Converting to 12 volts neg ground

kingbee

kingbee

Senior Member
OK, i've got the alternator, battery, all replacement bulbs, 30 amp ammeter, voltage dropping resister for the horn and 12v. coil.

Is there anything I'm missing, and anything special I have to do other than install what I have?

I'm putting in a hidden stereo system and air conditioning in my coupe, thus the 12v need.
 
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Doesn't one need to put 12 volt field coils in the starter? I understand some guys are having Bendix failures with the 12 volt conversion. See post by a gentleman on Fordbarn named Pat Martone. He's doing this now.
 
i am using 12vdc & 6vdc starter . im using the v8 style starter drive . it starts so quick i cant hardley get off the button fast enuff . no problems for 2 yrs now . i love the 6v starter !
 
This is from Ken at Kens Garage.


Battery


Any good 12 Volt battery will do as long as it will fit your battery box and hold down. I selected a 72 month, 675 cranking amp, universal battery.​

Generator


I installed a GM 63 Amp Alternator with an internal self exciting voltage regulator. The hook up is one wire, the same as the existing generator. You will need to make two small brackets to mount the alternator or you can use two shackle bars and drill out for the proper size bolts. An alternator pulley can be purchased from your friendly Model A parts supplier.
​

Starter


No modifications are necessary to the starter. Just touch the pedal and enjoy really fast starts.​

Ammeter


I changed the standard 20 amp ammeter to a 30 amp ammeter as an alternator will peg the standard meter. You must reverse the leads on the ammeter due to the change in polarity of the battery. Your neighborhood Model A parts supplier carries the 30 amp ammeter.
​

Headlights


Since I installed an alternator I opted to go all the way for headlights and convert to Halogen bulbs. The conversion is relatively easy. You can purchase a kit to modify your existing reflectors or you can purchase new reflectors with the Halogen sockets installed. You must install an alternator to successfully operate Halogen bulbs.
6 Volt kits are available. What a pleasure to be able to really see while driving at night.
​

Ignition


You could install a 12 volt coil and a resistor to reduce the voltage to the points.
I elected to install a PerTronix IGNITOR electronic ignition system. This is an extremely easy system to install as it fits entirely inside the distributor; no outside boxes are required. Kits are available for the standard Model A or B, early V8, and Mallory distributors. Both 6 and 12 kits are available.
Kits are furnished with a new coil as the correct coil resistance is very important for proper operation. Kits are distributed by: Remund Ignitions, Inc.
P.O. Box 857
Lemon Grove, CA 91946-0857
(619)460-3620
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Horn


Getting the horn to work properly was the most perplexing part of the conversion. I tried several "voltage reducers" from the local parts stores but none could handle the current demands of the Model A horn. I finally purchased a 0 to 2 Ohm variable power resistor with a 100 watt rating from an electronics supply house. I selected a variable resistor in order to optimize the voltage to the horn.
The resistor I purchased was am Ohmite D100K2RO ($15.87) with two Type 12 brackets ($0.55 ea.) (Newark stock nos. 13F671 & (2) 13F099) from:
Newark Electronics
1-800-463-9275
Branch offices of Newark are located throughout the United States. Minimum order is $25.00. An alternate approach would be to puchase a 12 volt horn.
​

Light Bulbs


The following bulbs can be used with a 12 volt system: Cowl, Tail, and Dash Lights - #89, 6 cp
Dome Light - #67/97, 4 cp
Stop Lights - #1156/10, 32 cp
​

Turn Signals


If you have a Signal-Stat turn signal it will be necessary to change the flasher to a Signal-Stat #180 and the bulb to a #1445.​
 
I have a listing of all the bulbs both 6V and 12V, plus an electrical parts list that contains the link to an electronic regulator for the horn and wiper(if electric) that works better than a standard dropping resistor. Send me your email address to jrelliott42@gmail.com. It may be a while as will be on vacation for the next 4 to 6 weeks. The information is stored on my desktop computer and not my laptop that I will be taking with me. When I get back will send you the information.
 
There is no real need to replace anything on the starter going up to 12V. I have been running 12V for about 15 years and have had no starter failures in over 50,000 miles.
 
If you car starts quickly, you MAY get away with a 6V starter, but its not the best situation. Your better off installing 12V field coils to save ware and tear on the starter shaft, bendix drive and flywheel ring gear. If don't covert to a 12V starter look at a barrel drive to replace the Bendix drive.
 
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