How To: Spark plug polarity

[Mike K]

Originally Posted by Lynn Eades

Hanno, I have read that once a coil has been used the wrong way it gets used to it and when you change it over, its ouput can be significantly reduced.

I think that would be true if the coil has a iron core , the core will retain a little residual magnetism . But if you change the wires around to the correct polarity , the reversal of polarity will quickly re-energise the iron core to the correct polarity . In theory the output will not be reduced.


If you reverse the polarity of a auto generator, it's power output is not affected

My Land Rover has a + ground system . The coil has the terminals marked: CB (contact breaker) and IG ( ignition) only a blind person would connect the wires the wrong way around.