The Stovebolt Site Forums The Shop Area The Electrical Bay 6V to 12V Question??????

Do you have to make any changes to the starter when you change the electrical system from 6V to 12V This is for a 1948 GMC

Thanks.

no you don't, it'll hold up fine under normal use

Bill

I didnt, but if you want to put a 12 volt starter in youll need to swap out the flywheel to match.

I just did that conversion on my 52 and left the old 6v starter in place. As long as you dont grind on the starter for an extended period,,it should be ok.
Ive done the same deal on my other trucks and they've been ok also. Youll be surprised at how quick your truck starts now............
Marty

Treyz,

Wasn't your GMC positive ground. I'm guessing you are going with 12 volt negative ground. I really don't know what items this affects, but you might ask around, or at least keep it in mind.

Stuart

For now you will be good running on 12 volt. Just keep in mind if it ever does give trouble your spinning the starter twice as fast as it was designed for. Again, if it ever does give trouble you will want to upgrade your coils to a heavy duty/hi torque coil and a heavy duty 5 roller drive instead of the original style 3 roller. The new heavier coils will really make a starting difference without worrying about them being able to handle the 12 volt, lots more copper in them than originals.
Thanks
Ken
www.classicgenerator.com

my 6v starter (6-12V conv.) lasted about a year b4 it needed to be replaced. went thru two years & (2 starters). i didn't change the ring gear. this on my 51- 235ci

I addition to all that has been said. Twelve volt system to a six volt starter will work, However the twelve volts to a six volt starter is hard on the starter drive and possible ring gear. The twelve volt to six volt slams the starter drive into the ring gear causing more punsihment to the starter drive its self. One should be able to get by quite a while before problems development.

It is possible to take the starter to a good electrical starter & genarator shop and have it converted over to twelve volt. This will slow down & allow the starter drive to engage at a slower speed.

I have done this on a couple of Super C farmall tractors and worked out well.

I dont want to hijack your topic be my question is for a 6 volt positive ground to a 12 negative ground GMc what about the temp gauge its electrical not like the chevy, what can i do if i want to keep it electric

The sending unit is the ground on those gauges. Just swap wires.

And of course, use a voltage reducer.

I've been running my starter on 12 volts for a few years. With the foot stomp, it should not be a problem for the starter drive, since the gears engage before power is applied to the starter. I do have to wait for it to spin down when I let off if the engine didn't start, and it takes a few seconds. I haven't noticed any undue wear on it.

I think it is always best to wait until the motor stops spinning.

This is from the Tech Tips section on the GMC conversion. (Credit to Patrick's catalog)
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.

Do they make any kind of in line converter to drop the voltage from 12v to 6v ?

Treyz,

The starter motor can draw a huge amount of current which would require a resistor or load of a giant size. The drill would be to continue to use the 6 volt starter, which should last for a very long time, or switch to a 12 volt starter.

Because using the original 6 volt starter is such a easy solution, I don't think anyone has ever found a need to develop a voltage drop for the starter.

Stuart