[Clyde]

When I managed a hi-performance automotive machine in the 70's we primed every engine that left the shop. On that note while priming whether by an auxiliary pressurized oil tank or spinning the oil pump, on certain engines you have to also rotate the engine by hand. The reason being, some engines feed oil to certain parts of the engine occasionally, so the camshaft might have a flat in a cam bearing journal, this is just one of several ways oil is fed to the top end of an engine.