I have done several things to no avail. I first removed the oil bypass to make sure that there wasn’t anything between the ball bearing and seat- clean. Then I cut open the oil filter to be sure there was no metal indicating shredded gears -clean.
Then I installed a mechanical oil pressure gauge. When I started the engine, the oil psi was around 55, so I thought it was resolved. When full power was applied for takeoff and about 20 feet AGL the oil pressure went back to 20. I landed immediately. But once on the ground and at idle, the oil pressure went back to 55. I’m baffled.
SD