Thread: 402 High oil pressure

Tweet

Yes big block. No, don't have restrictor plugs. Haven't taken the engine apart yet. Thanks for the help.

You need to find out how much pressure you actually have, so I would suggest an accurate test instrument type gauge (often available at parts store loan a tool) but it's quite possible you have a stuck oil pressure by-pass relief valve in the oil pump. Did you use a oil pre-lube shaft to supply pressure though the engine before firing it up? Also, I agree that engines should be broken in only with regular "dino" oil, but this is not what's causing your problem. Did you check the "high volume" pump clearances prior to installation? Still suspect the pressure relief valve.