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I need to change polarity from positve to negitive ground

15K views 10 replies 5 participants last post by  Frisco 
#1 ·
Does anyone know how to do this ? Would it be hard to convert the starter motor and generator to negitive ground. Would it even be necessary to do all that ? Can`t find any info about in the repair manuels, so here I am,looking for some help... > KEEP SMILING < ... Dan
 
#4 ·
Be sure to switch the wires at the coil as well. The positive ground system will have the wire from the + terminal of the coil to the distributor. The negative ground system will have the wire from the - terminal of the coil to the distributor. The engine will run wired either way BUT the coil output voltage will be greatly reduced if hooked up incorrectly. If the vehicle has as an amp gauge, you will have to reverse those wires as well for the gauge to read correctly. Most other gauges will read correctly assuming you aren't going from 6 to 12 volts as well. If you are going to 12 volt system as well, be sure to add a ballast resistor for the coil. You will need a voltage reducer to operate the heater fan and the radio and any other 6 volt accessories. Change all the bulbs to their 12 volt equivalent. The 6 volt wires are heavier gauge than their 12 volt counterparts and will work fine.The 6 volt starter will work fine with 12 volts. It will spin faster though.
 
#6 ·
Cape Cod Bob

I did try looking through it,found there are a lot of posts here and got all sidetracked and gave it up when my the wife had noticed my eyeballs were turning red . I decided it woub be easier to post a Qustion about it. I was right and thaks to you guys it`s looking a bit simpler than I thought making the changeover from 6V+ to 12V- ground... THANK YOU... Dan
 
#7 ·
Frisco

OK... there`s only two things left to work out now. First the coil,it only has one post on it going to the distributor,the other lead/wire is harnesed inside a braded stainless steel housing that is moulded onto the bottom of the coil and goes to the key switch and is also moulded at that end,it`s factory made like that and is not accessable for servicing. I guess I will need to get a new coil and ignition swtch for that job. Next is the generator is 6volt,probably should install a alternator and get it over with. Since there was no fuse pannel installed at the factory I should put one in there too... THANKS FOR THE HELP... Dan PS... what about the gas gauge and sending unit,is that going to need to be change out???
 
#10 ·
Elwood_DR said:
OK... there`s only two things left to work out now. First the coil,it only has one post on it going to the distributor,the other lead/wire is harnesed inside a braded stainless steel housing that is moulded onto the bottom of the coil and goes to the key switch and is also moulded at that end,it`s factory made like that and is not accessable for servicing. I guess I will need to get a new coil and ignition swtch for that job. Next is the generator is 6volt,probably should install a alternator and get it over with. Since there was no fuse pannel installed at the factory I should put one in there too... THANKS FOR THE HELP... Dan PS... what about the gas gauge and sending unit,is that going to need to be change out???
Just out of curiosity, what make and model car are you converting to 12 volt negative ground? I have an excellent article that I can either send you or re-write here (to avoid copyright problems) concerning the changeover and installing an alternator on an otherwise stock Model A Ford. The changeover is actually very simple regardless of the make and model. As to the gauges and their function; unless they are electrical gauges they will work as is. Many older vehicles used mechanical oil pressure, water temperature, amp and even fuel gauges. None of those require anything extra for them to function correctly with a voltage change.
 
#11 ·
I sent you a PM concerning the 6 volt positive ground to 12 volt negative ground conversion. Contact me if you are interested in the scanned images of the article. I can not post them here because of copyright infringement.
 
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