Lucas 12v Ignition Coil

Lucas Blue 12v Ignition Coil

Lucas 12v Ignition Coil

A non-ballasted coil for systems without voltage increase for starting. This coil provides more starting power than standard energy ignition coils. This ensures smooth engine running and good starting performance. For engines up to 6 cylinders
IGNITION COILS
Ballast and Non-Ballast Ignition Systems

Contact breaker (points) type ignition systems, as fitted to most Ford models up to around 1980 (although it lasted up to 1987 for the Capri), can have either a ballast fitted in the wiring loom or not.
What is a ballast?

Quite simply, it is a resistor that has the purpose of reducing the voltage to the coil.
Why do some ignition systems have a ballast fitted where others do not?

Originally, all ignition systems did not have a ballast fitted which meant that the ignition system used a 12v coil with a 12v feed from the battery via the ignition switch. Such a system works fine when an engine is running, but problems can occur when starting the engine. The starter motor draws a huge current from the battery leaving less energy to create a spark across the spark plugs. The result is a weaker than normal spark which is not ideal for starting an engine. This problem is worsened by colder temperatures and/or a worn starter motor which will draw even more energy for starting and leave even less energy for sparking. To overcome such a problem, ignition systems were changed to run a lower voltage coil (usually 9v), and these coils could still give the same output as the original 12v coils.

In order to run such a coil, the 12v ignition feed runs through a ballast, reducing it to 9v at the coil.

To assist starting, a 12v feed (usually from the starter) bypasses the 9v ignition feed, giving the 9v coil a 12v feed. The result is a better than normal spark which is ideal for starting, particularly on cold damp mornings. As soon as the engine has started, the 12v feed is cut and the coil will run on the 9v ignition feed.