brknDSM
Probationary Member
- 11
- 0
- May 9, 2006
-
City,
Delaware
I bought and installed a remanufactured 1g head. Well, appearantly I bought a freaking box of chocolates, because the camshafts appear mismatched. This is some horrible quality control...the intake cam has a very pourous casting like the 1g camshafts have, is stamped "B" while the intake cam has a finer casting finish and no stamp like the 2nd gen cams do. It seems like someone seriously dropped this ball on QC on this auto parts store reman head. (be careful what you buy) I have some 272's to be installed, but this problem must be worked out first.
To the problem: Compression is 180psi across the board, haven't done a leakdown test yet to see if this head holds under pressure. Block was taken to 87mm (built, .1 gram balanced 8500rpm max 4g64 with engine mgmt. Yes, it runs fine up top for extended periods of time and has proven itself) with torque plates top and bottom. The 1g CAS has to be set at 3/4 to full advance for it not to stumble and belch fire out of the muffler after hard acceleration. Valve timing is adanced 3 degrees for the 6mm taller deck. According to the FSM, valve timing is:
IVO 21º BTDC
IVC 51º ATDC
EVO 55º BBDC
EVC 9º ATDC
Is this at .004" valve lift or just rising off/closing on the seat? I highly doubt it's .050" lift? I'm going to double check the valve timing and see if those clowns installed a 1g N/T cams instead of turbo ones. I specifically ordered a late 92 turbo head. The FSM doesn't state at how much valve lift these timing intervals are at. It'd be interesting to see, and I doubt these guys shimmed the valves when they replaced the camshafts. Varying lift might be a problem also. Just tooling around town at night yields 600-700ºC EGT's, maxing at 850º WOT.
You input appreciated
Thanks
To the problem: Compression is 180psi across the board, haven't done a leakdown test yet to see if this head holds under pressure. Block was taken to 87mm (built, .1 gram balanced 8500rpm max 4g64 with engine mgmt. Yes, it runs fine up top for extended periods of time and has proven itself) with torque plates top and bottom. The 1g CAS has to be set at 3/4 to full advance for it not to stumble and belch fire out of the muffler after hard acceleration. Valve timing is adanced 3 degrees for the 6mm taller deck. According to the FSM, valve timing is:
IVO 21º BTDC
IVC 51º ATDC
EVO 55º BBDC
EVC 9º ATDC
Is this at .004" valve lift or just rising off/closing on the seat? I highly doubt it's .050" lift? I'm going to double check the valve timing and see if those clowns installed a 1g N/T cams instead of turbo ones. I specifically ordered a late 92 turbo head. The FSM doesn't state at how much valve lift these timing intervals are at. It'd be interesting to see, and I doubt these guys shimmed the valves when they replaced the camshafts. Varying lift might be a problem also. Just tooling around town at night yields 600-700ºC EGT's, maxing at 850º WOT.
You input appreciated
Thanks
