[rotorwrench]

I'm not as familiar with the engines prior to the 8BA so the oiling system may be a little different. I do know the 8BA has pressure feed to the fuel pump push rod that also leaks down into the rear cam bearing area. Since the eccentric is between the two rear cam bearing journals, it helps lube them both plus the splash oil from the oil pump drive and idler gears. That is why I don't eliminate the valley tube pressure from the equation. The rear cam bearings are not directly pressure lubed in the 8BA but they do have more than one pressure lube source. The source from the top of the pump to the gear compartment is also from leak by around the top of the oil pump body.

I'm sure they did this to keep oil pressure under control but still get everything lubed well.

Kerby