6v to 12v conversion

judge the dog · May 23, 2018

I have a 1946 case sc. Its all original. It has no spark. Turns over but no spark. I suspect the mag is shot. What do i need to convert it to 12v? I am looking for a list of parts. A rebuilt mag is 500. A conversion is cheaper. Thanks

bcp · May 23, 2018

Rebuild it yourself? Kit and other stuff here:

Case SC Parts - Electrical System Parts

Bruce

judge the dog · May 23, 2018

I think i would honestly rather convert it

Harry in Ky · May 23, 2018

Convert what? The mag is self contained. Makes no difference if the tractor's electrics are 6 volt or 12. If you want 12 volts for faster cranking, that's one thing. You still need to deal with the mag as a separate issue. Probably just needs attention to the points. Cleaning/filing and adjusting the originals is probably a better bet than replacement with what's available on today's market.

rScotty · May 23, 2018

Harry in Ky said:
Convert what? The mag is self contained. Makes no difference if the tractor's electrics are 6 volt or 12. If you want 12 volts for faster cranking, that's one thing. You still need to deal with the mag as a separate issue. Probably just needs attention to the points. Cleaning/filing and adjusting the originals is probably a better bet than replacement with what's available on today's market.

I agree. Old mags are great. The mag is completely separate from either 6 volt or 12 volt. Mags are designed to work all by themselves because they rotate when you crank the engine; they have no connection to the electrics in any way, just to the spark plug and a grounding wire running from the points cover used for turning the tractor off.
That simplicity & independence from the electrics is why a lot of light airplanes use mags.
First thing like Harry says is to check the points. I bet you can fix it in ten minutes. The most common thing that stops a mag from working is that the cam follower that opens the points wears down and the points don't open anymore. Take the obvious end off the mag and have a look. This is either very easy or you are looking in the wrong place. Look inside. The points have a little plastic arm that rides on a cam & should open them to about .010" at the high point. Remember, a mag only sparks when it rotates. So set it to compensate for about .012" of the wear that has happened and crank the sc. You should see a spark at the points and at the plug.
If not, ask around the local antique people to see who does mags.
rScotty