Help with V-8 oil pressure problem

Hi all,

I recently picked up a '75 Bricklin with a Ford 351W V8 and auto trans. The engine runs well and has good compression, but the oil pressure is low. Down to about 10 psi at 600rpm in-gear idle and up to 40psi if I rev it up. Oil (20W-50) and filter are new. The car only has 40k on it, but has sat for long periods of time.

What are the chance of a bad oil pump or clogged pickup sceen versus bad bearings? I will have to lift the engine to pull the oil pan and would like to know if it's worth trying to just swap the pump and clean the screen. Has anyone swapped main bearings in-situ?

Any help is greatly appreciated!

Craig

The oil pump is a likely candidate. In the oil pump, I'd be looking for a stuck or open oil relief valve that failed to close after being opened under a cold start or oil pressure surge. If the pump looks fine on disassembly, that doesn't mean the pump is necessarily okay as the relief valve could have reclosed during the movement of removing it from the engine. While the pump is apart, insure all clearances including the rotor to baseplate are within spec.

If you rule out the pump, pull a couple of mains including the very front one and check for wear. The large main journal diameters of the 351W require much more oil than similarly displaced engines and subsequently, any bearing or crankshaft wear in this area has a much more negative impact on oil pressure than would be normally seen.

Granted there are other areas that will contribute to lack of oil pressure, but this is a good place to start. Before delving too deep into the engine, I'd at least verify the pressure with another gauge.

Ted E.