Spark plugs that haven't been changed for a long time can become one with the cylinder head. Fortunately, it's possible to repair damaged threads instead of scrapping the head. (Photograph by Chris ...

For the average stocker in good running condition, spark plug selection is a cinchchoose whatever brands on sale, look up the plug part number in the catalog, and go down the road. At the opposite ...

The spark plugs in a gasoline engine are not universal, one-size-fits-all components. Plugs are made of a variety of materials with different electrode setups and thread configurations, and knowing ...