JC66
Mar 24th, 04, 3:19 PM
Threw in the towel 2 days ago and went to a shop with all the diagnostic goodies after trying unsuccessfully to tune the new motor :(
Shop says Cylinders 5 and 8 are running 75 degrees cooler than the rest, measured at the header and both cylinder's plugs are white, showing lean (the rest are brown). Both cylinders share an intake runner (rpm airgap) but no vacuum leaks found.
HT 383 crate with iron vortec heads running 9.6 to 1, gm lt4 hot cam with Crower 1.6/1 ss roller rockers, Holley 850 dp.
Compression good, leakdown good, all electric checks out.
The only thing I can think of that would cause this is a bad runner in the intake (possibly cracked) somewhere in the gap where it is not visible or accessable. Anyone had this problem before?
The shop is stumped so I am going to pick it up now to tear the intake off and start over with new stuff :(
Thx in advance for any input, JC
Shop says Cylinders 5 and 8 are running 75 degrees cooler than the rest, measured at the header and both cylinder's plugs are white, showing lean (the rest are brown). Both cylinders share an intake runner (rpm airgap) but no vacuum leaks found.
HT 383 crate with iron vortec heads running 9.6 to 1, gm lt4 hot cam with Crower 1.6/1 ss roller rockers, Holley 850 dp.
Compression good, leakdown good, all electric checks out.
The only thing I can think of that would cause this is a bad runner in the intake (possibly cracked) somewhere in the gap where it is not visible or accessable. Anyone had this problem before?
The shop is stumped so I am going to pick it up now to tear the intake off and start over with new stuff :(
Thx in advance for any input, JC