[AT] question on use of resistor on coil

[Ralph Goff]

Its been too many years since I did the 6 to 12 volt conversion on the old
Cockshutt 50 but I do recall that I had to install a resistor at the coil
when I changed to 12 volts. Kept the original 6 volt coil but I was advised
that if I did not install a resistor it would cause the points to burn out.
Just to confuse things further, my 1959 IH pickup has a firewall mounted
resistor connected to the coil. Yet this was a 12 volt system truck right
from the factory. Some years ago when the original ceramic resistor cracked
and I tried to replace it with one that "looked right", I found that the
truck was near impossible to start and when it did, ran terribly. I duct
taped the old resistor together and re-installed it. Its been working fine
ever since.
Not much help, just my two cents worth.

Ralph in Sask.
http://lgoff.sasktelwebsite.net/
----- Original Message -----
From: Cecil E Monson <cmonson at hvc.rr.com>
To: Antique tractor email discussion group <at at lists.antique-tractor.com>
Sent: Saturday, October 23, 2004 3:05 PM
Subject: Re: [AT] question on use of resistor on coil


> What gets me about this business, Charlie and Dean, is that
> the coil I just tried is listed as a direct replacement for not only
> AM791T but also for Delco Remy 1115379. I am just smart enough to know
> that something is fishy with this as this coil, #AM373T, is also listed
> in the Parts Catalog for my JD 2010 as the correct coil and we all know
> the 2010 was never anything but a 12 volt system.
>
> When you go to a JD dealer today and ask for a new coil for the
> 40 or the 420 or the 2010, this is what you are going to get and whether
> you have a 6 volt system or a 12 volt system doesn't matter to the parts
> man.
>
> Getting back to my original question, are we supposed to use a
> resistor with the coil in a 12 volt system or when used in a 6 volt
> system?  I think the 12 volt system needs the resistor, not the 6 volt
> but the instructions say boldly on the box "must be used with a resistor"
> which is what puzzles me.
>
> FWIW, Dean, I have full sets of manuals for all of my JD tractors
> - all three of them. grins. I bought the manuals shortly after I bought
> each tractor so they would be as current with the model as possible.
>
> Cecil
> --
> The nicest thing about telling the truth is you never have to wonder
> what you said.
>
> Cecil E Monson
> Lucille Hand-Monson
> Mountainville, New York   Just a little east of the North Pole
>
> Allis Chalmers tractors and equipment
>
> Free advice
>
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