12 volts instead of 6 volts?

C

CurtF

Junior Member
I've been told that its ok to start a six volt 1931 Model A Ford with a 12 v. battery but don't use any lights. Is this true, or will I mess my generator up ?
Thanks, Curt
 
You will have to do something about the coil.6 volt coils don't much care for 12 volts slammed into them.If you just have a stock cutout,and not a voltage regulator,the generator will even charge the 12 volt battery.It will whip over pretty good,is there a reason you want to use a 12 volt battery instead of a 6? Don't turn on any lights,step on the brake,or blow the horn.
 
CurtF said:
I've been told that its ok to start a six volt 1931 Model A Ford with a 12 v. battery but don't use any lights. Is this true, or will I mess my generator up ?
Thanks, Curt
Click to expand...

Curt are you asking if you can "boost off" or use a 12 volt battery just as a temporary power source to start the engine? Yes you can if that is your question however it is definitely 'hard' on the entire electrical circuit.
 
CurtF said:
I've been told that its ok to start a six volt 1931 Model A Ford with a 12 v. battery but don't use any lights. Is this true, or will I mess my generator up ?
Thanks, Curt
Click to expand...

Yes it works, use to do it at my Dads garage all the time in the winter. There were lots of 6 volt cars that did not want to start when it -20 and colder.
Just make sure you get the polarity right and do not run the starter to long. also hook up the ground last on the car not the battery. A hot battery can blow up when there is a spark by it. It will not hurt the coil, some cars like my 56 chev had 12 volts to the coil for starting.
 
Thanks for the info Guys. I would assume that I have a stock voltage regulator, its just a little can on top of the generator with a simple coil that makes and breaks a contact.
The reason for my question is, I just a couple days ago got my A delivered from Arkansas to Utah, where I have been keeping it in a barn for over twenty years. Thanks to info gained here I have cleaned out the black tar gunk out of the fuel line, cast iron settling bowl, and carborator. Not having it running is frustrating, so I'm going to try starting it with a 12v. battery a few times, until I can drive, in an other car, about a hundred miles to Grand Junction, Colo., where I hope to buy a 6volt.

Curt
 
CurtF said:
Thanks for the info Guys. I would assume that I have a stock voltage regulator, its just a little can on top of the generator with a simple coil that makes and breaks a contact.
The reason for my question is, I just a couple days ago got my A delivered from Arkansas to Utah, where I have been keeping it in a barn for over twenty years. Thanks to info gained here I have cleaned out the black tar gunk out of the fuel line, cast iron settling bowl, and carborator. Not having it running is frustrating, so I'm going to try starting it with a 12v. battery a few times, until I can drive, in an other car, about a hundred miles to Grand Junction, Colo., where I hope to buy a 6volt.

Curt
Click to expand...

Curt,
Just so you know, that little can on top of the generator is not a voltage regulator:eek:. It is the cut out relay. In order to regulate the generator charging output, you must remove the band on the back of the generator and manually adjust the third brush to achive the amps needed for the driving conditions you plan to drive in. Model A's did not have any automatic/load sensing regulation for the charging circuit.

Joe,,,,
 
In addition to what Joe just said, after a 20 year rest it would be good to polarize the generator to reset it's residual magnetism. Do this by jumping a short wire across the 2 cutout terminals for 1 second.

REMEMBER, the Model A is POSITIVE ground.
 
Joe, which way do you move the third brush to increase output, and Tom, where are the 2 cutout terminals? I've magnetised screw drivers before but not this. Sorry to be so dumb but I'm just getting back into old cars and will go out tomorrow and get on it since its supposed to be warmer.
Thanks, Curt
 
You move the adjustable brush UP to decrease the output (amps). Unless you install an electronic voltage regulator, the voltage output is unregulated, but is determined by the battery as long as all connections are clean and tight and the battery is in good condition.

The cutout has one terminal going in, which is connected to the generator output stud, and on the other side is another terminal for the output. Just jump the two together for one second after the battery is connected.

Does the car have a 6 volt battery or exactly what's the 6 or 12 volt jump going to be?
 
