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Old 07-01-2019, 05:52 PM   #4
Synchro909
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Location: Melbourne, Australia
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Default Re: Cause of hot ignition coil?

Quote:
Originally Posted by rotorwrench View Post
The 3-Ohm coil should be able to take the heat. Later types like that are usually insulated with an epoxy resin that is designed to work at the higher temperatures. As was mentioned previously, the 1.5 would need the ballast of 1.3 to 1-5-Ohm. This splits the heat between the resistor and the coil. It makes the older type coils a lot more reliable otherwise they will burn up in a short time. The 1.5-Ohm coils will work on a 6-volt system with no ballast at all.
I believe the 1.5 ohm coils are for 6 volt installations. Put them on 12 volts and you draw twice the current and produce 4 times the heat. IMO, there's your answer.
I suspect the coils that overheated will be labelled 6 v (if they're labeled at all) and the 3 ohm one labelled 12 v.
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