Jim is having some issues with oil pressure anyone wishing to comment please feel free to do so and copy reply to him and thanks in advance to all who might reply.
Eddie,
I want to get your input. I have a 70 390 that was recently rebuilt. About 80 miles on the engine. I put in a mechanical oil pressure gauge with copper line. At start up (1200 rpm/high choke) I have 40 lbs pressure. When it kicks down to idle (700 rpm) and the oil starts heating up I lose pressure. It goes down as the oil heats. After about 7 minutes I rev it up to 2200 rpm (about cruising speed) and have 25 lbs. of pressure. After about 12 minutes it is down to 10lbs.
Input from the AMC forum is that I need to check the pressure relief valve. Could that be the problem. If that was defective wouldn't the pressure remain a constant?
Do you have any ideas? Input?
I don't hear any scary noises from the engine.
I pulled and cut the oil filter and found no metal shavings.
Thanks,
Jim
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