Oil Pressure / Rear oil seal - Next step

[Mark Harrington]

Don & All,
I have done the following:
cleaned oil pressure regulating relief valve seat
Replaced oil 30 wt.
At 1600 RPM oil presssure 7 psig when at operating temperature
cleaned oil pressure regulating relief valve seat including using some carb cleaner
Replaced pressure gauge with a new one
Installed a stiffer spring
Added 10W 40 oil
At 1600 RPM oil pressure 7 psig when at operating temperature

When engine is is first started and oil cold pressure is is 35-40 psig then drops as engine warms up.

When warmed up 800 RPM oil pressure is 5 psig, at 1600 RPM oil pressure 7 psig, at 2400 rpm oil pressure is 9-10 psig.

Is there any way to confirm the oil pressure relief valve is not leaking?

What oil pressure is required for oil pressure switch to close and allow engine to run?

Engine runs and idles well without any unusual noise.

The rear oil seal at transmission output shaft has a slow but constant drip when engine is in gear. Could this cause the low oil pressure? I wrapped a 2' wide strip of white bed sheet around a rope tied it around the transmission case to confirm oil drip was not from the front of the engine. Are any special tools or techniques required to replace the rear oil seal? Should any other parts besides oil seal and gaskets be replaced during this repair?

Is there a way to determine if the low oil pressure is due to the oil pump or the bearing clearances? Can anything else can cause low oil pressure? Do you recommend replacing the oil pump components during an overhaul?

What is your recommendation on how to proceed from here to get the oil pressure up to the specified value?

Regards,

Mark Harrington