[AT] 12-volt conversion

[Mike Sloane]

I completely agree with Bob's comments and would only add that, if your 
tractor has an ammeter, the wires need to be swapped to get the correct 
charge indication with negative ground. Generally speaking, if you buy a 
"reconditioned" or "remanufactured" starter at an auto parts store, they 
will have a box of assorted pulleys behind the counter somewhere - get 
the smallest one you can, as your JD engine turns over MUCH slower than 
any car engine. On the last conversion I did (on an IH tractor), I 
discovered that the old Delco-Remy generator pulley fit on the new 
Delco-Remy alternator, which was good news. Generally speaking, the 
hardest part of the conversion will be fooling around with the mounting 
brackets to get the pulley lined up with the engine pulley. If you don't 
them them lined up exactly right, the belt won't last very long. I have 
been spending the extra few dollars and buying a "universal alternator 
mounting bracket" from "T.H.E. Company" <www.the-co.com> and modifying 
the adjustment arm with the help of a big hammer and vise. I find that 
mounting the alternator sometimes requires a different size belt, so 
don't get hung up on using the original belt - you may have to buy 
several different size belts, try them, and return the ones that don't 
fit. Most shops won't mind, as long as you keep the unused ones looking 
nice and clean. An image of an alternator and mounting bracket I did on 
my Farmall 340 can be seen at 
<http://public.fotki.com/mikesloane/farmall_340/340_upgrade_09.html>

Nobody has mentioned the wiring. If your JD has a cutout or voltage 
regulator, you can actually use that wiring in the new installation - 
just run the "Bat" wire from the alternator "bat" terminal and splice 
that wire to the wire going to the ammeter from the regulator/cutout. 
What I do is just use a small nut and bolt through the two wire 
terminals and put some tape or shrink-wrap over the splice for 
insulation. That way, should anyone want to "restore" the tractor, they 
can just undo the connection and put everything back. I also keep the 
old generator and regulator in the box the alternator came in for the 
same reason. (That is only one reason my barn is so full of Stuff!) If 
you voltage regulator has an "L" terminal (lights), you are going to 
have to run that connection to either the ammeter or some other "hot" 
connection in the charging circuit. I have converted a JD 40 and MT but 
never an A or B, so I can't help with specifics.

Mike

Robert L. Holtzer wrote:
> I used a 1961 Ford 12v generator with voltage regulator on my 47 
> B.  Changed lights to 12v.  6v starter has done very well and really 
> turns over!  Used a medium duty 12v battery negative ground -- fits 
> under the seat just fine.  With the magneto, no ignition changes needed.
> 
> To do it over again, I'd suggest a single wire GM alternator -- I 
> used one from a Buick on my Farmall MD.  The JD B might require some 
> pulley changing to get sufficient alternator rpm to kick into charging.
> 
> Bob Holtzer
> 
> At 06:41 PM 12/5/2008, you wrote:
>> Can anyone give me (for a buddy) some pointers on doing a 6 to 12-volt
>> conversion on a '43 JD, electric-start B?
>>
>> What exactly will need to be changed besides adding an alternator?  Any
>> favorite brand/types of alternators you would suggest?
>>
>> Any websites that you know of that give detailed instructions?
>>
>> Thanks!
>>
>> Dick Day