Coil External Resister

[Bud W]

Do the original style 6 and 12 volt coils for sale on the site require an external resister? I'm not aware of an external resister on my original existing coil-where would it be located from the factory?
 

[Janicholson]

The resistor is located near the coil, if not on it.
The location does not matter much as long as it can get a little air circulation. Using a mid 1960 Chevrolet resistor is a good choice. The original wire from the key is black. There is a bypass wire as indicated on the diagram, and my diagram as well.
A 12v coil with "for use with an external resistor" written on it, or with a resistance of 1/5 to 2.5 ohms needs a resistor. A 6v coil is the same in every way as that 12v just described, and needs a resistor.
A 12v coil designed to operate with no resistor is not to be used in this application, as it has no way of boosting starting primary voltage when cranking. It does not have a internal resistor. Jim
 

[Bud W]

Jim
I'm looking at page 50 of the TC44 Parts Book and I don't see any resisters. Would it be located somewhere else? Do you have a parts number? I'm thinking of eliminating the Ballast Resister and installing a 12 volt original design coil from the new parts area of this site and I guess I would need to buy a resister also but I just don't know what to by. Thanks Bud
 

[Janicholson]

In my post I indicated a 1965 Chevrolet Impala with small V8. That resistor will be fine and not expensive. Jim
 

[Bud W]

But Jim where in the heck does the resister go? I can't find one on this tractor or any of my others ( 2 Cubs and a SMTA ).Bud
 

[Heat Houser]

What tractor are you dealing with? My JD4010 gasser has the resistor as part if the ignition switch. My 560 farmall has it mounted by the coil. My B farmall does not have one as it is a 6 volt system.
 

[Bud W]

52 Super C
 

[the tractor vet]

They WERE NOT USED on six volt systems , I H never changed coils when they went to twelve volt they added the resistor into the systems . when they went to the twleve they put the resistors next to the coild and like said above the BLACK wire hooks to it and there is a WHITE wire coming from the R post on the starter tha bypasses the resistor to give the coil a shot of straight 12 for a hot start when you press the starter button . Once you let off the starter button all the juice then goes thru the resistor and the 12 volt feed is cut down to 6-8 volts to the coil. to save the coil and the points. You can use either a GM resistor or one off a Mopar that has the two terminals They did not go to this till the 460-560 .
 

[gene bender]

Some brackets for the coil have the tab for mounting the resistor or you can buy a 12v coil that doesent need one. It will be marked no resistor or something like that.
 

[Janicholson]

Mount it on the same bolts that hold the coil. The one I indicated has a nice mount that works.
On a Super C there is no bypass. If you really want the bypass you need to remake the starter to use a relay and small push button. Jim
 

[Bud W]

Vet
So as long as I replace my 6 volt coil with another 6 volt unit no problem ? I was hoping I could eliminate the 12 to 6 volt resister before the coil and just install a 12 coil but sounds like your saying if I do that I need to add another resister somewhere in the coil circuit ans since I really don't know how to do that I better just stay 6 volt on the coil. Correct??
 

[the tractor vet]

Well i am sorta in the dark here , What tractor are you working on for one and for two is it a six volt now or is it a 12 volt . ?????? IF it is still 6 volt then no resistor is needed with a six volt coil. IF it WAS a six volt system and has been changed to twelve then if your running a stock coil from the six volt system then it needs a resistor . If you have replaced the six volt coil with a twelve volt coil it should say on the side of the coil if it DOES NEED a resistor or not . A couple years ago i broke down and switched my S/MTA over to 12 volt and all i added was the resistor . It is installed behind the STOCK coil that the S/MTA came with , and all i had to do was take the ing. wire off the coil and hook it to the resistor and make up a short jumper wire to go from the resistor to the coil.
 

[Bud W]

Sorry , I seem to have a problem in my explanations. What I have is a 52 Super C that has been converted to 12 volts ( 12 volt battery , 12 volt alternator and a 12 to 6 volt resister in the circuit to the coil. The tractor will not start and I suspect a bad coil since I can't get spark to jump from the coil to ground or from the plug wires to ground. I thought if I was going to buy a new coil why not just go with a 12 volt coil and eliminate the 12 to 6 resister.There is an original looking 12 volt coil in the parts area of this site but they can't tell me if I need a resister with it so I'm stumpt. HELP
 

[Janicholson]

NAPA number MPE IC 10SB Less than 25$ Jim
 

[Bud W]

So I eliminate my current 12 to 6 volt resister , install a new 12 volt coil and add the new resister-right? Is this new resister installed just like my existing one ie in the line to the coil input?Thanks