Packard Forum Index » V-8 (1955-56)

Apparently, Packard engineers felt a second source was a good idea - enough that they added the balancing valve for a vacuum pump piggybacked on the oil pump. The idea behind it all was that as engine demand increased, manifold vacuum feel off, but as engine RPM increased, vacuum generated by the oil pump set-up would increase.

While AM engineers opted for their own oil pump for the Packard V8 installation, sans vacuum pump, they also used vacuum-driven wipers motors. Apparently they liked the balancing act, too, but turned to a dual-action fuel pump as the secondary source.

A 20K lifespan doesn't sound too bad on a car that isn't driven on a daily basis, yet I wonder if that's due to tired old rubber. As BigKev showed us in his article, the dual-action pumps aren't terribly hard to rebuild.

As for authenticity, I've seen more than one V8 Packard at a club show that was refitted with dual-action fuel pump to accommodate for retained vacuum wiper motor when the PI-modified pump was added.

Brian, have you been into the Old Harper again?