In Reply to: No Oil Pressure posted by Jim Rushford, CA on August 16, 2019 at 22:30:33:
Fully rebuilt by a shop and 20 hours or less of run time. How many calendar days is that and what is the warranty on the shop's work? My first inclination is this is the engine shop's problem not yours.
That said, a sudden and total loss like that makes me suspect the pickup tube. There have been cases of fresh overhauls where the crank was rubbing on the tube and wore a hole in it but I would expect some noise from that.