Ive got a small block 400 in my 81 Z. When the engine temp gets warm the oil pressure drops and when I get on the gas hard it drops to almost zero. Anyone know whats going on (oil pump, bearings?). BTW the oil level is good.

 

Almost sounds like your pump pick up fell off. When beaings start to wear out, the oil pressure will drop at idle but rise when you rev the engine.

 

Deffinetly don't get on it until you find out exactly what it is... don't want to end up spinning a bearing. I dropped the oil pan in my bird, without pulling the engine.. you could probably do that and check out the oil pump. You still need an engine hoist though, to lift the engine enough to get the pan off.

 

Not to state the obvious, but are you low on oil? This'll happen when you're a quart or two low

 

I had this happen to me on my circle track SBC. I assumed that it was an internal leak. After tearing the motor down and setting up a test to check oil flow, checking bearing clearances, etc, I found that the oil filter was somehow restricting oil to the motor when it got warm. Changed the filter, fixed it.

However, I have the oil bypass plugged as a racing mod. In a stock oil system, the bypass should let any oil from a clogged filter to flow to the the motor. If you haven't changed the filter, it's any easy fix before trying anything radical like I did.

Here is the the topic about my problem on another board.

http://www.4m.net/showthread.php?t=129215