420motorsport. Ignition Coils – Pencil Coils, Coil Packs & Canister Coils

Pencil coils, coil sets and canister coils

Many newer engines have one coil per cylinder, mounted directly on the spark plug. This type is called a pencil coil or COP (coil-on-plug). Examples include NGK COP Pencil Type for e.g. VW Touareg and Kia Sorento, as well as Bosch 14V Pencil Type 143. For other engines, complete sets are available, e.g. BLOX Honda K-Series Coil Pack Set of 4 or Ford Racing Hi-Energy Engine Ignition Coils for 5.0L/5.2L in sets of 8. Older engines with a distributor typically use a single canister coil, e.g. Edelbrock's 12V coil with 1.4 ohm primary resistance. Here the coil works together with the distributor and possibly an ignition module.

How to choose an ignition coil

Fitment: Check the OE number or engine, e.g. 036905715G/036905715H for the Bosch coil, and make sure the connector and length fit.

Primary resistance: On canister coils, the resistance must match the ignition system. The wrong value can cause a weak spark or put strain on the module.

Power goals: More boost or higher compression typically requires more ignition energy. However, the spark plugs and plug gap must suit the coil.

In addition to NGK, the category includes brands such as FAST, Mishimoto, Granatelli Motor Sports and aFe. You'll find other ignition parts under ignition components.

Installation and maintenance

Pencil coils can typically be installed without special tools. However, the rubber boot must sit fully down over the spark plug. First remove any oil or moisture from the spark plug well, as it can cause arcing or damage the boot. If the spark plugs are worn, it makes sense to replace them at the same time.

Frequently asked questions

Do I need to replace all ignition coils at once?

It's not necessary. A single faulty coil can be replaced on its own. However, if the coils are the same age and mileage, it can make sense to replace the whole set so the ignition is consistent across all cylinders.

How do I know if the ignition coil is faulty?

Typical signs are misfiring, rough idle, shaking under load and a fault code for a specific cylinder. Swap the coil with the one from the neighbouring cylinder. If the fault moves with it, the coil is probably the cause. Otherwise it may be the spark plug or the fuel injection.

Does a more powerful ignition coil require other changes?

It depends on the engine and the project. Spark plugs, plug gap, ignition leads and possibly the ignition module must suit the coil. On canister coils, the primary resistance must also match the system. Follow the manufacturer's instructions for the specific part number.