ignition system
The purpose of an Otto-cycle "spark ignited" engine's ignition system is to ignite the fuel-air mixture in the cylinder at the correct moment. This is done by sending a high-voltage (on the order of 15,000-30,000 volts - don't touch that, it hurts, don't ask how I know that...) pulse of electricity across the spark plug gap, at the tip of the spark plug in the combustion chamber. The timing of this is very critical, and is controlled by the ECU. In Fenix's current setup, the main parts of the ignition system are the distributor, ECU, Capacitive Discharge Ignition (CDI) module, coil, plug wires, and spark plugs.
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This high-voltage pulse from the CDI runs through the ignition coil, which is a high-inductance transformer. The coil has two wire coils, the primary and secondary, one inside the other, the secondary having many times more turns than the primary. Current through the primary winding causes a magnetic field, and changes in this field, resulting from changes in the current (caused by voltage) induce a voltage in the windings of the secondary coil, resulting in a very high voltage – on the order of 15,000-30,000 volts. This voltage passes through a wire to the distributor cap, where the rotor directs it to the applicable post, from where it passes through another wire to a spark plug. Though a new distributor, I used the same distributor cap (an old brown Bakelite one I found in a junk bin at a swap meet) I'd previously used on the stock SVDA distributor, it fit the same and runs fine. The spark plug wires are carbon-core, thus their electrical resistance is fairly high – the high resistance suppresses electric fields, which can disrupt other electronics such as the ECU and radio. As they carry very high voltages and low currents, the resistance has minimal effect on spark energy.