How to test ignition coil

[GregY]

I think the coil might have gone bad on my '71 440. I know there is a procedure for testing the coil where you measure the resistance between the center post and the + and - terminals and compare those with acceptable values (or something like that). Does anyone know the details of this method? It is a high performance Accel coil if that makes any difference. Thanks.

[Dr. Righteous]

Well a "hot spark" from an igintion system is a blue color when you see it arc. If the car does run disconnect one of the plug wires and leave the end near metal ground. You should see a bright blue arc when that cylinder fires. If the spark is redish in color that is a weak spark.
A good/bad test of a coil is to ground the negative side and momentarly touch 12v to the plus side of the coil. If a spark jumps out of the iginition terminal and shock the crap out of you the coil is 'working'. How "hot" (correct amount of high voltage) is the running test above.

Pretty basic, nothing too high tech.