Expert: Brad Sears - 10/1/2008

Question
QUESTION: Greetings,

My car make is as follows;

1952 Cadillac 626
V8 313 (I believe) We rebuilt it.
6 Volt electrical system.

History:
I purchased this vehicle about 4 years ago. We rebuilt the engine, replaced
exhaust system. Gas tank replaced. Some electrical wires replaced. Exchanged
the generator for an alternator for 6 volt system.

Symptoms/Problems:
I would drive for a day or two and the battery would run low. I thought it was
because of the generator. I talked to a mechanic the other day and he told me
that the 6 volt system had reversed polarity. If I had it reversed, it would still
run but the battery would run down.

Question:
If I reversed the wiring, (positive to frame-as ground) would this do any
damage to the battery? Would the alternator be affected?

Thanks,

Charles

ANSWER: If you reverse the battery leads on the car the alternator will direct short circuit through the diodes. You need to do some voltage testing to make sure that the alternator is putting out and you need to have your battery load tested. Keep me posted.
Brad

---------- FOLLOW-UP ----------

QUESTION: Brad,

Thank you for your response. A follow up question. Do you have any
knowledge of the history of this Cadillac and if the system came with reversed
polarity? If it did I would change out the alternator for the generator and
reversed it. Or do you think it is better to keep the alternator? I tried to keep
this as original as possible. Thank You again.

Charles  

Answer
Now this is only my opinion so do not rate me as a moron for my answer. If it was my car I would do everything I could to get the alternator working. An alternator will provide a more reliable voltage stream at lower engine speed than the heavier larger DC generator. However if you are concerned about show points and originality then use a generator. The 1952 Caddie was a neg ground. Cadillac stopped the pos ground in 1946.
Brad