Ballast resistor mystery

[regularman]

I have been working with my 77 and getting the wiring all straightened out. Here is the mystery, and I think it most likely has to do with the electronic distributor(which mine does not have, its been changed to points type by PO).

Looking at electrical drawings from different sources, they are all wrong. They all show the white wire(ignition hot) going to a ballast resistor and then a white/light green going to the coil. I went through the entire loom and the light green goes from the solenoid to the coil(12v to coil on start) and then way down the wring harness to connect to a pink wire with a stripe(not on drawings).

Having a parts car as well I confirmed a few things. The white goes to a resistor of 10 ohms then to a white/blue wire and to the distributor connector. I'm thinking the ballast resistor shown in the drawings is not there. It shows another resistor going to the distributor and I am thinking that is the 10 ohm one and a wire coming out of the distributor feeds the coil.

I have confirmed the car has a 1.5 ohm coil and so does indeed need a ballast resistor of about the same resistance. The 10 ohm resistor(from either car) just won't get it. Wired in series with the coil in a conventional setup, it only gives the coil about 2 volts.
I am an electrical person and I plan on buying another ballast resistor and getting it working, but I have not found a good drawing to show how the original setup powered the coil.

 

[regularman]

Mystery solved. The green with light green stripe goes way out near the headlight wiring then connects to a pink with white stripe wire that goes all the way back right before going through the fire wall and connects to a white wire. The resistance of the pink/white wire is 1.5 ohms. There is not ballast resistor, they used a piece of wire to do the job. Would have been nice to put the pink/white in the wiring diagram and label it. All is good with the ignition circuit. The 10 ohm resistor is for the electronic distributor and not needed at all.

 

[dklawson]

Kim, several BMC/BL cars with ballast ignitions used the pink/white resistance wire instead of an external resistor. While the pink/white wire is original, they have a reputation for overheating inside the harness and damaging adjacent wiring.

A number of my acquaintances in the U.K. disconnect the pink/white wire and use an external ballast resistor instead. The quick fix they use is to run a white wire to the fuse box, connect the other end to the ballast resistor and run another wire from the other side of the resistor to coil (+). If they want to retain the ballast function, they leave the white/yellow wire connected from the starter solenoid to coil (+).