Abstract: A two-piece igniter includes an outer housing that includes a cylindrical member having an outer wall and an inner wall that defines a passage through the outer housing. The igniter further includes a plug member adapted to fit within the passage of the outer housing and that includes an axial electrode and an axially insulating insulator element encircling the axial electrode, the axial electrode having a first end for connection to an electric source and a second end for engagement within a combustion area. The igniter also includes a longitudinally extending biasing member positioned about the plug member. The plug member may be releasably coupled within the outer housing by inserting the plug member within the passage of the outer housing and by manipulating the plug member once inserted.

Abstract: A two-piece spark plug includes an electrically conductive outer housing including a cylindrical member having an outer wall and an inner wall, the inner wall defining a passage through the outer housing, and a plug member releasably coupled within the outer housing and including an axial electrode and an electrically insulating insulator element encircling the axial electrode, the axial electrode having a first end for connection to an electrical source and a second end for connection within a combustion chamber, and the insulator element having a circumferential first groove and adapted to be positioned within the passage of the outer housing such that a gas-tight seal is formed between the insulator element and the inner wall of the outer housing.

Abstract: An arrangement for easily and rapidly replacing a spark plug in a bore of a cylinder head includes a conductive cylindrical body that screws into the bore. It has a tapered internal passage that receives a replaceable plug with a tapered metal outer surface. A resilient sealing ring retained by the plug seals gas tight against the inner passage. An annular groove on the outer surface of the plug receives groove engaging elements or balls mounted in the body to lock the plug securely in position. A sliding locking sleeve surrounds the groove engaging elements and prevents the elements from moving out of the groove in a locked position. The sleeve may be manually reciprocated to an unlocked position in which the elements are free to move out of the groove so that the plug may be easily replaced. A spring biases the sleeve to the locked position.

Abstract: An arrangement for easily and rapidly replacing a spark plug in a bore of a cylinder head includes a conductive cylindrical body that screws into the bore. It has a tapered internal passage that receives a replaceable plug with a tapered metal outer surface. A resilient sealing ring retained by the plug seals gas tight against the inner passage. An annular groove on the outer surface of the plug receives groove engaging elements or balls mounted in the body to lock the plug securely in position. A sliding locking sleeve surrounds the groove engaging elements and prevents the elements from moving out of the groove in a locked position. The sleeve may be manually reciprocated to an unlocked position in which the elements are free to move out of the groove so that the plug may be easily replaced. A spring biases the sleeve to the locked position.