Oil Pump Prime Procedure

Yup. Brand new one. The large O-ring under the cover was pressed flat with no rebound. Same with this one and the other small one inside. I pulled the oil sending unit this afternoon and it looks like oil has not been up that far. But it has been sitting for two weeks. I expected to see some evidence of oil. Put a flex line down the hole about 4-6 inches and no restriction. The sending unit has been replaced probably by the PO trouble shooting why the gauge does not register. I got nuttin' on why oil would not travel up there to the sending unit if that's the case.

Putting it all back together now and hoping I have a working pump and quiet lifters. The shaft is back in the position it was before and verified with the distributer rotor position.

This engine has over 100K miles on it. Probably closer to130K. Not an oil burner but fellows that have followed behind said they could see little whiffs of smoke when I let off the pedal. Indicates the valve guides are worn. I believe a rebuild is not too far away. Certainly valves and hardened seats so I can quit using lead additive.

If you aren’t getting pressure priming the pump it might be a waste of time to reassemble.

Maybe put a new pump on it.

OKDart said:

If you don't have a gauge, maybe crack the pressure switch loose a turn and watch for oil leakage, that'd be good enough.
Also one oil pump gasket kit had a paper gasket without the hole for the pickup (used on external pick-up pumps), I think that issue has been resolved for a couple years now, but something to watch out for.

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It was Milodon, I discovered it the hard way a couple years ago. They put the gasket for an external pickup in the standard kit. It was painfully obvious when I took the pump back off. I cut the gasket around the pickup port and reinstalled it and the pump. After spinning the pump a few revolutions with the priming tool, it had great oil pressure. When I get on my desktop computer a little later tonight, I’ll post up a picture.

Before: you can see where the port is supposed to be located


After: with a hole cut to accommodate the pickup.



The stock gasket has a much larger center hole.

It's visible in post # 60.

I've seen worn out pumps that lose prime. They're just. Worn

Pull the oil filter off and spin the pump with your drill motor. You'll know very quickly if it's pulling oil or not....just have some rags handy!

Wish I would have thought about pulling the filter. Instead I removed the gauge sending unit and tried installing a fitting and clear tube to observe if oil was getting to that area. The sending unit strangely does not show evidence of oil ever being there but it's been a couple weeks since running. Poked a small flex line down the hole about 4-6 inches and no resistance so I don't have any idea what is going on there. But after priming I thought there should be something on the sending unit. Could not get a fitting installed into that tight spot so reinstalled the sending unit, primed one more time and installed the distributor. Fired the engine up and heard lifter noise for about 4 seconds then all was quiet. That was good to hear and I called it quits for the day. Will drive it today. Took a picture of the gasket (MAHLE) that I used and tried to post it but I'm having issues with transferring photos. It is the larger cutout though.

Thanks to everyone for helping me on this journey. I learned a lot and maybe others will as well. Sure hoping I'm done with this.

Mariposa Mike said:

Wish I would have thought about pulling the filter. Instead I removed the gauge sending unit and tried installing a fitting and clear tube to observe if oil was getting to that area. The sending unit strangely does not show evidence of oil ever being there but it's been a couple weeks since running. Poked a small flex line down the hole about 4-6 inches and no resistance so I don't have any idea what is going on there. But after priming I thought there should be something on the sending unit. Could not get a fitting installed into that tight spot so reinstalled the sending unit, primed one more time and installed the distributor. Fired the engine up and heard lifter noise for about 4 seconds then all was quiet. That was good to hear and I called it quits for the day. Will drive it today. Took a picture of the gasket (MAHLE) that I used and tried to post it but I'm having issues with transferring photos. It is the larger cutout though.

Thanks to everyone for helping me on this journey. I learned a lot and maybe others will as well. Sure hoping I'm done with this.

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I’m not trying to be a ********, but you didn’t learn about the importance of a working oil pressure gage.

Definitely. But since purchasing this car one year ago I've been fighting gremlins to include tires and wheels, a complete brake rebuild, finding shorts in wiring and having to remove the interior to find them, along with various oil and anti freeze leaks. The EL lighting does not work but the temp, alt and fuel gauges do. Figure this winter will remove the cluster and send it to the man on this forum that does those. Thought it was the gauge but it might be something in the engine preventing oil getting to the sending unit. Further to follow and in hindsight.......well somebody saw this chump coming. One thing at a time.

@Mariposa Mike - When you were trying to ‘prime’ did you turn the drill COUNTER Clockwise?

Yes I did. I was warned/advised by others to do that. And good they did. I would have gone the other direction.

