Ignition Coil ballast Resistor

[ModelA29]

Originally Posted by mark180

I’m looking for my ballast resistor. What do they look like?

If it's a 6V stock Model A you don't have one.
If it's been converted to 12V they generally look like this. Chevy and Chrysler seemed to use the external resistor and Ford had a resistance wire built into the harness

[mcgarrett]

If my information (and memory ) is correct regarding the Early V8 cars, the factory installed ignition resistor allowed the engine to start on 6 volts, but actually run on 4 volts. At least that's what one elderly V-8 sage told me.

[2speed]

An explanation of the Kettering system. Including the ballast resistor.


https://en.wikipedia.org/wiki/Delco_ignition_system

[rotorwrench]

Wire wound resistors heat up so fast that it wouldn't be of much help for starting. In the event of starter relays and solenoids, it became possible to route a full current charge through the start relay or solenoid systems but it would only function during the start cycle function. As soon as the starter switch is released then the power reverts back to the controlled ballast resistor or resistor wire in systems so equipped.

Ford didn't want to pay for the patent use of the Kettering system so Fords all used the timer and trembler coil system until the model A came out. By that time, the Kettering patent had run most of it's course.