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Discussion Topic:
ignition resistor purpose
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MICHV8 |
06-01-2016 @ 5:07 AM
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Member
Posts: 446
Joined: Jul 2010
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My 39 under dash firewall is missing the ignition resistor...if I start it with a coil that does not contain an internal resistor, what are the ramifications? Thanks!
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kubes40 |
06-01-2016 @ 5:28 AM
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Senior
Posts: 3406
Joined: Oct 2009
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With a constant full 6 volts going to the coil, the longevity of the coil will be severely diminished. I am hoping TomO can jump in here and explain in detail "why" that is. He seems to have a great knowledge of the electrical system's "how's and why's". Regardless, a full 6 volts will burn your coil out.
This message was edited by kubes40 on 6-1-16 @ 8:55 AM
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TomO |
06-01-2016 @ 8:36 AM
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Senior
Posts: 7256
Joined: Oct 2009
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The ballast resister is used to limit the current in the primary circuit and to reduce the arcing of the points. If you run the car without one, your points will soon be so pitted that they will not work correctly and the excess current will cause the coil to run hot and short out. Are you missing both the resister and the circuit breaker for the lights? If so you have a fire hazard and it should be corrected ASAP.
Tom
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MICHV8 |
06-02-2016 @ 5:10 AM
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Member
Posts: 446
Joined: Jul 2010
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Thanks to both of you...I will correct the missing items
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MICHV8 |
06-02-2016 @ 5:11 AM
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Posts: 446
Joined: Jul 2010
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Is it only the modern "black tube" coils that have an internal resistor?
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TomO |
06-02-2016 @ 7:26 AM
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The tube coils that are the most commonly used are the 49-53 Ford and Mercury coils. These have an internal resister. The other stock Ford coils do not have an internal resister. Other tube coils may or may not have a resister.
Tom
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MICHV8 |
06-03-2016 @ 4:55 AM
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Member
Posts: 446
Joined: Jul 2010
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Tom() I'm guessing there is no simple way to determine if a coil has an internal resistor? If an internal resistor coil is used in tandem with the under dash resistor, the result is too low of a primary circuit? Thanks for the info...
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TomO |
06-03-2016 @ 7:40 AM
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Senior
Posts: 7256
Joined: Oct 2009
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An internal coil resister will measure between 1 ohm and 1.2 ohms. This measurment must be taken across the primary of the coil with a high impedance Ohmmeter. 2 ballast resisters will reduce the coil efficiency. I am having a hard time understanding your problem. Are you using an original type coil with the helmet distributor or some other configuration?
Tom
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MICHV8 |
06-04-2016 @ 5:07 AM
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Member
Posts: 446
Joined: Jul 2010
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Yes, plan to use a 1GA-12024. I have added the under dash resistor
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cliftford |
06-04-2016 @ 4:03 PM
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Senior
Posts: 845
Joined: Jan 2014
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Often someone will remove or bypass the resister to make it easier to start. if your engine is hard to start with the resister, you can run a conductor from the starter side of the solenoid, through a diode, to the hot side of the coil. This gives you full voltage to the coil while cranking, and saves wear and tear on the starter.
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