If you're replacing the pump, simply submerge it in a bucket of out and use a long Allen socket on a ratchet (air or battery) and spin the pump shaft.

Wipe the oil off he outside of the pump and bolt it up.

The pump will immediately start pumping oil (provided there's oil to pump in the system) and you won't have to mess with removing gears from the engine and screwing up the distributor timing.

For those of you reading this that have internal (inside the sump) oil pumps, you don't have to bother wiping the excess oil off it.

Filling the oil filter before installing it will speed up the system pressurization process, too.

The only times I've ever "primed" a lubrication system on a completely assembled engine, I always use an external (electric, usually) pump and induce the oil into the block via the oil sender hole using a T fitting.

A bit off the topic, but another use for a pre-lube system is:

A motor-driven pre-luber is great for adjusting valve lash on hydraulic lifters as well.
Set the crank at TDC on # 1 and with the rockers adjusted loose to allow the plunger to rise to the top against the retaining ring simply turn on the electric pump and pump up the pair of lifters then adjust the preload. Rotate the engine 90 degrees and do # 8, Another 90 degrees and do # 4, etc.

Rotating the engine a quarter turn at a time to get each pair of lifters at the base circle of the cam exposes the oil feed hole in the lifter to the pressurized oil in the lifter alley.

Depending on your cam specs, the lifter preload is anywhere between 0.020" and 0.600". Using the pre-luber to pressurize each pair of lifters gives you the ability to get the preload as accurate as possible.

To little preload causes noisy lifters but the engine will really rev high.
Too much preload will result in pumped up lifters in upper rpm ranges resulting with really poor time slips.

I've been adjusting the rockers on my GTX this way since 1969 when I installed a set of stage III rockers and pushrods. Valve float was substantially reduced once the hydraulic lifters were tuned properly.

Good to know these methods. I have a rebuilt 413 that I can pre-lube before starting. Trying to imagine what you used for an electric motor pre-lube tool. Is it something you made or is it available on the market somewhere?

I have a fairly high volume $23.00 battery operated pump that I use to empty oil pans and such but it overheats if it sees too much pressure. I just emptied a 275 gallon fuel oil tank with it a couple of weeks ago but I had to stop frequently and let it cool down.
https://www.amazon.com/dp/B08GLVM2ZZ?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4




I have a couple of purpose-made pre-luber systems that were manufactured in PA decades ago but I think they've gone out of business or are selling the more common one-use pressurized canister systems like the ones you can buy from International to pre-lubricate a new engine.
Their original systems were designed to automatically turn on for 5 seconds or so every time you turned the key prior to starting the engine. I bypassed the time and used a toggle switch


One of the aforementioned pre-lubers resides in my '48 Chrysler and I've been using it for close to 39 years EVERY time I start the engine if it's been shut off more than a couple of hours because the twin oil filters (an Andy Granatelli product) are mounted right up next to the left hood hinge and since they're horizontal they partially drain back into the block. There's also an oil cooler on there as well and that old side-valve six is too rare to risk starting it w/o any oil in the system for a critical cold-start scenario.

I push a momentary push-button switch and watch the oil pressure gauge. When it comes up to mid range, I take my finger off the button a n press the starter button.

Here's a video of a home made system based on the ones that I bought decades ago. To do lifter adjustment, you need to be able to switch the pump on and off at will and this fits the bill.

Mariposa Mike said:

Yup. Brand new one. The large O-ring under the cover was pressed flat with no rebound. Same with this one and the other small one inside. I pulled the oil sending unit this afternoon and it looks like oil has not been up that far. But it has been sitting for two weeks. I expected to see some evidence of oil. Put a flex line down the hole about 4-6 inches and no restriction. The sending unit has been replaced probably by the PO trouble shooting why the gauge does not register. I got nuttin' on why oil would not travel up there to the sending unit if that's the case.

Putting it all back together now and hoping I have a working pump and quiet lifters. The shaft is back in the position it was before and verified with the distributer rotor position.

This engine has over 100K miles on it. Probably closer to130K. Not an oil burner but fellows that have followed behind said they could see little whiffs of smoke when I let off the pedal. Indicates the valve guides are worn. I believe a rebuild is not too far away. Certainly valves and hardened seats so I can quit using lead additive.

Click to expand...

You probably should have opened up the pump and verified that the clearances are in spec. That would have also been the perfect opportunity to “prime” the pump with assembly lube.

It sucks not knowing the history of the car, it could be just plain worn out or some ham handed mechanic screwed something up.