Multi-ground plug
Traditional ground
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Some engine designs require that the spark plugs have the ground electrode placed to the side of the center electrode rather than below as on a traditional plug (see photo). This may be for combustion chamber design as in the case of a rotary engine, or a surface gap design as used in leaner air/fuel ratio’s on industrial engines. The side electrode design tends to erode the tip of the ground electrode faster than a traditional plug. Erosion at these points creates a larger gap between the center and ground electrodes, causing plug misfire. Thus, if the engine design requires a side discharge plug, you add more ground electrodes to extend plug life. It is important to note that multi-ground does not mean multi-spark, there will still only be one spark at a time. |
