Since site activity is slowing down for the holidays, I thought I’d share my recent diagnosis and major repair.
It’s a tale of an uncommon failure that was tricky to isolate and of course a pain to fix.Short background is a Z1 stage2 TT block, rebuilt heads w/ manley valves and JWT springs so nothing wild for the street on pump 93.
It’s been running for two years with about 10k on the clock. Not a dd but at least once a week we get out. Returning from work one evening I noticed the vg was ticking unusually loudly with the frequency based on RPM’s.
Vacuum and oil were fine but the idle as not as smooth. No, boost was not going to help and I was not about to try.
The noise was centered at the front corner by cylinder one and definitely in the head. Hoping for a simple fix I swapped out the CAS to no avail which really started to worry me.
Next, I checked the timing set and compression but those were fine also. Rolled up sleeves, pulled plenum and valve covers for a closer look at the
cams/lifters but nothing obvious was rewarding my efforts.
With everything visible I turned the engine over by hand while observing the valvetrain. Has each cam lobe set pushed down the lifters I watched the oil flow
out of the holes on top of each lifter. Oil was push out of each lifter all except one on the inside intake valve at cylinder one. This brought a since of relief
and anxiety having found the problem and realizing the solution. During the rebuild I had completely gone through all the stock lifters piece by piece.
I can’t recall hearing about z32 lifter failures, so I was somewhat surprised. Additional stressors related to obtaining an nla Nissan lifter began to surface
as I was removing the fresh timing set and intake cam. I was super relieved when Bernie send down a new oe lifter (and CAS), he is a lifesaver. The price of the aftermarket lifters scares me off, way to cheap to be any good.
Also for those wondering, the autopsy on the beat lifter was not conclusive. No visible damage or debris to report (?)
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