Packard Forum Index » Post-War (1946-54)

I recently purchased a 1951 200 from a nearby used car dealership. The car ran, albeit poorly, and I've only now started working on it. The car only had one owner prior to the dealer, and the dealer purchased the car from an estate sale. The dealer said that he had just put in a new 6 VDC battery in the car the day before.

Today, I noticed that battery was installed with a negative ground. It's still a 6 volt system, and it appears that all electrical components are original.

My question is how could the car have been running? It appeared that the coil was wired up for a conventional positive ground, although I had removed the coil and distributor prior to seeing if they were wired correctly. Also, the fuel and temp gauges and lights all also seemed to be functioning.

Unless something has been modified to use a solid state replacement component, nothing in the car is polarity sensitive except the radio and even that depends more on internal polarity after the vibrator, transformer and rectifier tubes so depending on how those are isolated, it may even work.

The spark will be a little less efficient with the coil backward and the generator only needs a quick polarizing to work properly and time would probably take care of that. If you had an ammeter, that would have read backwards but still worked. Gauges are all bimetallic, so just rely on a coil heating up.

My '50 came with a new battery that was installed with a negative ground. The car ran but the Amp gauge read backwards (showed discharge when in fact it was charging) and the radio just buzzed. I reversed the battery, repolarized the generator and now the radio plays as it should and the amp gauge is reading correctly.

Unless you're planning on adding non-authentic electrical accessories that require negative ground, there really is no advantage to having it; if that's the case I'd return it to the correct positive ground.

I restored it to a positive ground, and the difference was pretty remarkable. It runs infinitely better than it did before.

Thanks guys!

The improvement no doubt due to the fact that when the battery was put in backwards, the coil polarity wasn't changed to correspond.