I have a 96 Z LD9 5spd. I have now spun my brand new rods bearings after only about 30 miles of driving. I think my oil pump is bad. I have noticed that after the car warms up and the car idles, the oil pressure is only about 8-9 psi. During acceleration, the pressure looks fine tho, but at high RPMs I think I have seen it make drastic drops out of the corner of my eye.
Thanks guys
"sometimes the respect is more important..."
Did you really only change rod bearings?
Not ruling out a bad pump, but how were you sure the other bearings weren't warn also? or that debris wasn't still in the engine oil galleries? or if the rods weren't out of round?
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did you just slap in new bearings? if that is the case, it is not un heard of that the rods/crank may have slightly ovalized. did you get the crank/rods checked?
I got a brand new crank, main and rod bearings put in. my old crank was un-fixable so i spent the money to get a new crank.
"sometimes the respect is more important..."
also i have reconditioned rods from gm and brand new oe pistons with only 1000 miles on them. the oil pump is the only thing not new in my motor
"sometimes the respect is more important..."
So did you do a complete rebuild, but not replace the oil pump? Also you said this is after about 30 miles on the rebuild and you were already going WOT? If this is true I see many things wrong with this.
FU Tuning
Did you coat the bearings with a heavy oil like STP or some sort product for engine assembly? Could have been the problem if you never had protection while the engine oil was starting to circulate to the crank.
If you pulled the engine and totally cleaned the block passages along with all the new parts you listed, then yes, it really should boil down to just a weak pump that should have been replaced.
But I have seen cars with NO PUMP... as in the idiot did not install or connect the pump drive... that lasted longer than your 30 miles before it became apparent the bearings were bad. So I am suspicious that there may be some other, more exotic, issue causing it too.
Something like:
-an internal crack along the galleries thats leaking oil
-internal gallery plug thats missing
-a bad filter system
-really wrong bearing clearances (too tight or undercut with stock bearings)
since I do not know what you did building this on a personal basis, these are only random guesses that may not apply or may have been checked.
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