All my engines have gaco type seals on the cranks which means the normal metal sealing glands are replaced with a plain aluminium bronze thrust washers. As the pump is quite capable of delivering oil at considerable pressure, I have seen 90 psi against a dead head, the thrust washers are recessed by .015″ on the oil delivery side out to about half the distance to the OD with three radial V grooves filed in about 010/015″ deep to the OD This then acts as a non return system as well as floating the cranks on a film of oil at the thrust washers. Very straight forward and very reliable. Not suitable for drip feed systems.
