Finallly got oil pressure, maybe I'll sleep tonight.

[terry.mortimore]

Hi gang:

I'm working my way to first engine start and have been turning the engine over with the starter and was not getting oil pressure or flow.

I have a O-320 with a Superior cold air sump that I assembled about 4 years ago. Reading through the archives here told me about a oil plug that needed to be removed when using the Superior pump. I could not remember doing this and was really starting to doubt myself.

Also read about pulling a vacuum on the oil pressure sending port to help prime the pump. I went to the hanger early this morning to try that trick, but was fully expecting to pull the sump off and look for that plug.

Much to my relief the vacuum trick worked, I started to see oil coming out and when I used the starter again pressure started to build. The vacuum was enough to prime the pump and away she went.

It now shows 50 psi when rolling over on the starter.

When my prop arrives next week I'll be ready for first engine start! I'm a happy camper now.

The wisdom on this forum is invaluable, Terry

[lr172]

For others, a trick that I learned in my auto days was to put a fairly generous amount of assembly lube the oil pump. The grease helps to create the initial vacuum for the initial prime. I had oil pressure in about 30 seconds of cranking or so.

Larry

[Rupester]

It's also common to have an air lock in the small oil hose that goes to the sender. I had to loosen the connection while cranking a few times to purge the air. Three seconds watching apparent zero oil pressure feels like 3 days!

[snopercod]

Originally Posted by lr172

...generous amount of assembly lube the oil pump.

Lubriplate?

[8 ball]

Plus 1 for what Larry said.

[tim2542]

Originally Posted by lr172

For others, a trick that I learned in my auto days was to put a fairly generous amount of assembly lube the oil pump. The grease helps to create the initial vacuum for the initial prime. I had oil pressure in about 30 seconds of cranking or so.

Larry

Pour some clean oil down the oil cooler "Out" line (back towards the pump), the port is right at the back of the pump and will flood the pump.
Re: another post, an air lock in the sensor line is a non issue, pressure will be pressure whether air or oil.
Tim Andres

[azrv6]

Terry, how did you apply a vacuum to the oil pressure line?

[Jesse]

I'd like to know as well. Thanks in advance for sharing.

[terry.mortimore]

Hi guys, I hooked a 6 foot length of 5/16" clear tubing to the oil pressure port.

I hooked the other end up to an old vacuum cleaner that I have, sealed it up with electrical tape. The vacuum cleaner hose had an adjustable opening so I could throttle the amount of vacuum.

Turned the vacuum on and watched the clear line for signs of oil, it took about a minute to appear. Unhooked everything and tried the starter and oil pressure started to build, took a few moments to build to 50 psi.


Terry.

[Rupester]

Originally Posted by azrv6

Terry, how did you apply a vacuum to the oil pressure line?

I just loosened the connection at the sending unit and had someone turn the engine over just a couple times. Cranking oil pressure pushes the air out of the line... and quickly. If you crank very long you have a mess in no time!