Packard Forum Index » V-8 (1955-56)

You're lucky. That is a simple roll pin. A small punch and hammer will drive out the roll pin. Then the gear with shaft can slide out of the pump.

The factory used a peened over solid pin that was not reusable. The roll pin is made of spring steel so it can be reused. Drive it in. Drive it out. for several reuses.

Just for entertainment value, | will throw in that the Melling pump has very nearly the same diameter shaft, within a few thou., and the same bearing length (2 inches) as the Packard, also no bottom bearing.

I have noticed when testing pumps on my rig that the vac pump adds a very considerable load onto the drive motor when present. This additional load may cause the rapid shaft wear so many have noticed. The drive shaft theory is also very intriguing.

But I would still love to understand the exceptions, like an untouched 104K mile 55 Pat I had a few years ago with oil pressure well above the center dot on the gage, and never a sound from the lifters, even after the vac pump portion later failed and started letting a lot of oil into the manifold.

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I don't think it matters as both Hash and Studebaker owners with Packard V8's also report poor oil pressure, and their pumps don't have the vac pump on the bottom. I had a '55 320 Hudson engine that also suffered from lifter noise and low oil pressure with the stock oil pump on it.

"I will throw in that the Melling pump has very nearly the same diameter shaft, within a few thou., and the same bearing length (2 inches) as the Packard, also no bottom bearing."

I'm not sure what Melling pump u r talking about. THe HEAVY DUTY Olds pump by MEllING et-al DEFINATELY HAS A LOWER BEARING. THe standard Olds pump by Melling and others does NOT have a lower bearing. It is the LOWER bearing that distinguisehes the HEAVY duty from the standard pump Olds pump regardless of manufacturer of the pump.

Not necessarily true. Remember Keith, when we were first working on this, we BOTH bought a "high volume" Olds oil pump, with the same part number, and the same Melling brand, and mine didn't have the shaft protruding from the bottom plate, and yours did? I may be getting old, but not that f'n old. Mine even had the "HV" tag on it, just like yours.

Hi, Eric,

Did your HV pump have an extended shaft captive in the bottom plate, just not extending through?

That is the design I used when improving the OEM Packard pump.

thnx, jack vines

Yes Eric. I remeber that bit of confusion we encounterd about the Olds pumps. However i think we had determined that the wrong pump was in the wrong box from the factory.


Jack. The Olds HV pump LOWER end of shaft is visible and one can see it turn. So it is not captive if that is what u mean by captive..

This tech discussion is well and good, but in my mind you guys are entirely missing the POINT.

The POINT is that the Melling HV pump has much more intrinsic pumping capacity than either the Packard or Olds standard volume pump. It's a volume issue! It is not a bearing issue or driveshaft diameter issue or anything else. It is a VOLUME issue.

Craig

Jack: no, it did not.
Keith: no, IIRC, we determined that it was from a different manufacturer in a Melling box. That's something to watch out for and Jack should put pictures in with the kit showing the correct pump with the shaft going through the bottom.
Craig: 100 percent right! I don't think it would matter either way, as we're dealing with a NEW pump, made from all new parts.

I agree that more volume will certainly help, but has anyone tested the original pump to see how much it actually displaces? My reference materials state that 3 to 6 gallons per minute is required to oil an engine.

After that, the primary cause of low oil pressure is going to be leakage either in the pump or elsewhere in the motor.

That's why I have asked the machinst working on this unit here to carefully look for any flaws in the castings and fixtures where leakage might be occuring.

The high variance among these engines is an area of concern.