These M157 / M278 spark plugs are designed and manufactured for not only high power applications but also factory replacement. The factory plugs do not handle the M157’s high cylinder pressures very well and frequently result in misfire problems, even on unmodified vehicles.

The M157 / M278 spark plugs are also 1 step colder to help prevent pre-ignition in engines that are making more power than stock allowing you to further push the envelope of your vehicle.

Product Overview

A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark, while containing combustion pressure within the engine. A spark plug has a metal threaded shell, electrically isolated from a central electrode by a ceramic insulator. The central electrode, which may contain a resistor, is connected by a heavily insulated wire to the output terminal of an ignition coil or magneto. The spark plug's metal shell is screwed into the engine's cylinder head and thus electrically grounded. The central electrode protrudes through the porcelain insulator into the combustion chamber, forming one or more spark gaps between the inner end of the central electrode and usually one or more protuberances or structures attached to the inner end of the threaded shell and designated the side, earth, or ground electrode(s). M157/ M278 spark plugs are designed and manufactured for not only high power applications but also factory replacement. The factory plugs do not handle the M157's high cylinder pressures very well and frequently result in misfire problems, even on unmodified vehicles. The M157/ M278 spark plugs are also 1 step colder to help prevent pre-ignition in engines that are making more power than stock allowing you to further push the envelope of your vehicle.

* Important: Please be sure to check and set spark plug gap prior to installation.