If you've ever seen a mechanic draw a tiny line on a spark plug before changing it, they're not performing witchcraft — they're indexing it. The idea is simple. Most standard types of spark plugs have ...

Spark plug indexing sometimes is necessary to avoid side-electrode contact with high-dome pistons. Moroso offers different thickness spark plug washer kits to do this. Some theorists claim positioning ...

If you consider your spark plugs little more than disposable engine parts to be replaced for every event or two, you're missing out on a valuable engine-tuning tool. Not only can the correct plug ...

Gas-powered internal combustion engines need spark plugs to (literally) ignite and complete the combustion stroke, enabling the motor to produce power. They may seem unusual to the untrained eye, but ...