Ok guys – doing head job and rod bearing replacement on my Father’s 951, and can’t get any oil pressure on start-up. I have done the following:

Verified the torque on the Crankshaft Pulley Bolt.

Pulled the Oil Pressure Relief Valve and verified that it was free.

Checked the connections on the Oil Pressure Sending Unit.

Primed (or what I thought was priming) the Oil Pump, by removing the filter and pouring oil down the center passage until it filled.


We’ve cranked for several 5 second intervals and some 10 sec intervals with the coil wire off, and even popped the coil wire on until it was beginning to run (and promptly shut it down), but to no avail. When the ignition is turned on, the needle will rise to zero pressure, but no movement thereafter.

BTW, while the relief valve was out, we cranked it over and no oil appeared at the hole.

Is there anything I am overlooking besides a pickup related problem? I would REALLY like to avoid pulling the pan again until I’ve exhausted ALL other possibilities…

 

b u m p .

 

Keith, I don't know this for a fact but just turning the car over would probably not product readable pressure.

The reason I say this is after I change my oil and fire it up the gauge takes a couple seconds to get a reading. I replaced the oil pressure sender and has a second delay as well.

Good Luck

 

I'm inclined to agree with Fletch that you may just not be giving it time enough to fill the filter & build pressue in a dry engine. But, here goes....Hopefully someone will have "the" answer, but unless it comes along, I'd try the following:

Pull the spark plugas so the starter isn't working against compression, and can spin the engine faster.

Then crank it for 20-30 seconds & look for some small jump in the gauge. I really don't think this is going to hurt anything, since there are nearly no loads on the bearings in this state. You might squirt a few drops of oil into the plug holes to protect the rings.

I'd also consider using a mechanical gauge, but I don't know where you'd connect it, except in place of the sender.

Jim, back to "work".....

 

That might be the case - this car has been idle for almost a month since the bearing replacement, and has not been run for almost 3 months total...

I don't think it could get any drier than it is... I slathered abunch of assembly lube up in there, but I am NERVOUS about all the cranking!

I'm going to try to better prime the pump and give it a go again.

Have any of you guys heard of oil pump failure on these cars? I mean without FOD? I was under the impression that it was unheard of...

 

MISSION ACCOMPLISHED.

Well guys, too many of you responded to thank individually, but I want to express my gratitude for all the input I received on this situation. Many of you felt that I was not giving it enough time and you were right. Thanks for keeping me from tearing back into it, you’ve saved me a lot of time and effort. It seems the self psyche-out is still the most potent tool in my toolbox.

The method that worked for me was removing the plugs and DME relay and then spinning the motor for approx. 25-35 seconds straight, until the oil pressure needle started to bounce. I paused and repeated, and got 2-2.5 bar on second try, buttoned her up and fired her up! No problems so far…

Another method that was offered up REALLY caught my attention – using a Mighty-Vac to suck oil through the block to the Oil Pressure Relief Valve to prime the system. This seems brilliant to me, unfortunately I could not get it to work in this situation. I feel that this is probably a superior method, however, and will try it again next time I do rod bearings.

Thanks again for the inputs and reassurances. Once again, the online tech list proves its value.