Ford CMP Coil Bracket

[T Creighton]

Originally Posted by david moore

Lynn has answered another question that I had - why, when I switch on the ignition with the coil resistor in circuit does the latter get hot? I did notice that input to the resistor was 6.9V and output 4.9V which I thought was bad news until Lynn 's message said that's how it should be. Presumably not a good idea to leave the switch on without the engine running - though it should still get hot even them, shouldnt it? Same voltage and resistance? The mysteries of electrics!

David, Lynn or others may contradict me on this but as I understand it the wire type resistors heat up due to the current trying to overcome the resistance. As they heat up the resistance increases and voltage decreases until a balance is reached when 6v is reduced to 4v. Therefore more voltage is available for starting as the resistor is cold and passes nearly all the 6v as long as the key has not been left on for a while first and the points happen to be closed.
Some vehicles have a starting circuit which bypasses the resistor when the starter is engaged.
Some say put a cold wet rag on the carb or fuel line when a hot vehicle will not start. Maybe it should be put on the resistor and coil instead!!!
Regards, Terry