Ignition help 1958 641 workmaster

Looking for some help and advice. I did a 12-volt conversion with the ballast resistor on my 641. I think I want to convert to electronic ignition. Do I buy a 12-volt neg kit, a 6-volt neg kit or 6-volt pos kit? I still have the 6-volt coil. At this point should I just go with 12-volt coil and 12 volt EI kit? Thanks for advice in advance!

(quoted from post at 16:33:08 07/11/21) Looking for some help and advice. I did a 12-volt conversion with the ballast resistor on my 641. I think I want to convert to electronic ignition. Do I buy a 12-volt neg kit, a 6-volt neg kit or 6-volt pos kit? I still have the 6-volt coil. At this point should I just go with 12-volt coil and 12 volt EI kit? Thanks for advice in advance!

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2v with whatever +/- ground you have & 12v coil and ash can the ballast. KISS

(quoted from post at 16:33:08 07/11/21) Looking for some help and advice. I did a 12-volt conversion with the ballast resistor on my 641. I think I want to convert to electronic ignition. Do I buy a 12-volt neg kit, a 6-volt neg kit or 6-volt pos kit? I still have the 6-volt coil. At this point should I just go with 12-volt coil and 12 volt EI kit? Thanks for advice in advance!

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Mike, as JMOR told you 12 volt - yes. 6 volts and EI don't always work together great. Too easy to end up not having enough voltage to fire the 6 volt module.

You say you've already done the 12 volt conversion. Odds are then you got a 12 volt alternator. If so, odds are that's negative ground, and you can't change the battery polarity without damaging the regulator in the alternator. If all that's the case, go with 12v neg ground module. And again, as JMOR said, ditch the resistor(s) and install a 12 volt coil that does not require a resistor. Those coils have somewhere around 2.5 -- 4.0 ohms of primary resistance, thus no resistors needed.

...I think I want to convert to electronic ignition.... Why? There's nothing wrong with EI but don't do it because you can't figure out what you did wrong with your 12V switch over job. That is a rookie (and some oldies) mistake like going from 6V to 12V. First, the Ballast Resistor was only used from '39 thru '49 with the front mount distributor. Forget model year, means nothing; all gas units were the same wiring config from '53 thru '62. So let's back up a few steps and tell us more. A 12V conversion should have, a 12V GRP 35 battery; 12V (DELCO 1-Wire is best) Alternator; the GEN and the VR get removed from the circuit altogether. Repave 6V coil with a 12V coil. What did you do? Once wiring is corrected, be sure the ALT (or GEN if 6V) have a belt tensioning device attached. No belt tension and you get no batter charging. 6V, 12V, 24V, 32V, or EIA, it's your tractor and your $$$ so you can do whatever you want but be sure you know what you are doing or ask for help. FACT: 99.98% of all non-running/non-starting/poorly running tractor issues are due to mucked up wiring whether 6V or 12V.


FORD NAA/600/800/900 12V CONVERSION:

FORD NAA/600/800/900 OEM 6V WIRING:


Tim Daley(MI)

Thanks, that is exactly what I had in mind. I seem to go through a lot of points.

Mr. PloughNman, thank for the diagrams and reply. BTW my 12-volt conversion went great. The kit from YT was spot on. 12-volt single wire alternator, wiring, brackets, and ballast. Run better than it has in 20-years. Hadn't run at all in 5-years, I parked it and bought a brand new orange tractor. Moved up 50-years in technology. My problem has always been inconsistent and weak spark. Solution is always new points. Cleaning, adjusting, replacing points every 50-hours for 30-years. I have a little blowing money and think I'll do the EI conversion. I don't need or really use this tractor anymore but I am having fun playing on it again.