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Old 09-18-2010, 09:26 PM   #7
CWPASADENA
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Location: PASADENA, CA
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Default Re: Ignition resistor

Quote:
Originally Posted by gmc1941 View Post
Fords main reason for the resistor was to lengthen the life of the points by reducing the arc during the opening and closing of the points.
If you DO NOT use a resistor with a Early Ford V-8 "low voltage" Coil, you will burn the points as these coils will draw too many amps. These coils have lower primary resistance and were designed to run on reduced voltage.

You can run a 4-Cyl (Model A or B) Coil or any aftermarket "6-Volt" coil (that is designed to operate without a resistor) and you WILL NOT burn the points because these coils have higher primary resistance and were designed to run on full voltage. However, if you run a "full Voltage" coil, you will loose the hotter spark during cranking, "cold start" feature of the original Early Ford V-8 System. I.E., Starting on full battery voltage and running on reduced battery voltage.

The voltage that the coil "Sees" and the resistance of the primary windings is what determines the amount of the current thru the points. Increasing the voltage to a coil will raise the primary current. Increasing the resistance of the primary windings will reduce the current. Too much current thru the primary windings will cause the points to burn. This is why you use a resistor with a "reduced Voltage" Early V-8 Ford coil and you do not use a resistor with a "full Voltage" coil.

Chris
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