b414 pos to neg gnd conversion

   / b414 pos to neg gnd conversion #1  

bfktwb4

New member
Joined
Apr 6, 2014
Messages
3
Location
Post Oak, Virginia
Tractor
Ford 930
Folks, I recently acquired a IH 414. I would like to convert it from positive ground to negative ground system. A one wire alternator is envisioned to get rid of the generator and voltage regulator. I'm pretty sure how to do that. Also an ignition switch with a glow plug activation (accessory position) and with a start/run position (rather than a starter button). I am confused on the glow plug wiring and voltage needed for the glow plugs. Do I disconnect the current ground strap on the glow plug at the front of the engine and just wire the plugs to the 12 v accessory position on the ignition switch or do i need a resistor in series to change the 12v to something else to the glow plugs. If so what OHM and wattage resistor?
 
   / b414 pos to neg gnd conversion #2  
You may be in over your head on this one. The conversion my not go smoothly. Your starter is a DC motor. Will swapping polarities make it turn backward? If so that would not engage the Bendix or crank the engine. Your idea of a start position on a normal ignition switch could work though it should go through some sort of solenoid and not directly to the starter. Putting the glow plugs on the accessory position won't turn out well. They will also be on the whole time the ignition switch is on. It would be better to activate them through a button or switch on the dash - perhaps your old starter button? The glow plugs do not care if they are positive or negative ground, they are just heating elements. If I were you I'd leave the tractor positive ground and perhaps try to locate a positive ground alternator. There may be companies specializing in restoration of old tractors who could provide what you need. Years ago many vehicles were positive ground. In the fifties they went to negative ground in this country. Why? I don't know. The English continued to produce some positive ground stuff into the seventies.
 
   / b414 pos to neg gnd conversion
  • Thread Starter
#3  
You may be in over your head on this one. The conversion my not go smoothly. Your starter is a DC motor. Will swapping polarities make it turn backward? If so that would not engage the Bendix or crank the engine. Your idea of a start position on a normal ignition switch could work though it should go through some sort of solenoid and not directly to the starter. Putting the glow plugs on the accessory position won't turn out well. They will also be on the whole time the ignition switch is on. It would be better to activate them through a button or switch on the dash - perhaps your old starter button? The glow plugs do not care if they are positive or negative ground, they are just heating elements. If I were you I'd leave the tractor positive ground and perhaps try to locate a positive ground alternator. There may be companies specializing in restoration of old tractors who could provide what you need. Years ago many vehicles were positive ground. In the fifties they went to negative ground in this country. Why? I don't know. The English continued to produce some positive ground stuff into the seventies.

Thanks for your thoughts, particularly the one about the ACC position for the glow plugs being on constantly. My ford 1910 has such a switch on it and now that you mention it it may have a disconnect from the left position as a car ignition (acc) switch does not. I plan on a solenoid for the starter, polarity doesn't matter on the starter. Once again thanks.
 
   / b414 pos to neg gnd conversion #4  
One further thought - a tractor ignition switch is more expensive than a standard automotive ignition switch - like to the tune of $80 versus $10. An actual tractor ignition switch has a position to the left where the car ACC position would be. The difference is that the tractor switch is spring loaded to return to off. The single counter clockwise movement is intended to activate the glow plugs and is not connected when the key switch is in the "run" position. Some switches may activate the glow plugs while in the "start" position but definitely not in "run". When my Mitsubishi switch burned out from a prior owner circumventing a current limiting resistor I just replaced it with a standard ignition switch and added a switch for the glow plugs. It was a lot cheaper.
 
 
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