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Low Compression...

turbophein

Well-known member
Joined
Feb 17, 2009
Messages
683
Location
mass
i have 60-60-60-70 psi compression, car starts and runs fine, but has insane turbo lag, like 4500rpm before boost, then the car turns the power on to where you would think nothing is wrong. it will idle all day and it starts right up on the coldest days.

i have a feeling its my Head. i just jumped timing a while back and blew the motor. i swapped blocks and replaced all the exhaust valves in the head with used ones form another member. i lapped them in pretty good but maybe intake valves were bad, although i saw no contact marks on the piston, maybe i overlooked them.

also when i had that head resurfaced, i noticed it was significantly angled, meaning that the intake side was cut in at least 3/8" deeper than the exhaust side, still flat just at a severe angle. not sure how that would affect anything, but looking back at all the problems i had since the new motor, it might make sense. i blew out 2 headgaskets using arp's and copper spray. i've never had good turbo response since. i mean i replaced the turbo, manifold, o2 housing, TB,IC piping, piston and rings. Gaskets everywhere and it still never fixed anything or raised compression.

i think tomorrow i will try a leak down test for the first time. i hope after all this time a head swap will cure the issue... i hope the bottom end is still good, the motor just purs and sounds so smooth since i rebuilt it reusing the same head.

Any input would be great!


thanks
 
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