MG Car Repair: proper hookup of allison 700xr and what wires connect to which terminal on the coil, resistance ballast, ballast resistor

Question
i was given a mg midget.  it is not running, but we are getting close.  the wiring is a mass of spaghetti. can you tell me what wires go to which terminal on the coil, and what is a resistance ballast?  confused in ohio.

jim moore
kent, ohio

Answer
Hi Jim,
I can tell you about MGs but I have no experience with Allison so you would need to contact Allison about that.

A Ballast resistor is used with a coil that is not a 12 volt coil. Usually a 6v or 9v coil is used because when a starter is engaged, there is not 12v left available to operate a 12v coil. So they use a lower voltage coil and drop the voltage to that coil with a resistor called a Ballast Resistor. Then when the starter is engaged they bypass the resistor with another wire to run direct to the low voltage coil with the voltage left over when the starter is engaged and as soon as the starter is released, they run the current through the resistor to the 6v or 9v coil so as to not burn up the coil or the ignition system.

Some of the MG Midgets were designed that way but you didn't tell me what year your Midget was so I can't tell you if yours already has that system or not.
You need to contact someone who sells Allison ignition systems to get a diagram of their system connections. Then with that and if you will tell me what year midget you have I can tell you how the car is wired so you may be able to use the Allison system on it.
Howard