Would like to convert my 47 Chrysler Windsor over from positive ground to negative ground. From what I've been reading, it doesn't take too much. Reverse the ammeter gauge wires, reverse the wires on the ignition coil, polarize the generator and reverse the battery cables. There is no modern accessories in the car now. Changing would allow me to have a radio, even if it is with a 12 to 6 volt converter. (Keeping the car 6 volts) I just wanted to run it by the more experienced people on here to see if I'm overlooking anything. Thanks Wayne
the coil - you do NOT reverse the wires. + is still + and - is still -. You leave the - side alone, it should only be going to the dist/points. The + side you need to change from going to the chassis to going to the IGN term on the ignition switch.
Quote: Originally Posted by Mike51Merc Change all the light bulbs. He was probably thinking that he was switching over to 12v.
No, light bulbs won't matter. You'll have to rewire the solenoid and the motor part of your starter though, they will run in reverse otherwise. Thr radio won't work backwards, might even damage something or catch on fire. Like you mentioned, ammeter will be out of wack. That's all i can think of off the top of my head. Relays might need to be rewired too.
The starter doesn't mind the change in polarity. Coil has to be neg side to dist (points) and pos side to ignition switch.
Starters don't care about wrong grounds. Neither do relays and solenoids. Electrical gauges might not work, though. If all you want is a 12v radio, well, most radios have a ground wire and a power wire, just hook the ground to power and the power wire to the ground, coming off whatever you have for a 12v converter, and keep it positive ground. I should say, newer starters with permanent magnet fields will turn backwards with the wrong polarity. Not a problem on the older cars.
I can't imagine the starter working with a swap of current. If it runs backwards or actually it won't run at all, as the solenoid will suck 'in' instead of out. I will say i told ya so so hard.
You are wrong, so so hard. A non permanent magnet starter will only spin the direction it's built to spin. Regardless of polarity.
To reverse a starter motor you would have to reverse the current going through the field windings; since you are reversing both the field and the armature current (so to speak) it should run in the same direction. Being positive ground or negative ground will make no difference. I totally agree with badshifter.
I did this switch on my old 51 Lincoln without altering the starter. The first time I hit the button, it turned over VERY slowly and odd sounding ( I'm guessing backwards, despite what others are saying ) and stopped working with a puff of smoke and the stench of burned electronics. Prior to switching to a neg ground it had worked flawlessly. Take that for what it is worth.
I think the direction a starter turns is determined by the position of the brushes. When I was racing karts we used old Ford starters to get them going, we just rotated the brush plate until it ran in the reverse direction, re-drilled the plate and bolted it back together.
The starter on my 48 Studebaker ran fine even when I changed polarity anr ran 12 volts. The 6 volt coil burned out real quick when I left the key on, though.
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