Intermittent Oil Pressure

Hi all,

New to the forum. Looking for help on my 68 Valiant. It has intermittent Oil Pressure.

The motor I have in it is a ~76 bottom end, with a 68 head. It also has the 68 camshaft in it. Before I put it in, I put new bearings and rings in it.

After I put it in, I had good oil pressure, 20psi at idle, 60psi at high revs. After a little running, the oil pressure dropped out, showing nothing at idle,, and only about 30psi at high rpm. It will even knock sometimes at idle. However, sometimes the oil pressure would suddenly fix itself, and be 20/60 again.

I pulled the motor and replaced the pickup, and the oil pump wondering if something was wrong with oil pickup. I couldn't see anything wrong in the bottom end, so I put it back together. However, I still have virtually no oil pressure.

Anybody have any ideas? It acts like there is a leak in the system, but I can't figure out how it sometimes stops leaking and has pressure again. Thanks,

Grant