I have been trying to decied weather to go with the orginal 6 volt system or to convert to 12 volts on the model A I am building. I have even considered changing the field coils in the 6 volt generator to the 12 volt coils you can buy so I can keep the orginal look. I have even looked at buying a regulator from fun projects and keeping the orginal generator. If what I have read here is correct I can keep everythingas orginal, I am tallking about the charging system I know about the bulbs and needing a resistor for the coil, and just adjust the third brush on the generator and it will charge a 12 volt battery. What are the ramification of just doing that and the other required changes?

Thanks
Mark
 
I'm running my roadster on 12 volts with the original generator. It isn't necessary to change the field coils in the generator to be able to run 12 volt. I use the Fun Projects can style voltage regulator. John Regan, the guy that makes the fun projects regulators told me that the 12 volt field coils were not needed and would give no advantage. The six volt field coils use larger wire. If you use a 3.0 ohm coil you won't need a resistor. I run mine positive ground and no changes to the original wiring is necessary. The starter works real good on 12 volt and the original style 20 amp ammeter will not need to be changed.The three basic needs will be a 12 volt battery, Fun projects regulator and a 3.0 ohm coil. I have run this setup for six years and heve been very happy with the results.
 
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Thanks Purdy Swoft. I have read another post by you and that is where I first read about the fun projects regulator. If I am following you after the regulator the coild, bulbs, and battery are the only other things to change. One other question, is it necessary to run as 12 positive ground and if not is there any advantage to staying positive ground?
 
I only replaced the coil , battery and replaced the cutout with the fun projects can style regulator. I am running the 12 volt positive ground regulator. The advantage of running positive ground is the fact that no wires have to be switched in any way. The car remains basicly stock. Fun Projects also sells a negative ground regulator. You would have to reverse the battery, reverse the wires behind the ammeter and the coil wires. The generator would need to be repolarized, this could be done by jumping a wire across the terminals of the cut out for a second. I have run model A's negative ground with the model A generator and cut out. It can be a pain keeping it polarized. Staying positive ground will be the easy way to go. Good luck.
 
Why fool with this, put in the battery that's supposed to be in the car, use a heavy battery cable, make sure your starter is GOOD, it will spin your motor just fine, NEVER use 12 volts, fix your starter instead and save a lot of headache and grief. 12 volts in a Model A ???..... what for.
 
I’ve had my Model A since I was 15 (and that was a long time ago) and have kept the original 6 V positive ground system even though many people have told me I need to change to 12 V. I run the Fun Projects voltage regulator and use LED headlights, tail and brake lights, and the electrical system easily keeps up with everything. I just don’t see the need to change to 12 V.
 
Wow. This is a really old thread.

I too have 6v positive ground. I don’t see the need to change anytime soon because the car runs fine.

However, I do see why many folks switch to 12v negative ground. 12v parts are easier to find and are more likely to be in stock. If you break down and happen to find a nearby non-Model A garage, the mechanics are certainly more well versed in 12v negative systems. 12v makes it easier to add modern accessories, if you are inclined to do so.

There is really no right or wrong answer for 6v versus 12v. We all use whichever has brought us the most success.


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It isn't necessary to convert to negative ground when converting to twelve volt unless you just want to run negative ground . I run positive ground , mostly because no wires need to be changed . Mine run very good on 12 volt positive ground . I use the Pertronix flame thrower coil for hotter spark . I feel that a twelve volt conversion is one of the best things that a person can do to improve the model A . I was very surprised at the improvement in performance when I converted to twelve volt and used the three OHM flamethrower coil .
 
As some have said "there is no need to switch to 12v".

But I agree with Purdy. I too use a Pertronix 12v Flamethrower. And I find it easier to find 12v bulbs, either LED or incandescent. I run 12v amber incandescent bulbs for front turn signals and Ron Francis 125/75 cp headlight bulbs.


Amber incandescent in HL for turn signal. When is the last time you have seen a 6v amber bulb?
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You're the smart one pal, if I wanted a CB radio, LED lights and a DC player I'd buy a modern car with that stuff in it. A Model A is a terrific car, been driving them since 1948, closest I get to 12 volts is when some guy passes me, that's close enough. Keep it original as ol' Ford made it, well OK, Edsel too, he had a lot to do with it.
Street rod mentality has gone too far folks
warrene
 
When I get in my car I want a REAL Model A, not a relative of a street rod, if I wanted all that modern 'stuff' I'd buy a car with that already installed.
I use 50 cp bulbs, you can buy anything from Snyder's or Mac's, any 6v bulb or whatever.
 
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