Classic/Antique Car Repair: 1948 Chevrolet Fleetline, 1948 chevrolet fleetline, gm cars

Question
QUESTION: Hello,

I have a 1948 Chevrolet Fleetline. This car has been sitting for five years so of coarse my battery is bad i went out and bought a new one charged it and the car fired rite up. I had it sit and run for about three hours. Two days later I went to go and start it again and it was dead only turned over three times. I went to go and talk to a Napa parts manager and he said most cars that year had a positive ground cable so i tried that. Once I set it all up i went to start it all i was able to hear was a spark like sound just one so i flipped it back around to negative ground. It did the same thing. This is a 6v car running a 8v battery. One of my distributer cables to the spark plug is really loose possibly a problem???? What is the problem here?

ANSWER: All GM cars, including Chevrolet, run a NEG ground. You cannot use an 8 volt battery without modifications to the voltage regulator and the generator. The current cut out in the regulator is set at about 6.2 volts meaning that the cut out will not open when shutting the engine down after running with the 8 volt battery. This will drain the battery causing it to go dead in short order. Either revert to a 6 volt battery or convert to a full 12 volt system.
Brad

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

QUESTION: Using an 8v battery in a 6v car could that possibly lead up to a starter short.I know the battery is good because the headlights turn on and are really bright just there is no hint of the engine even trying to turn over The car was running and now it will only leave a click sound.

How can i convert it to a 12v or would i have to take it to a specialist  to put in new wiring?

Thanks

Answer
Turning the headlights on to check the battery is not a test of the batteries capacity. The starter uses up to 10 times the electrical power of the headlights. So the battery may be strong enough to light up the headlights but not have enough power to turn the starter. As I said in my previous answer running an 8 volt battery without modifications is a bad idea. The wiring does not need to be changed when converting to 12 volts. The generator and regulator will need to be changed as well as all the light bulbs in the car. A resistor will need to be installed in the wiring for the dash gages and the heater motor will need to be changed or have a resistor installed. The ignition system will need to be modified to run on 12 volts and the radio will need a resistor to drop the voltage to 12 volts.
Brad