Ignition source adapted for positioning within a combustion chamber

An ignition source for initiating combustion is provided. The ignition source includes an electrical delivery conductor mounted in a delivery conductor mounting structure. An electrical ground conductor is mounted in a ground conductor mounting structure and extends from the ground conductor mounting structure to a point proximate the delivery conductor to define an ignition spark gap between the delivery conductor and the ground conductor. At least one of the delivery conductor and the ground conductor are mounted in a respective one of the delivery conductor mounting structure and the ground conductor mounting structure so as to be selectively positionable with respect to the other one of the delivery conductor and the ground conductor to selectively adjust a width of the ignition spark gap.