The Ford Barn

RAF · 08-24-2017, 06:05 PM

Looking for some help on 6 volt to 12 volt conversion on 1940 Ford with flathead V8. I am going to use the stock wiring harness as it is fairly new, have converted to 12 volt generator and starter along with regulator, coil, voltage drops for gauges, bulbs etc. Question is what do I do with the resistor assembly? Will it work with 12 volts, do I need it and if not what do I do with all the wires attached to it? First time doing a change like this and any help appreciated. I did searches but couldn't find what i was looking for. Thanks.

Lawrie · 08-24-2017, 06:22 PM

I think it depends on what coil you are using,talk to Bubba on this forum.he will put you on the right track.
Lawrie

JeffB2 · 08-24-2017, 07:07 PM

A guide like this may be handy: http://darksidersrealm.forumotion.co...egative-ground

JSeery · 08-24-2017, 07:59 PM

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No, you do NOT use the existing ballast resistor with a 6 to 12v change. The requirement for a new ballast resistor depends on the coil you are using. You need somewhere in the range of 3 ohms of resistance in the ignition circuit, so if the coil is say 1.5 ohms (a common type) then you need a 1.5 ohm ballast resistor. If it is a 3.0 ohm coil then you do not use a ballast resistor. It is best to measure the coil resistance and go from there.

The original ballast resistors are in the .5 ohm range.

08-24-2017, 06:05 PM	#1
RAF Member Join Date: May 2010 Location: Western Mass. Posts: 42	6 volt to 12 volt conversion Looking for some help on 6 volt to 12 volt conversion on 1940 Ford with flathead V8. I am going to use the stock wiring harness as it is fairly new, have converted to 12 volt generator and starter along with regulator, coil, voltage drops for gauges, bulbs etc. Question is what do I do with the resistor assembly? Will it work with 12 volts, do I need it and if not what do I do with all the wires attached to it? First time doing a change like this and any help appreciated. I did searches but couldn't find what i was looking for. Thanks.

08-24-2017, 06:22 PM	#2
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,212	Re: 6 volt to 12 volt conversion I think it depends on what coil you are using,talk to Bubba on this forum.he will put you on the right track. Lawrie

08-24-2017, 07:07 PM	#3
JeffB2 Senior Member Join Date: May 2010 Location: Phoenix,AZ Posts: 1,417	Re: 6 volt to 12 volt conversion A guide like this may be handy: http://darksidersrealm.forumotion.co...egative-ground

08-24-2017, 07:59 PM	#4
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: 6 volt to 12 volt conversion Sponsored Links (Register now to hide all advertisements) No, you do NOT use the existing ballast resistor with a 6 to 12v change. The requirement for a new ballast resistor depends on the coil you are using. You need somewhere in the range of 3 ohms of resistance in the ignition circuit, so if the coil is say 1.5 ohms (a common type) then you need a 1.5 ohm ballast resistor. If it is a 3.0 ohm coil then you do not use a ballast resistor. It is best to measure the coil resistance and go from there. The original ballast resistors are in the .5 ohm range.