Currently wiring a 48 merc pickup, all stock drivetrain, I want to know how the coil is wired for power during cranking. Small block chev's have a terminal on the starter, but not flathead fords. Thanks guys.
6 volts don't have hot starts. My 56 12 volt Ford is done on the start part of the ignition switch and when in the "on" key switch it goes to the ballast resistor for normal running.
If you use a starter relay, like they used in Fords with 12v systems, it has an R terminal. If it's a floor switch, I don't know if they make them like that or not... But it should start ok without the bypass wire.
Well I'm thinking it should start without the bypass wire, got a 12 volt coil, do you think I need a ballast resistor as well?
The unique truth about ignition coils is that almost all are 6 volts. That is the reason for the resistance and the bypass during starting. The 12 volts during starting give a fatter spark, and the 6 volts during running allow the points and coil to last longer. There are a few intended for 12 volt operation, and are usually marked as having an internal resistor. The internal resistance simply takes the place of the MoPar-style ballast resistor, allowing you to wire W/O external resistor. Cosmo
Check the resistance of the primary on your coil (between the + and - terminals). One ohm to 2.5 ohms, you need a ballast resistor. 2.5 to 3 ohms, you might need one. 3 ohms or more, no ballast resistor needed. This is for 'standard' ignitions (points or basic electronic units). If running an electronic ignition with current limiting or dwell control, no ballast resistor needed.
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