Converting 6 volt to 12 volt 1956 JD C40

donbow11 · Post by **donbow11** » Wed Feb 17, 2016 12:49 pm

Could someone please tell me what alternator will work well with this type of conversion and how should I wire it. I have installed an alternator from a 1976 Chevy pickup, I upgraded the coil and replaced the new battery to 12 volt. I don’t think it was wire correctly and may have fried the alternator. Any help will be most appreciated. Thanks

Stan Disbrow · Post by **Stan Disbrow** » Wed Feb 17, 2016 1:16 pm

Hi,

Most use a 1-wire alternator. Meaning the regulator and cut-out is internal. So, all you need do is hook one wire from the alt to the batt. Like the little Denso units used on so many cars these days.

Stan

B Town · Post by **B Town** » Wed Feb 17, 2016 1:20 pm

Remember to protect the points! 9.6 volts not 12+ volts, Bruce

Stan Disbrow · Post by **Stan Disbrow** » Wed Feb 17, 2016 2:46 pm

Hi,

The upgraded coil takes care of the points.

Stan

donbow11 · Post by **donbow11** » Wed Feb 17, 2016 9:06 pm

Thanks Stan I’ll look for the single wire alternator and Ill upgrade the coil. Thanks again, Don

Stan Disbrow · Post by **Stan Disbrow** » Thu Feb 18, 2016 5:25 am

Hi,

On the coil, you can get a 12v one, or add a resistor to the 6v one.

I am in the same boat now. My starter armature fried. So, I took it to a local shop, and they rebuilt it as a 12v. I don't feel like doing a full conversion, so I have a 12v battery on the starter and a 6v motorcycle battery on the rest. For now, anyway. When it warms up I will be more inclined to switch the rest over. Maybe.

Stan

B Town · Post by **B Town** » Thu Feb 18, 2016 6:59 am

Stan, you are correct regarding the up graded coil, as long as it is the internalresistance variety. Lots of the younger parts people will hand you a coil, thinking a coil is a coil. Take care, Bruce

Stan Disbrow · Post by **Stan Disbrow** » Thu Feb 18, 2016 7:42 am

Hi,

So true. Although these days most off the shelf coils are 12v and it more likely you would get the wrong one if you went looking for a 6v one.

This is why I have the wrong armature in my rebuilt starter. But it is a good time for me to make the change anyway. It is just I wanted it runnable in case of snow (I have seen a foot here in NC a few times) but didn't really want to do all of the necessary work in the cold. So, a temporary two battery solution.

Stan

Paul J · Post by **Paul J** » Thu Feb 18, 2016 11:16 pm

I didn't see any mention of switching to negative ground, but I might have missed it.

The O.P. said, "I don’t think it was wire correctly and may have fried the alternator."

Positive ground is tough on most alternators. I'll bet he has it at negative ground, but just saying in case he doesn't.

Lu47Dan · Post by **Lu47Dan** » Thu Feb 25, 2016 1:32 pm

If you have the ability to rebuilt your present alternator, Jegs sells a rebuild kit for the 10SI alternator.
http://www.jegs.com/p/JEGS-Performance- ... 4/10002/-1
I have done quite a few of them with this kit over the years.
Dan.

Zachary Hoyt · Post by **Zachary Hoyt** » Thu Feb 25, 2016 2:18 pm

I get 10SI rebuild kits off eBay. There are a whole range of kits depending on how many parts you need to replace. The one I usually buy is around $15 and has the parts I generally need.
Zach

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Converting 6 volt to 12 volt 1956 JD C40

Converting 6 volt to 12 volt 1956 JD C40

JD 1956 C40 6 to 12 volt conversion

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