Whats going on here? Resistor placement

[Nyquil Junkie]

The owner has this ballast resistor wired between the coil and the distributor. The tractor is converted to 12v with an alternator, and a negative ground. The tractor starts and runs just fine.

Why would they have put this here? I've been reading this forum and I'm not sure what reason they would have for doing this. The only thing I can think of is that the coil is an old 6v coil? or does it have something to do with the distributor?

 

[rvirgil_KS]

In theory the resistor should go between the switch and the coil. Due to low resistance of the resistor it will work where it is but possibly not as efficient.

One guess is that the person who installed the resistor did not understand it's purpose or reason for where it is placed.

 

[Bruce (VA)]

Amazing.

It would be just as effective being wired to the seat.

The purpose of the resistor is to reduce current to the coil, NOT the points.

Just remove it. Your coil has been running that way for a long time, so it might be a 12v coil. Check and see; if it's 3.25 ohms or more on the primary, it's a
12v coil. If it's less than 2.5 ohms, it's a 6v coil and you're lucky.

If you've been lucky and don't want to press it anymore, get NAPA p/n IC14SB, a 12v coil w/ no external resistor required.
75 Tips

 

[Nyquil Junkie]

Well its been running like this for years the dude said so, due to me being pressed for time picking it up, lets hope it runs one more time to get on and off the trailer. :lol:

But, when it lands here, I will certainly remove it and put the 12v coil you suggest on it. Anytime I tempt fate I usually lose.

Thanks!

 

[deanostoybox]

Being it is a series circuit it matters not where it is in the circuit, it preforms exactly the same function.

 

[JMOR]

(quoted from post at 13:32:08 08/04/22) Well its been running like this for years the dude said so, due to me being pressed for time picking it up, lets hope it runs one more time to get on and off the trailer. :lol:

But, when it lands here, I will certainly remove it and put the 12v coil you suggest on it. Anytime I tempt fate I usually lose.

Thanks!

ince it starts & runs fine & has for a long time, I call messing with it, "tempting fate"!

 

[HarryVanderpool]

(quoted from post at 10:54:53 08/04/22) Being it is a series circuit it matters not where it is in the circuit, it preforms exactly the same function.

Yep! Current is equal throughout a series circuit.
8)

 

[Tim PloughNman Daley]

I hate when that happens - adding non-essential parts to the circuit. Listen to Bruce (VA). Your coil is probably already a 12V unit. The OEM FORD BALLAST RESISTOR p/n
9N-12250 was ONLY used with the 39-50 Front Mount Distributor. Period. The later Angle Drive (Side) Mount Distributor did not use a Ballast Resistor. Period. You only
need to add an inline external 1-OHM Resistor to the coil circuit if it is a 6V unit. Avoid extra wires and parts dangling off simply by swapping out the 6V coil for a
12V coil. Whichever electrical system you are using, be certain you use a fan belt tensioning device on the GEN or ALT. Without proper fan belt tension, you will never
charge the battery.

FORD 8N TRACTOR OEM 6V WIRING DIAGRAMS:

FORD OEM BALLAST RESISTOR -USED ONLY WITH FRONT MOUNT DISTRIBUTOR:

HELP: The LH resistor Terminal Post connects to the COIL Stud Terminal Post as you face the back off dash. OEM Wiring is RED.

FORD 8N TRACTOR EARLY OEM DASH PANEL WIRING, RESTORED:

FORD WIRING JUNCTION BLOCK, AFTER 8N 263844 w/ANGLE DRIVE DISTRIBUTOR:

*NOTE: THIS IS NOT A RESISTOR.

8N TRACTOR 12V CONVERSIONS:

*ADD 1-OHM EXTERNAL RESISTOR IF USING A 6V COIL.

Tim Daley(MI)