Packard Forum Index » V-8 (1955-56)

Well.... it didn't sound like a fuel pump problem to me but I'm so glad you did the pressure test as earlier suggested, looks like you've found a major problem, those pressures are inadequate. It could be the pump spring, could also be a pair of valves that are leaking and allowing the fuel to "short circuit" between the outlet and back to the inlet. Looks like a fuel pump kit or professional rebuild is in the cards.

Chilton's manuals are very good, I have one for the 20s and early 30s cars that I use regularly. Another seldom seen but excellent one is Glenns, not so much for specifics but it's just great at teaching general principles.

There may have been some mitigating factors here. When I reached down to un-fasten the inlet hose I found that the clamps weren't much more than finger tight. Plus I could spin the washers on the two bolts holding the pump to the engine block - lotsa room between the bolt heads and the block.

I decided to pull the pump off for a closer inspection since it was almost off anyway. I've got a spare kit from Then and Now so I may rebuild the pump myself - OR - take the advise of (I think it was) Packard V8 and get the Ford pump. Summer is drawing to a close and I'd like to get some driving in before the Monsoons hit here in Oregon.

Rebuilding the AC pump I have sounds like a good Wintertime project.

Try to tighten everything up, and maybe it will be ok. You got nothing to lose!

It is a good idea on the '55 V-8s with the small spark plug brackets to separate the wires for #5 and #7 (2 rear cylinders on LH side) by placing them on the outside receptacles of the brackets and placing the wires for #1 and #3 be on the inner two. Do this on both brackets. The better solution is to us the '56 wire brackets, which are much wider.

(o[]o)

Edit: Here is a photo of how I did it on my Clipper.

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Jim L, I recently rebuilt my '56 Pat pump using a Then and Now kit and I can assure that if you go carefully and follow the instructions, it is quite easy to do and the results for me were great - a vast improvement. One of the inlet pump valve discs had come loose and I was experiencing fuel starvation due to poor sealing, but no problems at all now. Regards, John

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Hi everyone, here is an update. I took a couple of days off for perspective and avoiding the 95 - 100 degree heat wave we had.

Big Kev suggested that I be sure that the ceramic fuel filter was completely clean was a good tip but I applied it in a way neither of us intended. When I took the glass bowl out I was so intent on not dropping the filter that I dropped the bowl (expletives deleted). Fortunately, I had a spare bowl from the parts carb. Unfortunately it was the short bowl and I had no filter for it. I put it on anyway since NO filter would certainly eliminate any filter blockage. She started right up and my smooth idle was back but a test drive taught that the bucking problem was still there. I then rebuilt the fuel pump using my spare kit from Then and Now as John suggested. I tested the pump afterward and it produced a good strong fuel flow. Took the test drive and nothing changed. Still the bucking at constant speed so I gotta say O_D was right about the fuel pump NOT being the main problem.

I've now got two ideas to run past you all:
One is that the fuel tank I got from Mike Dulinski was professionally treated by the company that was all the rage two years ago and whose name I can't recall at the moment. Has anyone had any problem with the coating coming off inside the tank? The car was at a steep angle when loaded onto the flat bed truck and I'm wondering if the "wave action" could have caused some chunks to come off and occasionally block the outlet. My only problem with that is that the bucking occurs only at constant speed. If it were blockage I'd think I'd have problems over all speed ranges.

Idea number two: I think it was O_D who suggested testing the vacuum advance. I couldn't find my hand held vacuum pump so I took off the distributor cap, hooked up a length of hose to the vacuum line and sucked. The vacuum advance - advanced. However since the bucking increases in severity with increase in mph, I'm wondering about the centrifugal advance.

What say you all to that? If that is a possibility, how does one go about checking that out? I really hate removing the distributor but not as much as I hate not being able to enjoy my Packard.

If anyone has any other ideas PLEASE bring them on!

JW wrote:
It is a good idea on the '55 V-8s with the small spark plug brackets to separate the wires for #5 and #7 (2 rear cylinders on LH side) by placing them on the outside receptacles of the brackets and placing the wires for #1 and #3 be on the inner two. Do this on both brackets. The better solution is to us the '56 wire brackets, which are much wider.

(o[]o)

Edit: Here is a photo of how I did it on my Clipper.[/quote]

Thanks John, I took your advise and moved the spark plug wires as you suggested and did notice it helped smooth out the engine at idle.

As a side note; Took the '51 200 Deluxe on a 29 mile round trip to Gresham (town east of Portland) in 87 degree temperature partly in stop and go traffic due to construction. Just got back. It ran flawlessly with the temp gauge barely over mid point at the most when caught in traffic. She withstood the trip better than I did.

If I could only get the '55 sorted out!