Advice needed. Starter rewind from 6 volt to 12 volt

[bmorgil]

I accidentally posted this in the wrong place. I am not sure how to delete it from the tech library.

Hello all, I need a little advice. I am converting my CJ-3A to 12 volts. I have read that many Willys owners just pump in 12 volts to the 6 volt starter. I have a small background in old school electrical technology. I do know that this will create high starter current and, high stater torque. Both do not seem desirable to me. Has anyone gotten their starter motor armature rewound to 12 volts? Does anyone know of a reliable source?

Bob

[Sebastian21]

I have been using a 6 volt starter on a 12 vote system for several years. The only thing is it heats up if you crank it for a long time and this heat up causes it to slow down. I just let it cool for a minute or two. I can not tell a 6 volt starter by looking at it.

[bmorgil]

Thanks for the first hand experience! This is the same advice LarrBeard gave me. I am going to give it a try. I have heard this can cause the ring gear on the flywheel and pinion gear on the starter to wear. I take it you have not seen this issue. This rumor may have been started by persons guessing what would happen. I am going to go for it. It sure does seem like the easy way. I would hate to have to pull the flywheel if it did eat the gears however.

[Sebastian21]

I am trying to think why the fly wheel would wear out faster. If the starter is alined correct and engage the flywheel why it would wear. Has anybody else heard of a 6 volt starter on 12 volts wearing out a flywheel?

[LarrBeard]

I am trying to think why the fly wheel would wear out faster. If the starter is alined correct and engage the flywheel why it would wear. Has anybody else heard of a 6 volt starter on 12 volts wearing out a flywheel?

Remember, with Jeeps, anything can and has probably happened. But, having said that - the ".. running a 6-volt starter on 12-volts wears out the ring gear/flywheel..." story is probably somewhere up there with fake news, sea stories and urban myths.

I'd worry more that Sasquatch is going to come out of the woods and eat your lunch.....

A fairy tale starts out; "Once upon a time ..."

A Sea Story starts out; "There was this one time when I was in ...."

After that, they are about the same.

Happy New Year guys!

[Sebastian21]

I think that puts that idea to rest.

[bmorgil]

When you double the voltage to the starter, the torque/HP of the starter will increase. I think we agree on that.This appears by the experience of you guy's, to spin the motor faster at start up. So we definitely have more power at the starter. This certainly increases the load on the gear teeth. What you all have proven out through experience is, it doesn't matter. It is still within the capability of the design. The gears are strong enough to endure a little extra torque. I am definitely going to try it. I am willing to bet when Jeeps went 12 volts from the factory, there was little change if any to the design of the gears. This looks like an easy way to get a high torque starter!

[Haymaker]

I am certainly not a mechanic, but I did have an experience with a farm tractor converting it to 12 volts. Yes the starter had more torque , and spun the engine faster, but when you went to start it would slam into engagement much harder than with 6 volts. So after a few years I started having problems. If I still had the same tractor I wouldn't change it, after all a good 6 volt battery would start it OK even when it was cold. I just thought that 12 volts would be better, but 6 volt systems worked for fine for many years.

[LarrBeard]

We're covering this subject pretty thoroughly, but folks are curious.

The CJ3A, Jeepsters, trucks and wagons (46 - 501/2 or 51) used a push-in starter that creates a lot less shock to the ring gear that the spin-in Bendix arrangement. On those starters, you push a button or pedal, the drive gear engages, then a switch applies voltage to the starting motor. The armature doesn't get a head start on spinning up before it engages.

Carl Walck has a good explanation of that particular starter here:

https://www.youtube.com/watch?v=yywTjyLRoQs

[bmorgil]

Mine has the foot pedal on the floor. No solenoid to drive the pinion in, just your foot. I don't see this causing any problem as you said LarrBeard. This should work great.