Packard Forum Index » V-8 (1955-56)

Hello all. I just had the Jack Vines Oil pump upgrade and she sounds great- no lifter noise. The car is a 55 Model 400. Before, the oil pressure gauge would register on the center line or a bit below when warmed up. Now it registers at about 2/3 to the right.

I spent a lot of money having all the seals replaced. The car has no leaks and I'd like to keep her that way. I am using 15-40 oil now. Should I use a less viscous oil to get the pressure down a bit? I have heard the oil pump upgrade can result in blown out oil seals- thanks MC

Yes, definitely go down to at least 10W40 and 5w40 would be OK.

jack vines

2/3 to the right is insane oil pressure on an OEM gauge. Probably like 80 PSI.

If the overall engine wear is low then I don't see why even 10W30 wouldn't be OK as that's what these cars used new.

Thats where mine is highway.

Idle center..+

I just started using this..

I have a few thousand on my melling..

Attach file:

---

  20250412_152801.jpg (3,414.53 KB)

Thank you for the responses. I will do as you suggest. I did not do the rebuild, but I think it was a good one as the motor runs very strong

The Melling M-22F AND M-22FHV pumps both come with a standard pressure relief valve that opens at 50 psi.
There is an optional spring for the relief valve to make it open at 65 psi.
Unfortunately Melling does not have the nice charts for these pumps that they have for their high performance line of pumps.
You may want to put a pressure gauge on and get actual pressure numbers. Knowing provides much more peace of mind than guessing.

I switched to 5w 20 hoping to get the oil pressure down. Now the gauge is dead center or a bit to the left at idle or around town. At 65mph on the highway it is 2/3 to 3/4 to the left.

Nothing leaking, I'd like to keep it that way. Runs so good it is hard to believe.

Comments welcome.

Forgive my ignorance, but how would I hook up an oil pressure gauge ?thanks MC

Best advice requires knowing specifically which oil pressure gauge.
Electric or mechanical reading? Each requires a very different hookup.

jack vines

Quote:

Curious what you would advise as I would always use the ports directly at the top of the first oil passage, in the valley pan, by the distributor.

I know there is at least one more in the passenger head rear which is the symmetrical port for the oil filter feed in the driver head.