NGK 6431 BU8H Surface Gap Spark Plug Surface gap plugs are nearly immune to pre-ignition, and usually require a special high energy ignition system. They can be susceptible to fouling, especially in colder applications, but may be necessary in high compression applications.
Trivalent metal plating provides superior anti-corrosion and anti-seizing properties
Corrugated ribs prevent flashover
Pure alumina silicate ceramic insulator, provides superior strength and better heat transfer
