Excessive Oil Pressure

[zav6a]

My hanger mate is getting close to starting his 0-320. It is a wide deck, 150 hp version. It is a dynafocal mount and is not set up for a governor adaptor but other than those clues, I cannot say what model it is.

By simply cranking the engine with plugs out, it generates excess oil pressure. Blew up two oil coolers before he figured it out. After much investigating, we found that the port to the sump from the pressure relief valve is blocked. Safety wire will head down about 8 inches.

Any ideas where the blockage may be occurring? Is there a gasket surface somewhere along the return that may be mismatched?

[MarinePilot]

If you have the oil screen, check the gasket between the screen housing and accessory housing. The gasket may have been installed incorrectly, causing the small hole to be blocked causing high oil pressure.