Finished a complete rebuild. Everything cleaned, heads machined, new valves and guided. Reassembly went as planned. Mated engine to transmission on a test bed. Hooked up starter to battery and a start button (no spare plugs). The goal is to get oil moving periodically while awaiting completion of body restoration.
I was pleased to see 55psi on a mechanical gauge on the first four weekly cranks. Compression is also solid. However, I lost pressure. I decided to replace the stock oil filter with a new spin-on filter adapter (SNG). Oil looked clean. Some fine particles in oil, but I would expect some on initial startup with new rings and bearings. Crank turns smooth using breaker bar. Still no oil pressure with new filter adapter.
Question, what is the best next step in my search for oil pressure?