dc magneto

joenetx · Nov 9, 2014

Looking to buy a good magneto for a 1950 dc case.

CountryCase · Nov 9, 2014

several on ebay

Christopher Mikesell · Nov 9, 2014

Before you buy a new one, what exactly is the problem? It might be easy to fix with minimal money and effort. I should note that converting a tractor to 12 volt can make it much harder to start with a magneto, even if there is nothing wrong with the magneto.

joenetx · Nov 9, 2014

I am using a magneto that's been converted to 12v with a 12v coil with an internal resistor. If a 12v system may cause problems with a magneto, I may leave it like it is.

Christopher Mikesell · Nov 9, 2014

??? I don't understand, do you have a magneto or a distributor, or do you have a magneto that has been rigged to work like a distributor? A magneto in good condition does not need an external coil or a resistor. A magneto is a stand-alone ignition "module" which will create spark regardless of battery voltage.
The problem with converting a magneto driven tractor to 12V is that the impulse coupling (a starting aid built into the magneto) does not snap when the starter turns faster than it did when working on 6V. This means that the magneto has a weaker spark when cranking slightly faster, and it does not automatically retard the timing for starting like it was designed to do (the impulse also retards the timing ~25 degrees at low cranking speeds). This is why most people who convert case SC and DC tractors to 12V replace the magneto with a distributor.

joenetx · Nov 9, 2014

It's a case magneto. The internal coil is burned up. A hole was drilled in the cap to hook up the coil spark wire.

Christopher Mikesell · Nov 9, 2014

Cost-wise, your cheapest option will be to get a distributor drive off of a salvage tractor such as an Allis or Farmall ($35-$75). Both magnetos and distributor drive units were made to fit the same SAE standard flange. Then you can convert to 12V without the faster starter-speed problems. Additionally, there is a distributor which will give the correct 25 deg. of timing advance, although someone would need to look in the archives to see the correct model number for this distributor. Getting ahold of the right distributor will probably take more time and money. Also, used parts are rarely like-new.
If you want a magneto, then your cheapest option is to replace it with one off of a salvage tractor ($35-$75 but risky), an old one that is still "hot" ($75-$125 but still risky in to long term), and a new/freshly rebuilt one/have yours rebuilt ($125-$400). It would be best to stick with 6V if this is your desire.

joenetx · Nov 10, 2014

Thanks for the input. it is rigged to work like a distributor 12v to the points.

Paul f · Nov 10, 2014

Right angle Delco distributor model 1111411 works great as a replacement if you want to get away from a mag. It will work 6v or 12v just have to get the right coil.

joenetx · Nov 11, 2014

If I get a distributor, how would I time it on a 1950 dc?

Christopher Mikesell · Nov 11, 2014

You would set the static spark on cylinder #1 so that it sparks when the 3/16" hole is centered in the hole.

joenetx · Nov 11, 2014

Are you referring to the hole in the flywheel cover for finding tdc?

dc magneto

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