I am looking to replace the Dizzy in my Bug with a replacement unit with Electronic ignition already built in.
At the moment though I have a ballasted coil on my Bug (Running standard points)
Would I need to replace this with a new non Ballasted coil or will the new unit work OK with the Ballasted Coil...?
Would there be any issues in replacing a Ballasted Coil with a Non Ballasted...?
In days of yore before electronics had been discovered, the function of the ballast resistor was to reduce the voltage supplied to the ignition coil primary coil to 9V. At 9V supply, the (ballasted, 2 input connections) coil delivered a secondary voltage to the points and thence to the spark plugs sufficient to run the engine under normal (ie running temperature) conditions. But what about COLD conditions - as at start-up? Enter the ignition switch. In starting, this fed 12v to the coil primary BYPASSING the ballast resistor, and hence delivering around 1/3 more voltage to the primary. This then generated around 1/3 higher voltage in the secondary coil, thus delivering a 1/3 higher voltage to the spark plugs, to facilitate cold starting.
In a modern electronic ignition, the circuitry in the ignition module takes care of this function, and indeed generally offers a more complex voltage and timing profile according to what it sees the engine doing in terms of rpm and trend (eg cold start, rpm rising, rpm slowing etc) so the ballast resistor can be consigned to the museum, along with the points, condenser and all their mechancal problems.