Originally Posted by Bob2
Maybe I asked the question wrong! I have a Dodge 251 CI flathead engine on test stand, I would like to start and run the engine prior to installation in truck as it is a bear to install when you are working alone. I would appreciate it if someone could tell me how to wire it temporarly to run.
All the ignition needs is a hot wire connected to the positive side of the coil (if a negative ground, opposite if positive ground) going to a charged battery. If the test stand has a switch, use it, otherwise removing the jumper (hot wire) will shut the engine off. Do not leave the wire attached to the battery and coil unless you are starting or running the engine.
Points ignition systems sometimes use a ballast resistor or resistor wire to lower the current to the coil once the engine is running. This allows the engine to start using full battery voltage for easier starts but lowers the voltage while running to extend the life of the ignition once running. If you need a resistor in the circuit, this can be accomplished by wiring a circuit that uses a ballast, w/a toggle switch to select between "Start" (no ballast) and "Run" (w/ballast). If the engine isn't going to be run for long, as long as the coil temperature is watched closely for overheating, you can run w/o a ballast or resistor wire, etc.
The starter can be actuated by using a heavy jumper between the battery cable and the "Start" terminal of the starter solenoid. If the test stand has no solenoid, jump between the battery and the starter terminal.
A wiring diagram for a '47 MOPAR: