You may have air in the gauge line. Remove line from bacj he guge and stat ngin o pump i out. (amd oil)

Gene, correct me please if I'm wrong but to the OP I believe he meant to say ".....from back of the gauge and start the engine to pump it out (and oil)".

Air in the line to the gauge does not matter. It will read the pressure with either oil or air. Air is preferred in the line as it does not delay the reading.

Your problem is probably too large a gap inside the pump for the vanes to pickup the oil from the pan. Adding oil to the pump output can give enough seal in the pump so it pumps oil.

Thank you all for the replies. I remember when I put the oil pump back together I had a damaged gasket, so I made a replacement with some gasket material that was slightly thicker than the original. So that may be causing enough space inside that the gears of the pump are not picking up the oil. Looks like I might be dropping the pan to try to fix it.

I make the gaskets from computer printer paper. I would first try to see if I can get some higher viscosity oil into the pump to see if that gets it primed. Might have to do it after oil changes or long time without running.

@ralph-c-vemmer often when I dismantle a oil pump as I reassemble it I use a heavy smear of light grease, this makes a definite seal between all parts before the oil actually gets to the gears.

Tony

Thanks, Tony and Chip.  Years ago, I used Vaseline and packed it in the gear cavity on other cars.  It picked the oil up right away.  I will try a higher viscosity oil first to see if that works.  Am I correct in using the oil line to the valve rocker shaft as being a good point to pour oil and get it down to the pump?