Help! No Oil Pressure

Gerry Dz · 06-23-2003, 12:28 PM

I am in the process of building a 951 motor from the ground up. It is finally in the car after approx 2 years and upon cranking it for the first time, I can not get the oil pump primed. With the filter off, I am not getting any flow to it. I have cranked it for a few minutes already. Before I start to take things apart, I wanted to see if anyone has had issues with priming the pump. Are there any good suggestions on getting it primed?

Lawrence Coppari · 06-23-2003, 12:34 PM

When I did the rod bearings on mine I also replaced the oil pickup with another longer one that gets closer to the bottom of the pan. Well, I took the plugs out and cranked and cranked. No oil pressure. So I said the heck with it and just started it. Pressure came up and all is well thousands of miles and 8 track events later.

Scarey though. Don't know why mine did that. Wonder if you could apply a little positive pressure at the dipstick tube with a very low pressure air hose. I just do not know. I should have tried that but did not think of it at the time. Whether it'll do anything or not, I don't know.

I assume your crank pulley is tight.

Britwrench · 06-23-2003, 01:20 PM

Try overfilling the oil pan by two or three quarts, this helps the oil pump pick up. Once you have pressure correct the oil level.
Also pour oil down the oil filter housing. Crank the engine over with the spark plugs removed and the DME relay out.

Lawrence Coppari · 06-23-2003, 02:03 PM

Sorry forgot to mention I had the DME relay out. Good point Britwrench.

Gerry Dz · 06-25-2003, 05:59 AM

One of my attemps was to put in an extra 6 qts. oil, I then rotated it 6 revolutions by hand. I then brought it back down to the proper level. It still didn't prime. I have borrowed a vacuum pump from a friend and will pull a vacuum on the outer oil challel where the oil filter mounts. In looking at my old block, I think that this is the oil pump side, but will double check. I will let you all know how it goes

Britwrench · 06-25-2003, 06:10 AM

Cranking the engine 6 times by hand won't do anything!
You need to crank the engine with the starter until oil pressure is seen on the gauge, this may take 30 seconds or more.
Overfill the engine again, pull the spark plugs, pull out the DME relay and crank away. Once you see oil pressure on the gauge set the oil to the correct level.

Gerry Dz · 06-25-2003, 06:18 AM

I'll give it a shot this PM thanks!

Lawrence Coppari · 06-25-2003, 07:18 AM

No wonder I never got oil pressure in mine by cranking after I changed the rod bearings. I only cranked for about 10 seconds and gave up.

Gerry Dz · 06-25-2003, 12:02 PM

OK - I put in 3 extra quarts of oil and cranked for 30 seconds four times. Still nothing.
I also tried to pull a vacuum and it didn't help. Should I still keep cranking??

I may try to prime it with a pressure pump thru the oil pressure sending unit tomorrow.

robm-951 · 06-25-2003, 12:28 PM

Quote:

Originally posted by Gerry Dz
OK - I put in 3 extra quarts of oil and cranked for 30 seconds four times. Still nothing.
I also tried to pull a vacuum and it didn't help. Should I still keep cranking??

I may try to prime it with a pressure pump thru the oil pressure sending unit tomorrow.

Did you try and pour oil down the center of the oil filter mount? Try this and crank for a while. When we replaced the rod bearings in my nephew's car, it took forever to get the oil pressure to come up. If I recall correctly, we primed it like I said, cranked if numerous times with the DME relay out, ( I think at this point, you could just barely see the oil pressure needle jump), then finally just went ahead started it and let it idle. The oil pressure did come up after a good 20~30 seconds of idling.

Good luck with it,
Rob