High oil pressure

[jme821]

I have a 1936 Plymouth P2 that is experiencing higher than normal oil pressure at around 30mph. The shop  manual states that it should be between 30-45psi. I’m experiencing 60psi. I’ve researched replacing the oil pressure relief valve spring with a lower spring rate spring but both manual (Motors and Mopar) suggested only replacing the spring with what is there already. If it was regular, replace with a regular. If it were a higher or lower, then the same. The engine was freshly rebuilt and has 250 miles on it. Has anybody ignored the manuals and changed the spring rate to adjust the oil pressure?  Thank you. 

 

Edited March 18, 2019 by jme821

[martybose]

Have you tried to take apart the oil pressure regulator?  It is far more likely that it is stuck due to old oil shellac forming than it is to actually need a different spring.  You should be able to unscrew it at the left side center of the block.

 

Marty

[dpollo]

The engine likely got the newer "Gyrotor" pump which will increase oil pressure.  60 lbs at 30 mph is higher than what is called for but will do no real harm.

(30 lbs @60 mph is another problem)

The dashboard gauge may not be accurate so before tearing into things, substitute another gauge on a temporary basis.

The next step is to do what Marty suggests, however a pressure relief plunger which is stuck in the closed position could result in pressures up to 100 lbs on a cold engine.

[thebeebe5]

After rebuiling my ‘37s  201cid  I get 60psi at speed running Valvoline 10w/30 VR1 oil.  That drops to between 55-60 on a hot day/long drive.  Idle is a tick under 40psi.   I’d rather have a bit more than too little.   Yours doesn’t sound too out of line.  

[johnsartain]

60 psi doesn't sound like a big issue. The gauge goes up to 80, if I remember right. As long as you don't peg your gauge, there are not any other problems that will likely occur at 60 psi or less.

[casper50]

After my rebuild mine pegged the needle.  Tried lower viscosity oil no good, bought a new pressure valve still high, took a few coils off of the spring a bit at a time and got it down to 60psi at 55 mph if it's a real hot day up here and the temp reaches 180 on the meter it will drop to 57 but I can drive most of the summer up here and rarely will the temp get to the 180 thermostat operating temp.