Im in a little trouble and could use some help. Im converting a Farmall H 1939? to 12v. I bought a kit. It has No instructions. everything is wired. BUT I cant get voltage to the coil. by the way the coil is not the black round type type with the coil spark wire coming out the top. it is built into the distributor with one wire screwed in the side. Where can i find a reliable wiring diagram to follow to make sure its correct? also, when I wired the resistor in series with the wire to the coil, it just got overheated? I have no idea why. Can any body help? PLEASE!
12V conversion Farmall H
- Thread starter FredFWP
- Start date
- Views: 5221
Roadworthy
Elite Member
You're not giving much to go on. If the coil is built into the distributor and you can't get voltage to the coil that implies you may not have voltage to the distributor either. Generally the only time you have voltage to the coil is when the points are open. When they close they short the coil to ground which induces a spark. Since the old coils actually ran at six volts the resistor is intended to drop six volts leaving six for the coil. It may help to think of it as two separate circuits. The points and coil primary are one circuit in conjunction with the ballast resistor and ignition switch. When power is on opening and closing the points makes spark in the coil secondary. The distributor and rotor move this spark around to the proper cylinder at the correct time. Check your primary wiring.
Thanks for responding. Im new to farmalls. I have two Ford 8n's that I have converted to 12v. I now realize that this tractor has an H4 magnito. As I understand it, the wire on the side goes directly to a kill switch on the dash column. (The switch is of one wire design and just pulls out and pushes in. Im sure you're familiar.) It grounds the points as I understand it, shutting off the tractor.. I originally thought it was the power lead to the magnito coil. I assumed that if I put the resister in series with that wire and placed the other end on the ignition switch, when the ignition switch is energized, power would go to the magnito coil and provide spark. It did not. All it did was burn up the resistor. There are no other osts on the magnito, so I'm scratching my head trying to figure out how the magnito gets its power, and where I'm to wire the hot lead to the magnito. Can you help?
Industrial Toys
Super Star Member
- Joined
- Feb 25, 2008
- Messages
- 16,742
- Location
- Ontario Canada
- Tractor
- Kubota R510 Wheel Loader + Cab and backhoe, JD 6200 Open Station, Cushman 6150, 4x4, ten foot 56 hp Kubota diesel hydraulic wing mower, Steiner 430 Diesel Max, Kawasaki Diesel Mule, JD 4x2 Electric Gator
There is a ton of information on this. Google it. A cursory examination however shows mostly conventional coils.
Thanks everybody. My lack of understanding of the difference between a magnito ignition (which I now know generates its own voltage by the turning of the engine) and a coil/ distributor ignition (which needs voltage from a battery or alternator/ generator) led me astray. The kit i purchased came with an extra wire and a resistor which, in my application are not used. Since I didn't know that, I was trying to figure out what they were for and where they went on the magnito. Now that I know, my conversion became much easier. I was already done and didn't realize it. Thanks!