I, too, am having oil pressure problems. It's in my 1977 Sterling that has a 1915 cc. VW engine set up the same way as in a KR.
I had to rebuild the engine. I pulled the plugs to do a compression check and learned the hard way that someone had put plugs with one inch of thread on them in heads designed for the plugs with 1/2 of thread. The carbon built up on the extra threads and installation without NeverSeize boogered the threads on both heads, so I rebuilt it with new heads, jugs, pistons, rings, and bearings. The oil pressure before I overhauled it ran around 55 psi cold and 42 fully hot at 3000 rpm. Idle pressure was around 15-20 psi hot. The engine sounds fine and runs well. However, the oil pressure is low: about 35 psi when hot at 2500 rpm and drops below 10 at idle. I'm beginning to suspect that the pressure relief valve near the pump is hung up and not closing fully. I removed the spring, put the plug back on and turned the engine over to get the oil pressure to pop the piston down. It doesn't seem to be galled, but it still has low oil pressure when I started it again. This engine case has a pressure relief valve near the oil pump and a pressure control valve near the flywheel. I was careful that I didn't mix the pistons and springs during teardown. The relief valve has a pretty heavy and long spring. The pressure control valve has a short and much weaker spring. Any suggestions as to where to start trouble shooting? Although the pressure gauge varies with rpm and oil temperature, is it possible that I have a bad sender unit? Does anyone know the distance from the bottom of the relief valve piston and the outside edge of the hole? Any suggestions will be greatly appreciated. Jim Vance va...@hbcomm.net
