in the conventional mounting arrangement of these two components shown in fig5 and 6 the spark igniter electrode assembly 106 is mounted first with the mounting flange 116 directly against the outer surface of the wall 202 of the combustion chamber 200 the thermistor assembly 110 is then mounted on top of the spark igniter electrode assembly 106 using the same fastening element or screw 108 for attachment when mounted the ceramic insulator 112 of the spark igniter electrode assembly 106 extends into the chamber 200 see fig1 and 15 using the through hole 104 to generate the vent in accordance with the present invention may be accomplished in at least two different ways according to a second embodiment of the present invention the vent is formed by reversing the mounting order of the spark igniter electrode assembly 106 and the thermistor assembly 110 as shown in fig7 hence the thermistor assembly 110 is mounted to the combustion chamber wall first and then the spark igniter electrode assembly 106 is mounted on top of the thermistor assembly mounting flange 114 with both components again sharing the same screw 108 for attachment however unlike in the conventional assembly orientation in the assembly orientation according to the present invention the thermistor assembly mounting flange 114 creates a gap generally designated by reference numeral 115 between the mounting flange 116 of the spark igniter electrode assembly 106 and the outer wall 202 of the combustion chamber 200 this gap 115 in combination with the annular area 280 see fig1 provided by the clearance between the inner diameter of the through hole.