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Old 08-31-2020, 11:42 AM   #11
rotorwrench
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Join Date: Jun 2010
Location: San Antonio, Texas
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Default Re: over heated coil

One way to deal with it is to use an external ballast resistor. If they run too hot then they are drawing too much current. The ballast will bleed that off and keep the heat out of the coil. Ignition coils usually only fry themselves if the key is accidentally left on too long. A coil will always be pretty warm to the touch but it shouldn't be so hot as to burn you if you touch it.

Many manufacturers started using ballast resistors when the change to 12-volts came about in 1956. The 1.5-ohm primary type coil works well with a 1.3 to 1.5-ohm ballast. In later years, the epoxy resin insulation inside the coils allowed for a full 3-ohm primary resistance inside the coil. This eliminated the need for an external ballast for 12-volt systems.
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