The Stovebolt Site Forums The Shop Area The Electrical Bay Internal Resister Coil vs. coil w/external resistor

I have a 52, 3100 with a '58 - 235 in it. I am installing a completely new wiring harness and changing everything to 12 volts. I'd like to install an internal resistor coil, but need to know the pros and cons since I don't know the pitfalls of either. Any help would be appreciated.

My ‘52 3100 with ‘59 235 has a non resistor coil with a resistor mounted on firewall and a starter switch that has a 12v side terminal, that supplies a full 12 volts to the coil when starting. Once running that circuit disconnects and ithe. Oil is now powered thru the resistor circuit which drops the voltage to about 9 volts, so you don’t burn out you points.

When the industry went to 12 volt systems, this is the way they were installed by the factory.

Bottom line is I get full voltage to help start the truck then reduced voltage to help save the points.

Thanks...maybe I will stay with the external resistor coil. Was just trying to declutter the firewall, but have read where the internal resistor coils can overheat.

There are plenty of places to mount a resistor other than the firewall. Just put it somewhere it will be in the airflow from the fan to keep it cool. I've seen resistors attached to the same bracket that holds the coil onto the side of the engine.
Jerry

That’s the way mine was, but was warned it was not a good idea having another heat source mounted in the coil.

Here is a [LINK] to where this was discussed in a previous post of mine. Read down a few post to see the discussion.

If under hood components were actually as fragile as some of our discussions suggest, we'd be spending a lot more time on the side of the road with the hood up than we do. At normal highway speed, a coil fires something like 6,000 times a minute, the points operate at the same speed, and so do a bunch of other parts, mechanical and electronic.
Jerry