Wait! I have a positive-ground GMC, what do I
This so easy, you'll kick yourself for not having
figured it out on your own. All you have to do to convert that Jimmy to
negative ground is:
- Disconnect the battery (VERY important first step)
- Reverse the wires on the coil
- Reverse the wires on the ammeter
- Reverse the battery cables. While you're at it, why not switch the
ground cable from going to the frame to a starter mounting bolt or
the transmission? It's better than the frame.
- Put all your tools away and sweep the garage floor, because you
are DONE. Oh, yeah. Power up the system to see if you did it right.
Easy job. By the way, this method works for Fords,
too (should you have one laying around).
12 volts, but looks all original
Okay, this one is a little harder, but still pretty
easy. Even a Marine can do it. This method assumes you have either the
original wiring harness, or you have replaced the original harness with
a new 6-volt harness. Is your 6-volt harness adequate to convert to 12
volts? Yes, because the 6-volt system produces twice the amperage of the
12-volt system. So, the 6-volt harness is actually heavier than needed
for the 12-volt conversion. With that out of the way:
- Disconnect and remove the 6-volt battery. If you discard it, make
sure you do so properly. Used Lead acid batteries are hazardous
waste, so please dispose of them properly -- it's the law.
- Remove your 6-volt generator.
- Replace with a 12-volt generator. I got mine from a guy hotrodding
a '57. It fit perfectly and looks almost identical to the original
- Remove the 6-volt voltage regulator and replace it with a 12-volt
one. Again, you can probably use the one that came with the 12-volt
generator you found.
- OR, if you want to be anal and maintain strict originality, you
can use your 6-volt generator -- just take it to a good electrical
shop and have them replace the 6-volt field coils with 12-volt ones.
Just don't forget to replace your voltage regulator...
- Replace your 6-volt bulbs (headlights, taillights, parking lights,
dash lights, dome lights, etc) with 12-volt bulbs.
- Put a ballast resistor* in the line between the ignition switch
and the coil
- Put a voltage reducer* in the power line to each 6-volt accessory
switch (radio, heater, etc)
- Put a Standard Ignition* in the line to the gas gauge.
- Install a 12-volt coil
- Install a 12-volt battery that fits your battery tray (duh).
- Power up the system and check it out.
12 volts, but with an alternator
This one isn't quite so easy. I tried this the first
time around and it took a few tries to get it right. At any rate, this
approach is pretty widely used and has a lot of advantages, but you lose
originality -- you have a big, ugly alternator sticking out like a sore
thumb. Yuck. If you can live with that, here's what you do:
One low-buck way to install an alternator on a stovebolt
six is to use All-Thread, six nuts, & six lockwashers. Using the
original generator bracket, cut the All-Thread to size so that the
length is a little longer than the bracket. Use a nut and washer on
either side of outer bracket; a nut and washer on each side of the
alternator; and a nut and washer on each side of the inner bracket.
Using All-Thread also allows you to adjust the alternator to line up
with the harmonic balancer and the water pump pulleys. It also acts like
a shaft on which the alternator can rotate to be adjusted to tension the
fan belt. Make sure that the All-Thread, nuts, and washers are the same
size as the alternator and generator bracket holes. If you would like a
ready made alternator adapter one can be ordered from the fine folks at Buffalo Enterprises.
This article was used with the permission of "The
Stovebolt Page". Thanks John!