- Thread starter Bud W
- Start date
Janicholson
Well-known Member
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
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
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
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
Well-known Member
In my post I indicated a 1965 Chevrolet Impala with small V8. That resistor will be fine and not expensive. Jim
Heat Houser
Member
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.
the tractor vet
Well-known Member
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
Well-known Member
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
Well-known Member
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
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
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??
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-known Member
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.
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
Well-known Member
NAPA number MPE IC 10SB Less than 25$ Jim
I just looked up the NAPA item you mentioned and see your trying to save me some bucks on a coil. Thanks but I would gladly give someone $300 just to get this @#@ tractor started.I'm hung up on the darn external resister. I want a 12 volt coil with the wiring connections on one end and the distribtor output on the other end like the original equipment. I feel like I've wasted a lot of your time and others and I'm just too dense to understand this darn resister issue.If I buy the 12 coil off this site do I need an external resister and if so how do I install it??
Janicholson
Well-known Member
If (and only if) the resistor you have is good should you use it. If it has about 2 ohms of resistance, it is good. Use it. If you aren't sure how to read ohms, use a test light as follows: remove the wire from the coil connected end of the resistor. Hook a wire from the battery positive to the other end of the resistor. use a test light to ground to the disconnected end of the resistor. If it lights the resistor is good. Use it. If it lights only on the battery connected end and not the other it is bad, Get a new one as specified above.
I would replace the coil with the one above. It is fine for the use of the tractor and was chosen for appropriate values not price. Jim
I would replace the coil with the one above. It is fine for the use of the tractor and was chosen for appropriate values not price. Jim
John G. Hasler
Member
If you install a 12 volt coil of the type that has an internal resistor then you should remove the resistor that you are using now.
Janicholson
Well-known Member
Dear John With no disrespect, there are no internal resistors in coils. The 12volt for use with no external resistor does not imply that there is an internal resistor. There is not. It is just wound such that it can operate on full 14.2 volts of an operating charging system.
Bud's tractor has a 6 volt coil of unknown operational status. (we think it is bad)
he needs either a new ballast resistor, and a new coil, or a new coil only. If he purchases a 12v No external resistor required coil he can dispense with the ballast resistor all together.
That is part number MPE IC 14SB (no resistor required 12v. Jim
Bud's tractor has a 6 volt coil of unknown operational status. (we think it is bad)
he needs either a new ballast resistor, and a new coil, or a new coil only. If he purchases a 12v No external resistor required coil he can dispense with the ballast resistor all together.
That is part number MPE IC 14SB (no resistor required 12v. Jim
Janicholson
Well-known Member
MAPA number MPE IC 14SB is 12v no resistor needed.
If you buy this coil it hooks directly to your ignition switch on the + side and to the dist on the - side. No resistor is needed.
It will be OK Jim
If you buy this coil it hooks directly to your ignition switch on the + side and to the dist on the - side. No resistor is needed.
It will be OK Jim
John G. Hasler
Member
> there are no internal resistors in coils. The
> 12volt for use with no external resistor does
> not imply that there is an internal resistor.
> There is not. It is just wound such that it can
> operate on full 14.2 volts of an operating
> charging system.
I know that, but the manufacturers often describe them as if they do have an internal resistor. It"s simpler to accept that description than to explain that they are wound with very fine wire.
> If he purchases a 12v No external resistor
> required coil he can dispense with the ballast
> resistor all together.
That"s what I thought I said.
> 12volt for use with no external resistor does
> not imply that there is an internal resistor.
> There is not. It is just wound such that it can
> operate on full 14.2 volts of an operating
> charging system.
I know that, but the manufacturers often describe them as if they do have an internal resistor. It"s simpler to accept that description than to explain that they are wound with very fine wire.
> If he purchases a 12v No external resistor
> required coil he can dispense with the ballast
> resistor all together.
That"s what I thought I said.
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