• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Ballast Resistor Question

CrazyBoutRacin

Well-Known Member
Local time
6:00 PM
Joined
Sep 27, 2025
Messages
50
Reaction score
86
Location
Middle Tennessee
Need some help. Installing a rtr Firecore distributor on my 65 Coronet with a 440. Instructions say full 12 volts. So I can just connect all wires on both terminals of the ballast resistor with a jumper? There’s two wires on the output side and one is the coil positive, but I’m not sure where the other one goes to. Is there something else that needs the voltage decreased like the coil? Appreciate the help.
 
Are you running the coil that they say you have to run? Yes the wires need to be hooked together at the ballast for crank and run constant 12 volt distributor feed.
 
Need some help. Installing a rtr Firecore distributor on my 65 Coronet with a 440. Instructions say full 12 volts. So I can just connect all wires on both terminals of the ballast resistor with a jumper? There’s two wires on the output side and one is the coil positive, but I’m not sure where the other one goes to. Is there something else that needs the voltage decreased like the coil? Appreciate the help.
For a clean look, gut the ballast and solder in a piece of 12 gauge solid wire instead of the resister. It is easy to bypass the amp gauge on these models with a bolt in jumper at the bulkhead connector. Then add a voltmeter.
Mike
IMG_2082.JPG
 
Yes, I got the coil they recommended. It’s the newer square type. What I was wondering was about that second wire on the output side. I guess it’s sending the reduced voltage to something other than the coil. I can’t figure out what that would be.
 
Yes, I got the coil they recommended. It’s the newer square type. What I was wondering was about that second wire on the output side. I guess it’s sending the reduced voltage to something other than the coil. I can’t figure out what that would be.
Brown? It sends 12 volts to the coil-just during cranking and it is necessary, so either connect al 3 or do the concealed bypass.
Mike
 
For a clean look, gut the ballast and solder in a piece of 12 gauge solid wire instead of the resister. It is easy to bypass the amp gauge on these models with a bolt in jumper at the bulkhead connector. Then add a voltmeter.
Mike
View attachment 1995571
Is the bolt in jumper something you make or buy? I intend to have the amp gauge converted to volts.
 
Yes, I got the coil they recommended. It’s the newer square type. What I was wondering was about that second wire on the output side. I guess it’s sending the reduced voltage to something other than the coil. I can’t figure out what that would be.
Can you post their instructions
 
Brown? It sends 12 volts to the coil-just during cranking and it is necessary, so either connect al 3 or do the concealed bypass.
Mike
Yeah I traced down the one that feeds the coil (pos). There’s one more seems like it’s blue, same gauge as the other. What else needs the voltage reduced other than a ignition coil?
 
Yeah I traced down the one that feeds the coil (pos). There’s one more seems like it’s blue, same gauge as the other. What else needs the voltage reduced other than a ignition coil?
You do not want reduced voltage, full 12 volts to dizzy and coil.
 
Can you post their instructions
They don’t have any on the website for me to link. It stated it needs a full 12v and just find a power source, use 14 ga. wire and fuse at 15 amps. That I get, but this other wire besides the pos coil feed worries me. I hate to send 12v somewhere that needs it reduced.
 
They don’t have any on the website for me to link. It stated it needs a full 12v and just find a power source, use 14 ga. wire and fuse at 15 amps. That I get, but this other wire besides the pos coil feed worries me. I hate to send 12v somewhere that needs it reduced.
Nothing else needs reduced voltage. Did you not get instructions with it?
 
Nothing else needs reduced voltage. Did you not get instructions with it?
Yes I did. They are 10 miles away in my shop. Pretty straightforward. Just really basic distributor installation instructions. I can’t think of anything else that needs it reduced either. This all appears to be factory connections. Hate to send 12v somewhere it’s not supposed to be.
 
Yes I did. They are 10 miles away in my shop. Pretty straightforward. Just really basic distributor installation instructions. I can’t think of anything else that needs it reduced either. This all appears to be factory connections. Hate to send 12v somewhere it’s not supposed to be.
You bypass the resistor. The factory 12 volt feed stays at the coil. Your new wires go to coil positive, negative, and one to a engine ground point. If there is another wire it most likely will be your tach feed.
 
You bypass the resistor. The factory 12 volt feed stays at the coil. Your new wires go to coil positive, negative, and one to an engine ground point. If there is another wire it most likely will be your tach feed.
This is on the ballast resistor itself, not the distributor. I have to supply 12v to the coil positive. Three on the input side, two on the output side, of which one is the coil positive. The other I can’t figure out. I hate to throw 12v on it and hope for the best.
 
This is on the ballast resistor itself, not the distributor. I have to supply 12v to the coil positive. Three on the input side, two on the output side, of which one is the coil positive. The other I can’t figure out. I hate to throw 12v on it and hope for the best.
Just hook them together you are bypassing the ballast. You are making a mountain out of a molehill.
 
The second wire you are talking about is the 12 volt feed to the coil during starting. After it starts power is shut off to that second wire, and the coil receives voltage through the resistor from the blue wire.
 
This is on the ballast resistor itself, not the distributor. I have to supply 12v to the coil positive. Three on the input side, two on the output side, of which one is the coil positive. The other I can’t figure out. I hate to throw 12v on it and hope for the best.
Does post #6 answer your question?
Mike
Got that, but there’s another wire on that terminal. Trying to figure out where it goes and what it does that needs the voltage reduced.
There is another set of contacts in the ignition switch that provides 12 volts -bypassing the ballast-to give a hotter spark for starting. It uses a brown colored wire.
Mike
 
Back
Top