Ford 851 12volt conversion

kene69

New User
I puzzled and was hoping someone might fill me in with some info. I Ordered the 12 volt conversion kit to put on this tractor. The tractor has a 6volt positive ground. So do i need to haul around two battery's. One for starting and one for running? If you replace the generator with an alternator wouldn't that only put out 12 volts plus for running the tractor? What am i missing here?
 
What you are doing is "converting" the electrical system to 12 volts.

You will replace the 6v battery with a 12v battery, AND change the system from positive ground to NEGATIVE ground. Very important step!

Mount the alternator, which will require fabricating a bracket (unless the kit came with a bracket), carefully align the pulley and match the pulley to the belt width.

Wire the alternator per the instructions.

Reverse the polarity of the amp meter connections.

Reverse the polarity of the coil connections. The + terminal will wire to the ignition switch, the - terminal will go to the distributor. Also, either replace the 6v coil with a 3 ohm 12v coil, or add a resistor to the existing coil.

Change out all 6v accessories to 12v.

The starter will not need to be changed at this time. It will work on 12v, just be careful not to crank on it for too long as it will heat quickly. If it ever does fail, that would be a good time to change it over to 12v.
 
Depending on the type of tractor and alternator, you maybe able to flip the mounting bracket to mount the new alternator.
 
your explanation and description of the change is the clearest and simplest I've ever seen.
 
Steve,
I purchased a Jubilee that was converted to 12v. Every two years in the winter, I would shear off the starter drive. In the bell housing there pieces to 10 other starter drives. The second time it happened, it took off part of a tooth on the starter ring on flywheel.

I purchased a 12v starter from YT and never been happier.

I couldn't purchase a 12v starter for my Farmall C. After loosing two starter drives, I replaced the 12v battery with an old lawn mower battery, at the time battery only measured 180 cca. It works great, starts in the winter. Farmall has a mag so battery voltage isn't important in making the spark.

The person who converted my jubilee, had no clue how to wire it because you no longer need the 6v voltage regulator. It was easier for me to just start over and rewire it using new wires. Not that complicated.
 

Thankyou very much, i appreciate your clarity on the subject. I purchased the 12 volt converter kit from YT but it does not come with the coil or electronic ignition. I bought the electronic ignition also and a 6 volt positive ground coil. so i guess i will return the later two items and order a 12 volt coil and ignition.

Does this sound correct?
 

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