Reverse a 12v to a 6v possible?

[jchochole]

Hi Gents,
My new Model A is 12v and the previous owner is lying down permanently, so I can't talk to him. His conversion to 12v is incomplete and no lights were changed, all I have is a 12v alternator. If I go back to 6V Positive ground, and replace my alternator to 6V pos ground, then I think all I need to do is take off this voltage converter.

Am I on the right track here?

Thanks,
Jim

[CarlLaFong]

Yup

[Purdy Swoft]

Most will probably suggest changing back to 6 volt . I know that I would never change back , though it is simple to do .I'm getting ready to change two more of mine to 12 volt . A 12 volt system is more powerfull and reliable . Though the six volt system has worked for over 80 years on the model A , it is a bare get by . Why do you think that the automakers changed to 12 volt nearly 60 years ??? There is more to it than being able to save money by using smaller gauge wire . Six volt batteries are geting harder to find and usually cost more than a dependable, more powerfull 12 volt battery, that can be found anywhere .

[Keith True]

I see you have modern type plug wires.That means a different cap,which in itself is not a problem.Pull it off and make sure somebody hasn't installed an electronic ignition setup too.That will care if it is 6 or 12 volt.

[barkleydave]

Larger gauge wire is required for a 6 volt system. The main reason for mfg. changed to 12Volt was for that reason. 12 volts gives more punch per amp than 6 volt.
Same principle with AC a 220 circuit uses smaller gauge wire and longer runs are possible with less line loss.

Europe pretty much started the Positive Earth standard. There is no advantage either way except many newer accessories will not run with reversed polarity so US standardized production to Negative ground when they went with 12 volts systems.

[1931 flamingo]

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That's not a voltage converter, it's a ballast resistor so you don't burn out the coil.
Paul in CT

[jchochole]

Okay guys, here's what is inside my dist cap. Plus, I checked and all dash wires were flipped: the two wires inside the ammeter were backwards from Les's book and so were the coil (+) and (-) wires, when a car goes from pos. ground to neg. ground- I didn't think that stuff had to be flipped?

Thanks- can I still run these modern plug wires to the dist? Or do I need a whole new dist cap, top cover and wire? Anything else?

[Patrick L.]

Its a simple change back to 6v as long as the previous owner left the 6v wiring the same. If you're going to go to 6v I'd recommend staying with a generator. Actually I'd recommend that even if staying with 12v.

The 'voltage converter' attached to the coil is just a ballast resistor that can be removed. It is used to reduce voltage from 12 to 6 to the points.

[Bob C]

You have to reverse the wires on the ammeter or it will read backwards.

Bob

[jchochole]

I went and corrected the wiring at the terminal block and inside the dash as per Les Andrew's book. Besides that, will the modern plug wires and cap be a problem?

Jim

[Purdy Swoft]

Its just as simple to change back to 6 volts as my friend Patrick says in post number 8 . you could either use an original generator or buy a replacement positive ground alternator. connect the wire from the switch to the plus side of the coil for positive ground . remove the ballast resister . swap the wires behind the ammeter for positive ground and install a 6 volt battery . connect the cables positive ground and that should do it . good luck , whatever your choice .

[Chuck Sea/Tac]

No the modern wires and cap will not be a problem

[Mike V. Florida]

Originally Posted by jchochole

If I go back to 6V Positive ground, and replace my alternator to 6V pos ground, then I think all I need to do is take off this voltage converter.

Am I on the right track here?

Thanks,
Jim

Originally Posted by jchochole

Besides that, will the modern plug wires and cap be a problem?

Jim

Like they said, easy as pie, remove the ballast resistor that drops the voltage and the cap and wires will work 6 or 12 volts.

[jchochole]

Sounds great guys- I ordered a positive ground 6V alternator and have re-arranged all the wires as per Les Andrew's stock configuration in the Model A manual, and I am headed back to stock!

Thanks for all the answers and support! I don't know where I'd be without all the great help!

[Tom Wesenberg]

If you switch the distributor cap back to original, be sure to buy the bronze (more reddish) straps, rather than the softer brass straps.

[jchochole]

I have a nice set of older reproductions which are very solid and thick. Thanks for the tips!

[eagle]

If someone converted it to 12 volt, they probably were having an issue on six. Remove all connections and clean to shiny. Put a ground strap from starter bolt to frame. Either make one up with good quality fine strand copper wire or use a braided ground strap, available at any auto parts store.

[jchochole]

Eagle,
What sort of gauge or wire thickness would you recommend for a ground strap off the starter?

Jim

[Glenn Thoreson]

Use the original type braided ground strap. Run it from anywhere on the engine to the
frame. A strap from the body to the frame is a good idea, too. If you can't find a strap a regular battery cable of proper length is fine. Clean, bare metal and tight connections are a must.

[BILL WILLIAMSON]

MANY things can be UN-DONE, except for SCRAMBLED EGGS!
Bill Cook