Spark Plugs Information
Spark plugs are used in engine cylinders to ignite the fuel in an internal combustion engine while withstanding high pressures and temperatures. Spark plugs use high voltage to jump a spark between two electrodes that have a gap between them. The spark provides the energy required to ignite the air fuel mixture in the combustion chamber of an internal combustion engine.
There are many things that differ between different kinds of plugs. One is the gap between the electrodes. Also, different plugs have different heat ranges which will be needed based on the air fuel ratio and compression of the engine.
The electrode material will vary on different plugs. The most common materials are copper, platinum, and iridium.
The different materials yield different performance and longevity properties. Copper typically has the best spark properties but wears out the quickest. Platinum has the least desirable spark properties but lasts the longest. Iridium's properties fall in between copper and platinum's performance and longevity properties.
AD 54-04-01 - Spark plugs/AC spark plug of General Motors Corp
BS ISO 28741 - Road vehicles - Spark plugs and their cylinder head housings - Basic characteristics and dimensions