The ballast resistor will drop the voltage to the coil primary whenever the points are closed and the ignition switch is turned on. When the points are open, you'll see full battery voltage on both sides of the resistor. It's normal to see about 9 volts at the coil with the engine running, down from about 13.5-14 V. at the battery terminals. 6 volts at the coil with the engine not running, points closed is about right.
What type of starter setup do you have, key start or stomper? The 12 volt stomp starter switch will have a small terminal on the side that needs a wire attached from it to the downstream side of the resistor, or the coil (+) terminal. That wire provides full battery voltage to the coil during cranking, bypassing the resistor. If the voltage to the resistor drops during cranking because of the extra load of the starter, voltage to the coil might not be sufficient to provide a good spark without the bypass.
The solenoid-operated starter for the key start system will have a small terminal on the solenoid cover labeled "I" (ignition). This terminal does the same thing as the bypass terminal on the stomp switch, providing full battery voltage to the coil during cranking.
Jerry
Edit: Is it possible that the wire from the coil to the distributor is getting grounded to the distributor housing? Turn the engine until the points are open, or just place a piece of paper or a business card between the points. The voltage at the (-) terminal of the coil, or the connector on the side of the distributor should go to battery voltage. If it stays near zero, you've got a grounded primary wire in the distributor, doing the same thing as the points staying closed all the time- - - -no spark.
Jerry
Last edited by Hotrod Lincoln; 01/24/2011 5:18 AM.
