So then are there + ground and - ground coils I wonder? Could a larger capacitance condenser absorb the additional back EMF and compensate?
Unless you're dealing with an integral-coil distributor like the old banjo-housing Ford distributors with the coil mounted directly on top, just reverse the primary leads on the coil when changing polarity. The problem is caused by the secondary winding being connected to the wrong end of the primary which causes a reverse EMF being generated as the secondary current looks for a ground. The secondary actually uses the battery and the primary wiring, ignition switch, etc. as a path for the high voltage to find its way back to the end of the circuit. If the coil is labeled "ign" and "dist" at the primary terminals, just connect them backwards to the labeling when reversing the polarity. (+) and (-) labeled coil primary terminals are connected with the ground polarity toward the distributor.
Jerry
