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IGNITION COILSProduct information
Ignition Coil Types & Part Numbering System
The NGK Ignition Coil range offers the right coil for the majority of vehicles in Australia. These ignition coils are divided into six categories. NGK’s clever part numbering system reveals much about the type and quantity of ignition coils and ignition leads a vehicle may require.
Each part number is comprised of the following:
- U = NGK ignition coil
- 1 = Category
- 000 = Consecutive number
An NGK ignition coil in category U1 is almost always for vehicles with a mechanical ignition distributor and it supplies the spark plugs with high voltage via the distributor. An important note when servicing this type of vehicle, the number of ignition leads required corresponds to the number of spark plugs. Additionally an ignition lead from the coil to the distributor is required.
The U2 category coding describes a block coil with multiple high voltage outputs. This coil design supplies multiple spark plugs at once. Depending on the vehicle, one or more of these ignition coils would be required – typically one coil is required per cylinder head. The number of ignition leads corresponds to the number of spark plugs.
The U3 category coding includes a block coil with two high voltage outputs. One coil supplies two spark plugs simultaneously with one pulse of energy. Depending on the vehicle application, several of these ignition coils are required for one vehicle. The number of ignition leads corresponds to the number of spark plugs.
The NGK ignition coil in category U4, is a pencil coil with dual spark technology, as such the coil produces two spark plugs with high voltage. Commonly known as a coil stick or coil-on-plug, this ignition coil is attached directly on to one spark plug and one ignition lead is then required per coil, to connect to the remaining spark plug.
Ignition coils in category U5, have grown in popularity to become the most applied ignition coil design by vehicle manufacturers. This pencil coil type only ever supplies one spark plug with high voltage, as it is attached directly on to one spark plug. This ignition coil is also commonly known as a coil stick or coil-on-plug. No ignition leads are required.
The NGK range also includes ignition coil systems, identified by the U6 category. These are cylinder specific ignition coils in a complete system, so that a group of spark plugs are supplied with high voltage for the same component. In some cases more than one coil system is required per vehicle, i.e. a V6 configuration. This coil design generally does not require ignition leads.