LS1Transam99

iTrader: (6)

I recently replaced the rod bearings and the oil pump on my 125k mile '95 z28 and occasionally as I'm slowing to a stop light, the oil pressure drops to 0psi, then when I tap the throttle, it jumps back up. It idles at 20-25psi when warm and 40psi when cold. While cruising its at 60psi cold and 40-45psi while warm. I've only noticed this momentary drop as I'm slowing to a stop light.

Also there is a slight hum coming from the bottom of the oil pan.

Could my new bearings be shot already? I didn't have the crank machined because the journals looked fine. I checked the oil and the level is fine and I'm running SAE 30 oil. The pickup tube went on pretty tight, after it was installed, it wouldnt budge. It's also angled down almost exactly like the old pump/pickup.

Any idea what would cause this?

01WS6/tamu

iTrader: (37)

It sounds like the pump is losing suction during braking cornering. As long as you do not hear a knock the bearings are usually fine did you go with std's or 1 overs. Unless the crank is grooved there is no reason to machine a perfect stock crank. I tightened mine up with 1's on the mains and rods and the oil pressure stays about 40 even at idle and 50-60 on the highway. It could be a goofy sending unit too. I'd start there first.

DeltaT

iTrader: (5)

How far did you position your pickup from the bottom of the pan? It's supposed to be 3/8" to 1/2"max. Sounds like yours might be touching or a lot closer than it should be.

The hum is probably being transmitted into the pan from the metal pickup which is touching.

That needs to be fixed ASAP.

Jim

InnocentZ28

iTrader: (3)

My Dad had that same problem we pulled the pan off and the pickup tube was lying in the pan. We had it welded on this time.