Re: Packard TSB 56T-20 - Low Oil Pressure

Posted by Ross On 2009/11/1 16:18:55

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.