Re: 12 volt battery cables as a auxiliary engine to frame ground?

Posted by HH56 On 2020/3/13 15:53:50

From what I can find, the extra ground connection Packard installed near the transmission on prewar cars was apparently needed because the under seat battery ground cable was connected directly to the frame and the second large ground strap connected the frame to the engine. They seem to have stopped using the extra ground strap with the relocation of the batteries to the engine compartment where the battery ground cable could connect directly to the engine.

Until 1955, the only aux postwar hard ground connection appears to be a small 14 ga wire connecting the generator case to the fender and continuing on to the regulator. That ground wire was needed for a solid voltage reference between the generator and regulator. It seems the accessories and lights -- actually anything mounted on the frame or body -- relied on that wire plus whatever metal to metal connections in linkages and tubing there was between the engine and frame for their grounds. For 55-56 they added a short approx 8 ga strap between the R head and body.