Spark plug

In a spark plug having a shell and an insulator seated in said shell and sealed therein against the passage of combustion gases, said insulator having a stepped central bore, an improved center electrode assembly mounted in said insulator bore comprising a lower center electrode element seated in said bore, said electrode element having first end means for defining one side of a main spark gap exterior to said bore and second end means defining one side of an auxiliary spark gap within said bore, an electrically conductive ball seated on a step in said bore, said ball being spaced from said second end means for defining a second side of such auxialy spark gap, an ignition noise suppressor positioned within said bore, a terminal, and springs means electrically connecting said ball, said suppressor and said terminal in series.