The metal bracket that my coil sits in is not grounded. I need to take a wire from this bracket to chassis ground. What gauge wire does this ground wire have to be? Thanks...
The ground (case) for the coil is only tied to the secondary winding (spark) side, so a 16 or 18ga wire would be fine. The majority of the resistance in the secondary circuit is the plug wires and plugs themselves, so you don't need a very large conductor (high voltage/low current).