coil voltage 40 f0rd

[lenmissy]

what voltage should be going to coil on 40 ford do you use a resister to cut voltage down len

 

[4dFord/SC]

Should be 3.5 - 4 volts. Use a ballast resistor with the stock coil. Modern cylindrical coils may or may not be internally resisted and should be so indicated on the coil itself.

 

[oldford2]

Use the Ford resistor.What happens is: when you hit the starter the coil will get 6 volts which is good for starting. Then the resistor warms and cuts it back to 3.5/4 volts. Measure this when the engine is running. If I am wrong, I hope someone will correct me. John

 

[rotorwrench]

The voltage has to be measured across the resistor otherwise a multi meter will read standard system voltage at the bat terminal on the coil. I think most post model A cars used a ballast right up to the 8BA in 48 for trucks, 49 for cars, when they changed back to a can type coil. The coils by then could take about anything a 35 amp 6-volt system could throw at it. If you are using a later can type coil with a 1 to 1.5 OHM primary resistance, you shouldn't have to worry about a ballast but you can run one if you want.