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12 Volt Starter

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  • 12 Volt Starter

    What's everyone doing for a starter with 12 V? I see Snyder's sells a reduced gear new starter that is a little pricey. Have to install a electric switch to pull in the solenoid.

  • #2
    12 volts will spin a 6 volt starter a little fast with no problems, just make sure you retard time with the lever up :-)


    • #3
      You have several options:

      1) Rewire the original starter from parallel fields and armature to series. This is pretty much what the entire auto industry did to differentiate 6V and 12V starters. Works well, cheap.

      2) Use a Bendix spring as a ballast resistor bolted on top of the starter switch. Scary!! Watch it glow red at night while cranking.

      3) Use a 4 foot length of #6 from the battery to the starter switch. This induces considerable voltage drop at very high amperage draw. Again, scary.

      4) Do nothing, let it crank like crazy. This is the go-to option for most model A guys. You will have four times the torque, not just two time as much because P = I x I x R. Then your Bendix will fail from all the slamming and you will complain about how crappy original Bendix drives are. After replacing it with a "modern" (old tech) barrel drive, that 'new' thing will jamb in the extended position from the terrible 4X engagement shock. Good luck then.

      5) Spend $$$ for the gear drive you speak of. It will engage the wrong side of the ring gear (no engagement mesh taper). After having to rock the car a few times because of this you will either pull the engine and flywheel to reverse the ring gear or spend all day trying to moto-tool a chamfer on the back side of the ring gear teeth through the starter mount hole in the flywheel cover casting..

      I have both 6V and 12V A's. I went with #1.

      Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.


      • carolinamudwalker
        carolinamudwalker commented
        Editing a comment
        Mike , I am one of the guilty ones that are running a 6 volt starter on 12 volts. The Bendix does slam into gear with a lot of force. When you say rewire from parallel to series do you mean to re-wire the field coils or replace the field coils with a set from the venders? Can you elaborate a little on the rewire option? I kike cheap Bob

    • #4
      Thanks Mike,
      Since I am gathering parts for my test stand, I guess option 1 or 2 is good. I haven't got a flywheel yet either. Good info. I didn't think of the reverse mesh of the original starter. I haven't held one yet to look at.


      • #5
        carolinamudwalker - Original 6V starter motors have a right and left hand field connected in parallel. You cannot simply rewire the existing fields. You would need two starters and use both left, or both right fields in one, wired in series. Easy way: just buy the new 12V fields from a vendor. You will still have much more starter power than the original 6V on 6 volts, about double. You will not have the vicious 4X engagement slam you now have.
        Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.


        • #6
          I have used the stock 6v starter on 12v (with the addition of the "modern" Bendix). While it definitely turned the starter faster, like others stated above, tended to slam into the ring gear. The teeth in the ring gear showed severe wear after several years of use that way. I am now using one of the gear reduction starters that Snyder's sells, (with a new ring gear) hopefully this will solve the ring gear wear problem.
          Alaskan A's
          Antique Auto Mushers of Alaska
          Model A Ford Club of America
          Model A Restorers Club
          Antique Automobile Club of America
          Mullins Owners Club


          • #7
            Forget the starter and just hand cranker
            It's good exercise to boot
            3~ Tudor's & 1~ Coupe
            Henry Ford said,
            "It's all nuts and bolts"
            "Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible."

            Mitch's Auto Service ctr


            • dmdeaton
              dmdeaton commented
              Editing a comment
              I would break my arm!

          • #8
            the issue I had with the 12 V field coils was that the copper bus straps were not the correct length (too short); there were several other fit issues as well. It is not a simple swap-out.
            These coils are made for something else.
            I ended up aborting the project
            Last edited by tbirdtbird; 11-21-2017, 11:34 PM.


            • carolinamudwalker
              carolinamudwalker commented
              Editing a comment
              Oh crap, I was just getting ready to order 12 volt field coils and complete rebuild kit. My problem is I hate paying the shipping charges both ways by shipping my starter in for a rebuild, plus I like doing things myself.

            • tbirdtbird
              tbirdtbird commented
              Editing a comment
              Bob, I spent a lot of time screwing around trying to make these 12V coils work. Never again.
              Brattons sends their starters to some starter shop somewhere where they are converted by a couple guys who have extra parts, brushes with longer leads, etc etc and these guys can pump them right out the door.
              I don't usually give up, but I did on this conversion. Ever try to make a copper strap longer?
              If I ever thought about it again I would ship it off to Brattons and let them mess with it.
              Same issue we always have, the parts we have access to don't always fit properly

          • #9
            Four cars in our club have had issues with 12volt batteries dirivng 6 volt starters. 2 of them pushed the starter ring off the flywheel. One broke the Bendix drive, original style. The 4th one, mine, was starting to push the starter ring off. I noticed it while the engine was out for other work. I will be converting the starter to 12volt.


            • #10
              Can you buy an original style 12V starter without a core?


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