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Generator Conversion: 6 volt to 12 volt

Discussion in 'The Hokey Ass Message Board' started by Eroc, Oct 23, 2005.

  1. Eroc
    Joined: Jun 19, 2005
    Posts: 60


    I'm looking to convert my 6 volt Generator to 12 volt. Any ideas what i should pay?

    Also, if anyone can recommend a shop in SF Bay Area for this I'd appreciate it.
  2. TV
    Joined: Aug 28, 2002
    Posts: 1,451


    I payed $50.00 to convert my 32. He had to order new fields, change them and put it back togeather and test it. The rotor stays the same.--TV
  3. shoebox72
    Joined: Jan 24, 2003
    Posts: 1,491


    Actually there is no "need" to convert your generator to 12v. Generators are stupid & will charge whatever volts you throw at them. Just use a 12v voltage regulator & the gen will do the job. I've done this many times with no problems.

  4. Bugman
    Joined: Nov 17, 2001
    Posts: 3,483


    What he said. While testing my stock Mopar 6V generator, I had it momentarily putting out 17 volts and over 100 amps. It'll run 12V no problem, just swap the regulator.

  5. I have done the conversion twice, but I was lucky when I did (10 years ago) because it was still kinda easy to find a 12v generator, just swapped 'em out, the old 6 volt starter loved the increase :D

    I was cheap and instead of using the lil fancy pants voltage reducer for my vintage radio, I used a switch from an old heater blower motor (speed)...set it on med. and had instant 6 volts to my 1948 chevy sure there will be someone scoff at such backwoods engineering, but it worked for me.:p it was nice when you could get stuff like that for free from the local pick-a-part salvage (sigh).

    Patrick's antique cars & trucks has a write up on doin' it like suggested earlier, probably the best way.
  6. DrDano
    Joined: Jul 10, 2003
    Posts: 696

    Alliance Vendor

    I'm going to stand on the other side of the fence concerning the voltage regulator and just changing it instead of doing the fields too.

    Just changing the regulator is not a wise idea. Eventually, you WILL burn up the fields in the generator. Time it takes to burn the fields up depends on how hard the generator is run, but it will eventually happen. If you turn on every power accessory in the car, say the heater, lights, everything and just drive, you'll burn it up in no time. The running joke at the shop here is "7 miles" -- typically how far a customer will get out of town after repeatedly refusing to have their fields changed and stating "I only need to change the regulator". he he.

    If though, you have a car that is only driven on sunday when its nice with no power accessories and only to the local cruise a few miles away in the daytime, your generator might last a long time. Kinda like running a 6v bulb in a 12v outlet, may last quite a while until you try to use it hard for a decent period of time. Then *pop*.

    It's best to change the fields in the generator and have the entire unit looked at at the same time to avoid the risk of getting stranded somewhere on the road.

    BTW, I PM'ed you about having our vintage auto electric shop do the job for you.
  7. Abomination
    Joined: Oct 5, 2006
    Posts: 6,701



    mr bill (Jan 5 2000 2:11PM) 6V generator to 12V
    Has anybody changed their generator to 12V? I took mine to a repair shop to be converted and I was told that the existing field coils are too short to convert unless I went with a longer case. Since a longer case will not fit with my dual carb setup I am wondering what to do. I dont want to use an offset mount as this will require changing the fan set up. I am thinking that maybe I should keep the 6V. Any ideas?

