1939 D Magneto Options

[B Duncan]

I have a D with an Edison Spitdorf mag. It has been rebuilt a number of years ago, but is currently firing on one cylinder. I have found that parts seem to be more expensive than the Wico type. Would a Wico X be a good replacement, or should I repair the one that I currently have. If my memory serves me correctly, doesn't the Wico X fire on every impulse? This tractor is hand start, so anything that makes it easier to start would be nice.

Thanks

 

[John T]

Yes, the Wico X fires each 180 on every impulse. It's a more readily available mag with better parts availability, although it doesn't have such a classy look, if that or the correct police make any difference and depending on what mag your tractor used originally, the Edison may or may not be your personal choice. While all mags fire when they impulse, on the 2 cylinder Deeres its a matter of mag speed whether crank or cam speed that has to do with timing and if they also fire on the exhaust stroke TDC. I like the looks of the Edison especially on a D, but the Wico and its parts are easier to come across.

John T

 

[Kent Petersen]

B Duncan i have used rebuilt Wicos and new ones on hand call me at 605 270 1844 if you are interested

 

[Mike M]

If you could luck out and find a newer Fairbanks Morse that was made to fit your tractor then you would have a really good mag.! They really throw a hotter spark than the Wico's.
Probably hard to find one. So a Wico X would be the next best.

 

[buckeye al]

You mention it fires on only one..... Makes me wonder... Was the mag off of the tractor recently? Like maybe before this problem started?

Isn't that ES mag like the FM DRVB series where there are no lost sparks? If it's firing on one but not the other is it MAYBE just installed a half turn out of time with the engine or maybe has a distributor stage, plug wire or plug problem?

The same "stuff" inside the mag makes the sparks for both cylinders and if one works but not the other, is it really so bad a mag as to need scrapped? I'm not saying it isn't bad but yet I wonder, is it really that bad?

 

[John T]

Yep, the Wico C and X were direct drive (same RPM as crank) and fired at BOTH Power and Exhaust TDC, while some other mags used a 1/2 reduction gear drive and they only fired on the Power TDC IE no lost spark at exhaust TDC. If a Wico is 180 out of time a simple top and bottom wire swap can make them run but that's NOT true on those 1/2 speed reduction gear mags.

John T

 

[B Duncan]

Thanks guys! Kent, I just might give you a call, if I can't find the parts reasonable to fix mine.
Thanks again!