Packard Forum Index » Pre-War (1899-1942)

My mistake with a poor explanation. The mechanical fuel pump on the motor was working fine as far as I know and I only switched the back-up electric pump on during long hot days in slow traffic ( ye olde vapour lock, etc.). Actually when the pump arm is under the cam lobe, the cam lobe gave it very little grief. I was just not believing of the fact that you would have to instal a fuel pump with the cam lobe in the operating position and then have to compress the pump to get the flange onto the studs. I shall bend the arm to the correct position when I find out the correct position of same.

View of 1936 Twelve fuel pump installation from one of the original Packard engine blue prints. Should there be any doubt about the positioning of the arm with respect to the cam lobe this should answer it. Twelves 1933 thru 1939 all use the same fuel pump (AC#1778).

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The two pump photos are not exactly the same size and angle to overlay them perfectly but offhand it looks like bending the arm to remove that first curve thus making it straight from the pivot to the cam pad would make things fall into place. I'd be curious in how it got bent in the first place or is that the proper pump.

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Congrats, nice piece of work superimposing the two photos!

Excellent work on the photos. My pump is a 1778 which is correct for a Twelve. No idea as to why the arm is different, although it appears to have a different part number to the arm photographed by Dave. I shall bend the arm into shape using the superimposed photo as a template and see how it performs. Thanks for everyone's help and I shall report back on the results. PT

Since I've never worked on anything so lofty as a Twelve, this is well beyond my expertise but could it be that the arm was installed upside-down when the pump was rebuilt?

Don, if you take a close look at the shape of the "pad" at the end of the arm that wipes against the cam you'll observe that it is installed correctly.

Hello all, I need to alter the actuating plane of the pad of the arm in relation to the operating cam as illustrated in the accompanying pic of the Pad. It is quite shallow at the moment. I shall bend the arm approx 250 thou to the right to make a sweeter alignment of pad to cam...at least that is the theory. PT

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That pad is pretty abused & probably should be resurfaced, have you taken a look at the cam lobe?

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Looking closely, O_D is correct; the latest picture confirms this. It's absolutely mystifying.