Ignition Coil Question

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Tyler

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Working at night replacing various ignition components, I mistakenly hooked up the new coil backwards (it arrived from W&N already mounted in the new bracket, but clocked 180 degrees). Luckily my coupe didn't take off in reverse - actually, it seemed to run ok for the 20 minutes until I spotted the error. I corrected the wiring and it still runs ok. My question for the group: is my new coil permanently damaged?
 
I installed a Bosch Red coil in conjunction with Pertronix and a Bosch 008 distributor. Incredible increase in spark.

The red coil does require an external ballast resistor, so make sure that you purchase it with the coil.
 
reversed coil

I can't imagine there being any damage to the coil re: reversed leads. Just current going through a "coil" to increase voltage. I believe if connected for extended periods like that the wear on the points surface (from pitting) will be increased, but for such a short period you should be definitely good to go.

And yes, make sure you have that ballast resistor, otherwise you WILL burn up the coil in short order
 
texcarguy had written: "make sure you have that ballast resistor..."

Hmmm, I'm not sure sure - I think it depends on the type of coil.

My understanding is that the Bosch blue coil does not require a resistor. It's either built-in, or the primary windings have sufficient resistance to work OK without a resistor. I think 3 ohms is the necessary coil resistance to work without additional external resistance.

I'm not an expert on this, check my numbers, check the resistance of your coil, yadda yadda. But I will say that I have several cars that have run thousands of miles with Bosch blue coils just wired directly to the ignition switch, both with points and with Pertronix.
 
ballast resistance

Jay,

You're absolutely correct. As another contributor mentioned earlier, it does depend on the type of coil. Some do have the resistance built in. My understanding is that this is necessary for those times at idle or even when ignition is on but engine is not running... without some resistance in the system, the voltage will eventually burn the coil up.

Phil
 
re connecting the Coil

Running the coil as you did with reversed polarity was/is a common mistake that might impair engine performance but I can's see any direct impact on the coil itself. As memory serves me, many of the older British marques favored positive earth systems. Depending upon the type of coil, if it were run without a ballast resistor, that could cause the coil to prematurely cook. You did not state the latter situation occurred. I suspect unless you overheat the coil or drop it, it may live on for a long shocking life.
 
Coils...

Blue coil = no external resistor

Red Coil = use external resistor

But I have also read, from persons whose opinions I listen to, that the red (or blue) does not in fact deliver more energy to the spark plug. Also that energy is difficult to measure... it's not just the voltage that you want. Increased voltage will jump a larger distance, or fire more readily in a situation (compression, lambda condition, etc) that will inhibit a lesser voltage, but it's the delivered energy that's important... unless your compression chamber situation is modified in ways not above specified.

Hmmmm
 
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