magneto to coil conversion

thank you to everyone who responed to my request. El Toro, I have a 1939 F-14 FARMALL The magneto on this tractor is different from the picture you sent to me. Mine has the big (u) shaped maginet around it, and the 4 plug wires coming out of the end cap. I need to know where and how to connect the hot wire that comes out of the coil to the magneto.
thank you,
John

Do have a picture of that mag and cap? Hal

You may not be able to make the conversion on that mag. You can have that mag rebuilt or you can buy one from thefordsonhouse in MI. Call them at 906-786-5120. Hal

(quoted from post at 11:36:07 01/16/09) thank you to everyone who responed to my request. El Toro, I have a 1939 F-14 FARMALL The magneto on this tractor is different from the picture you sent to me. Mine has the big (u) shaped maginet around it, and the 4 plug wires coming out of the end cap. I need to know where and how to connect the hot wire that comes out of the coil to the magneto.
thank you,
John

Click to expand...

If it is an E4a (picture at link), then it has rotating coil, points, and a slip ring to couple the HV out, thus making a conversion to battery powered coil quite difficult or perhaps impossible.
http://ytforums.ytmag.com/viewtopic.php?t=397415&postdays=0&postorder=asc&start=0

If you are willing to remanufacture the Mag cap, you might be able to drill a hole into the cap to allow the high tension wire from the coil into the center to get to the rotor. Haven't seen it on that mag, but If I was set on doing it I would try it. Another possible solution is to use a 4 cylinder distributor from any of various cars or tractors (IH included) that turn in the right direction. Make a drive adapter to fit the engine, and a wooden or metal support to position it in alignment on the existing Mag mount. JimN

Jim, that E4A would probably be a bear to convert, not only due to HV path that you address, but since the primary & secondary coils rotate & it appears to me that both sides of the points are isolated from ground and rotate, it isn't going to be easy to connect to the points!
In looking into this (I have one on the bench), I noticed something else interesting that I thought I might get you to comment on. Every other spark is of opposite polarity from the previous spark.
Every few months, it seems that there is a controversy about the advantage/disadvantage of a positive vs negative spark polarity & often compounded by some who mistakenly think spark polarity is tied to POS/NEG battery ground.
Well, with the E4A mag you have both! I have never put much in the +/- argument, beyond better electron emission from a hotter electrode & that would occur not at start up when you need it most, but after a run period.
Apparently IH didn't either since theE4A alternates, every other firing.

The shaft has insulators on the bearings to isolate it from the case, which brings up another question for you.........did this mag installation utilize an insulated coupler to the mating shaft? If not, it would seem that isolation would be lost..........it must have used a phenolic insulated coupler.??