In Reply to: Re: Oil flow mystery posted by COLVIN on October 10, 2020 at 19:26:30:
You are correct. The oil pressure relief valve is used to limit pressure at cold startup when the oil is overly thick. Once the engine oil gets warmer viscosity decreases, oil pressure falls to something below 40 PSI, and the oil pressure relief valve closes and stays closed. It is next to impossible for an L-head turning 2000 RPM to generate 50 PSI oil pressure when the engine is at operating temperature.