    Converting gen. V EK: Converting a 6V generator is pretty simple since only the fields HAVE to be changed. Use the 12V generator fields from early V8 Falcon-Comet-Mustang generators... they bolt up in the 6V generator case. (If you're running a '39 or '40 generator, you'll have to drill a hole for the ground since these generators are only two post units and the fields are wired for 3 posts.) Someone said the cases themselves are interchangeable if you drill a hole in the case for the locating pin. I don't know if that's true or not since I've never done one that way. (I usually am working on a chrome generator and want to retain the chrome case.) The armatures for the 6V flathead and the 12V generators bolt right up and will work in the 12V generator.... to a point. The 6V armature wiring is roughly twice as heavy as the 12V. No problem here (except you can't use a 12V armature in a 6V generator... it's a one way interchange.... the armature wire size is too small). If you do use the 6V armature for 12V, the generator will only produce about 75%-80% of the amps a 12V armature would. This is because there is one(if I remember correctly) less commutator bar and winding in the 12V armature than in the 6V. This reduces the amount of amps the generator can produce. Naturally, the voltage rating of the regulator must match the voltage rating of the generator. New voltage regulators for 12V generators are nearly all electronic. Whereas the 6V are all mechanical as far as I can determine. The electronic are not affected by heat or cold, but the mechanical are really affected by heat and cold. The electronic are virtually trouble free. Mechanical units give some problems from time to time and have to be re-adjusted as the springs etc. weaken with age etc.. I wish I could find a 6V electronic one. Anyone out there know of any???? Hope this is of some help to those converting..... rumble seat
    Big AL Neenyo likes this.
  8. my question is i have old yale forklift with chrysler 6v system and it sounds like with 12 regulator it will keep 12v battery charged. it only gets used occasionally.
  9. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    Member Emeritus

    I did a tech post on this for ford flatheads several years ago complete with pictures but alas my pictures will not show anymore. I converted mine for free. I like free!
  10. 19Fordy
    Joined: May 17, 2003
    Posts: 7,077


    Here's one approach I rec'd from a fellow (Ed) on Fordbarn.
    Re: Converting starter to 12 v
    Jim, I got a rebuilt starter from O'Rileys to use the case. It was for a 1964 Ford Galaxie; 390 cu in. engine. The part # is 03-0214 and the line is ULT. Cost was $39.99 plus 20 bucks for the core. So, for 60 bucks, you can have a 12 volt starter that works great. Any other questions, just email me at:

    Also, read through these posted threads on Fordbarn.
  11. is their any better than others 12v regulators? my application is mopar on a chrysler industrial engine model 30.
  12. It is silly to argue about converting a 6V to 12V you just throw 12v fields in the 6V generator. Yes you still are out the cost of the 12V fields and yes you still have to buy a 12v regulator but sometimes you just have to ball up and do something the right way.

    it is a simple conversion and it is not costly it shouldn't cost more then the 30-60 dollar range.
    Big AL Neenyo likes this.
  13. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope

    For a Dodge Six there are millions of 12v generators out there, why not just find one at a wrecker? Any Mopar from '57 up to about 64 or so had 'em. Napa will still stock them, I would think.
  14. I can't simply replace generator or upgrade to alternator since I have hyd. Pump mounted on back of it. Gen has this stamped on it CCW 6022 S 4U.

    Attached Files:

  15. So if I convert a Delco 40-amp 6V generator with 12V fields, I can expect it to put out about 30 amps?
  16. On my 53 Merc flathead, I went to NAPA and bought a rebuilt 63 (I think) Ford truck DSCN1317.JPG 6 cyl generator, machined a little off the pulley key width half way down and put the early front end on it - also cut the mounting ear off the back. Looks stock.
  17. Would anyone know of a shop in the Atlanta area that can convert my 6 Volt 1939 Chevrolet truck generator to 12 volts? I would like to keep everything as original as possible except for the electrical.

  18. Rooster23
    Joined: Jul 24, 2019
    Posts: 1


    For my truck, I want to keep it 6v but run a radio, cb, compressor, etc. I had the idea to run my stock 6v generator with it going to both 6v and 12 regulators. The 6v regulator would go to the battery, and the 12 to a small motorcycle battery in the floorboard. I’m told these generators can handle well over 12v. Also what about running a 12v generator in the same configuration? Thoughts?
  19. Inked Monkey
    Joined: Apr 19, 2011
    Posts: 1,827

    Inked Monkey

    You'll burn the field coils right quick. 6v field coils can be run with the 12v regulator with minimal electrical components. With all that extra stuff, you'll fry them.

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