The Stovebolt Site Forums The Shop Area The Electrical Bay 12v system 6 volt starter

reading thru all these posts i came across conversations about 12 volt systems using 6 volt starters and 12 volt starters using 6 volt flywheels. So i have a 1940 1/2 ton chevy pick up that has been converted to 12 volts (216 engine) . i dont belive the flywheel wheel was ever changed i think it was original to the truck or engine it was purchased with. Which was a 6 volt system at time of purchase. i later changed the system to 12 volt and used the same 6 volt starter for a while. After a while i started having some starting trouble and took my starter to be checked . it was repaired or replaced to a 12 volt starter after i told the service tech that my truck was 12 volt . COULD THIS HAVE CAUSED A ISSUE IF I NEVER CHANGED THE FLYWHEEL ? should i jus go back to a 6volt starter ? would using a 12volt starter to 6volt flywheel cause any timing issues or engine running issues. And is it even possible to run a 6volt starter on a 12volt battery?

When I restored my 51, I kept/rebuilt the original 216, with the 139 tooth 6 volt flywheel. I converted everything (including the generator) to 12 volt....except the starter, kept it 6 volt. And it will spin the motor over in the extreme. You just don't want to crank it and crank it for extended periods. If everything is in time and all fuel and spark are good, then you shouldn't have to crank it for extended periods, and a 6 volt starter will last a long time, on a 12 volt system. I had a local auto electric shop convert my generator to 12 volts, and they rebuilt my 6 volt starter.

You say you started having starting trouble, as in ? We know your flywheel is correct, and the starter was/is correct, cause you say you have used it for a while. Was your 6 volt starter 'repaired', or did they sell you a new 12 volt starter? Cause if they sold you a 12 volt starter, then yep, you're gonna have issues. The bendix on a 12 volt starter is not gonna match a 6 volt system flywheel. Going to be some grinding and gnashing of teeth, so to speak.

I personally like my 6 volt starter on my 12 volt system. Works extremely well.

Thanks for the input . I cant remember why i originally took my starter in for repair i believe i was isolating a starting problem i was having. So when i mentioned to the starter shop that i was running a 12 volt system he advised that i put a 12volt starter so i went ahead with his advise. I never knew there was a 6 volt flywheel and a 12 volt flywheel or else i would of kept it 6 volt . I believe they converted my 6volt starter to a 12 volt . But i know for sure i have a 12 volt starter now. So i guess im going to go back to a 6 volt starter to stop any further damage to my flywheel . Thanks again

If the shop converted the 6 volt starter to 12 volt, provided it was done correctly, they just changed the electrical components to 12 volt. The starter drive should still be the 6 volt version therefore your 6 volt flywheel will be just fine.🛠

Martin is correct (as he most always is). If all they did was convert YOUR 6 volt starter, them all is well. If they sold you another starter, and it being a 12 volt, then there's the issue. You need to know if what they gave you was actually your old starter.....or another starter.

Side by side, laying on the workbench, a 6 volt will look exactly like a 12 volt starter. The bendix (the starter drive) is different on the 12 volt. (I think the bendix shaft and tooth count on a 12 volt is larger....I may need correction on that). But the later model trucks, that came with and are using a 12 volt factory design, have a larger flywheel (which makes it a larger tooth count flywheel).

GOT IT. makes perfect sense.. you guys are great help . Thanks again

It's impossible to put a 12 volt armature in a 6 volt housing- - - -the shafts are different size. A 6V starter could be partially converted by using 12V field coils, but the 6V armature and drive gear would still need to be used. The 6V armature shaft and drive gear are 5/8" diameter- - - -12V items are 1/2" diameter. The gear tooth angles and thickness are also different between 6 and 12 volts, and the drive lugs don't match up. 6V drive lugs for the gear are straight, and 12V drive lugs are angled so the gear turns slightly as it engages.
Jerry

I'm surprised you'd say that Jerry. For someone with your mechanical skills, I'd say that nothing is impossible.

I've not pulled a starter (either 6V or 12V) apart, but would it be possible to use the end plates from the 12V along with the armature? Just asking out of ignorance.

But the whole 6V to 12V starter conversion may not be worth the effort, what with the drive end differences as well.

Maybe "impractical" would be a better choice of words, since the drive gear and flywheel would also need to be swapped, and at that point you've got a full 12V system anyway.
Jerry

The case of the 12 volt starter is tapered to a smaller diameter on the forward end. Is the starter that you got back from the guy like that?