Ballast Resistor For Points And Coils.

[rigfire]

My recently aquired S75 fire truck has dual points and coils that are fried and cooked. Way to much heat. What is the cause? Wrong coil?

For a temporary fix, we wired a ballast resisitor in front of the one coil we replaced. Was a friends idea that seems to work.

Did stock wiring have a ballast resistor?

Donny

[truxnut]

Most all of the 12 volt systems I have seen made before '55 or so use internal resistor coils. A 12V coil that uses a external resistor will fry the points and sooner or later kill it's self also. You can either replace with internal resistor coils or use regular ones with external resistors.

[rigfire]

Most all of the 12 volt systems I have seen made before '55 or so use internal resistor coils. A 12V coil that uses a external resistor will fry the points and sooner or later kill it's self also. You can either replace with internal resistor coils or use regular ones with external resistors.

Thanks for the help. Sorry for the late reply. Have been swamped at work. For the time being we have wired a ballast resistor in from of one of the coils. I am trying to find out how Mack stock wiring was configured.

Donny

[DWaits]

Thanks for the help. Sorry for the late reply. Have been swamped at work. For the time being we have wired a ballast resistor in from of one of the coils. I am trying to find out how Mack stock wiring was configured.

Donny

Donny,

I have a wiring diagram for the standerd E series chassis, it does not show the dual coil/distributor set up but it might be of some help.

Let me know if you need a copy.

David

[rigfire]

David,

Thanks for the offer.

Address is P O Box 14

Midland, TX 79702

I will gladly pick up any costs.

Donny