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Rewiring the coil

Posted: Sun Sep 25, 2005 12:38 am
by walker
I am in the middle of rewiring the Rangie. It has an aftermarket coil and also a Lumenition system on the distributor.

Someone told me that I needed to add a resistor inline with the power to the coil. When I pulled out the old wiring I did not notice a resistor or any special resistor wire.

I spoke to the auto electrician and he thought the reisistor was only to stop the points burning out and if I did not have points (which I dont) then I should not need it..but.. Iwas told by someone else that if I don't add the resistor I will burn out the coil.

Anyone know the answer?

BTW it does say on the coil "use external resistor".

Posted: Sun Sep 25, 2005 4:50 pm
by RangingRover
There are two types of ignition coil, one type has an internal resistor, the other type, like you have, needs an external one. I believe (double check this though) that you use a ballast resistor (may be something slightly different though, ring a coil manufacturer to check). The reason is that the coil actually operates at less than 12 volts, except during starting. If you do not use a resistor on one which doesn't have an internal resistor, the coil will burn out in a relatively short amount of time.

*edit* quick bit of research - my 260Z has a Bosch GT40R coil in it, from God knows where (one of my mates donated it to the cause). It says on it "Use with resistor." No further info.
Quick look in the Bosch catalogue (http://apps.bosch.com.au/products/saa/i ... _coils.pdf) on the first page says "Coils which are for use with a ballast resistor have the letter R included in the part number."
Looks like use with resistor means a ballast resistor, can be found on most older cars at a junkyard.

Posted: Sun Sep 25, 2005 7:38 pm
by walker
Thanks,
I bought and installed a resistor today.