Farmall H 12V Conversion

grizzly-man

New User
I have never converted a tractor to 12V; however I want to convert my 1941 H to 12V but all I am finding are kits that convert tractors with a distributor. My H has a Magneto can it be converted to 12V?
 
You actually have a very easy tractor to convert. I did my '47 several years ago, All you need to do is switch out the charging system to match the battery and put in new light bulbs.
The question I have is why do you want to convert it? If you need to have it compatible with other equipment, that's one thing. If you are having trouble starting your tractor, you are better off going through the existing electrical system. I had a lot of trouble with mine even after I converted it. It turned out that the old battery cables were badly corroded inside the insulation. Had I started there, I would have kept it 6volt.
 
This will help. Jim
v6097.jpg
 
You do neo convert the mag it makes its own voltage. Dont connect 12v to the mag just a grounding sw and use the one you now have
 
Thanks for the information Ed. The problem I'm having is the starter doesn't turn over very fast. (I've replaced the battery, Cables etc.)I did get cables from a small repair shop that said use these they are for 6v and not the cheap 6V cables you can get at the autozones, o'reilly's etc. I just finished the restoration this past summer and replaced all the electrical, that being said the one thing i did nothing with was the starter. I am planning on replaceing that before i jump in and convert it to 12v. If that doesn't seem to help themn the conversion will happen.

Chris
 
It is best to run your ground cable directly to one of the starter to frame mounting bolts from the battery. On my 6 volt tractors I have 00 size cables built with soldered terminals made at a good auto parts store for a very reasonable cost. Make sure all your electrical connections are cleaned, shinny and bright as well. My 6 volt tractors start as good on 6 volts as the 12 volt tractors. Your starter might need a little refreshing as well, Hal.
 
mvphoto14147.jpg

Best thing I ever did to my H was convert to 12v neg gnd with alternator. Replace bulbs,reversed the amp gauge leads. Used a voltage dropping resistor and kept the same distributor and coil. No more crappy voltage regulator. Plus everything is 12v for jump starts etc.
 
I did a Super H with a Hitachi alternator from late 70's/early 80's Datsun/Nissan. It is smaller size than GM Delco and wires the same. Both are good alternators with built in regulator. I prefer the 3 wire over the 1 wire.
 
This is a pic of a conversion on a 300 using a Hitachi alternator. Same as an H. Easy hook up and the smaller alternator is easier to get proper clearance compared to the Delco.

Mag has no connections to battery power so there's nothing to do.
a177041.jpg
 
As others have mentioned, converting a tractor with a mag is even easier as the ignition portion is untouched since the mag automatically provides the juice for the ignition.

Bob M (or Bob Melville) has posted several wiring diagrams for both mag style and battery supplied ignitions.

Here is my thread for Farmall h conversion along with lots of pics from me (and others).

http://forums.yesterdaystractors.com/viewtopic.php?t=1156222&highlight=volt+conversion
 
(quoted from post at 18:34:44 12/19/14) This is a pic of a conversion on a 300 using a Hitachi alternator. Same as an H. Easy hook up and the smaller alternator is easier to get proper clearance compared to the Delco.

Mag has no connections to battery power so there's nothing to do.
a177041.jpg

Dean Olson, I have a Mitsubishi alternator from an 82 Mazda with internal regulator, wondering if I could use it on an M, question is it has T shaped socket for plug labeled R and L, how does that compare to the is10 for connections to ammeter and warning light?
 

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