Coils and resistors

Jordan Baker · #1 05-05-09, 22:14

Hi everyone.

I just picked up a coil for my UC today and it says it doesn't require any external resistors. My wiring on the UC is back to factory specs with a resistor. Should I bypass the resistor or can I still use it. Would it affect the coil at all being "doubled" resistored. And if it makes a difference its a 6 volt positive ground system.

Thanks

Bob Carriere · #2 06-05-09, 02:41

Hi Jordan

Where did you get that coil...... last I found from the tractor dealer an TSC were clearly stamped that they must be used with a resistor...???

would make life much easier.....

Thanks

Bob

Lynn Eades · #3 06-05-09, 09:00

If its a six volt coil, and your running six volts, and it says no resistor required, then dont use one.
The original Ford coil is designed to run on 4.5 volts, and it gets this 4.5 volts, by applying 6 volts to a resistor,(in the instrument panel) out of which is delivered 4.5 volts, to the coil.
If you try to run your 6 volt coil on 4.5 volts, your high tension voltage will suffer dramatically, and it more than likely wont even fire.
Later vehicles with resistors usually worked something like this:
With a 12 volt system they would use a 12/9 volt ballast coil.
When the engine is running the coil gets a reduced voltage (9 volts) through a resistor. When the key is switched to the "start" position, the resistor is bypassed applying the full 12 volts to the coil. This effectively increases the spark at a time when it would otherwise be weakened by the load of the starter motor under cranking.

Jordan Baker · #4 06-05-09, 09:19

Coil came from Napa. Part # IC7 The cat. listed a bunch with no info as to what needed a resistor or not. I guess I will have to figure out how to bypass the resistor then.

Just to make sure. Is is the part with the porcaline or the fiber piece with wire wrapped around it.

As you can tell, electrics aren't my strong point.

Lynn Eades · #5 06-05-09, 11:10

This is your isnt it? The white bit with the fine wire wound around it.

Lynn Eades · #6 06-05-09, 11:28

If you put your volt meter onto the top nut (the one with the wire on it)(from the nut to earth) youll get your 6 volts.
From the other nut to earth youll get 4.5 volts.
Just hook your coil feed wire to the same nut that the wire is already connected to.

Jordan Baker · #7 06-05-09, 14:06

Thanks and just to confirm its the nut with the red arrow?

Jordan Baker · #8 07-05-09, 02:39

Thanks for the help. Im happy to report that I did as instructed and my Carrier fired right up. And does it ever sound "sweet" with the NOS mufflers installed.

Now I just need to sort out the wiring for the generator and I am good to go.

Lynn Eades · #9 07-05-09, 11:16

thats the right nut. Now what are the generator problems?