I played around the past few days with oil and psru. I added a psi gauge on top of psru,and vented the housing back to the oil dipstick tube. I have an oil breather tube from the fill port. We should have a vent on the oil crankcase. Without it, I did a pull and turned off the engine and 5psi stayed within the system until I cracked open the dipstick to relieve the pressure.
On Neil's PSRU, the oil inlet is on the front half. The front drain is on the side, which connects to the back drain that is an10, then to the oil pan.
Anyways, the stock psru inlet restrictor was 9/64. Once warmed up and running at 2200rpm static on the ground, engine oil is about 100psi for me. PSRU pressure was about 2.5psi and lots of oil was venting back into the oil dipstick tube. I kept on sizing down the restrictor until 1/16th. That mostly kept the vent clean and clear of any pressure build up inside the psru.
I'm not sure why Tracy recommends having the psru fuel of oil, maybe uses different bearings then Neil's? From a truck gear case perspective, plantey gears only need a coating of oil, not full and pressurized. I'm probably wrong, but throwing it out there. ?.?
- Matt Boiteau