads will drop your compression from 10.5:1 to 8.2:1 (ish) so youre loosing good power and probably running rich as sin now. as for the knocking. my assumption is pistons hitting the head. but piston slap has been known to happen against the rods. all in all. couldnt tell you.