Type: 6431
14mm Thread, 12.7mm (1/2") Reach, 13/16" (20.6mm) Hex Size, Gasket Seat, Non-Resistor, Solid Terminal, Semi-Surface Discharge, Heat Range 8
Surface gap plugs are nearly immune to preignition, and usually require a special high energy ignition system, they can be susceptible to fouling especially in colder applications, may be necessary in high compression applications. In addition, NGK surface gap plugs have all the features of their traditional plugs including corrugated ribs, pure alumina silicate ceramic insulator for greater strength and better heat transfer, copper core and triple interior seal.