A cylinder head assembly includes a cylinder head having an igniter mount that forms a portion of a fireside surface of the cylinder head. The assembly further includes a sleeve abutting the igniter mount within an igniter bore in the cylinder head, such that the sleeve and the cylinder head together form an igniter cooling passage circumferential of the igniter mount, and extending axially between the sleeve and the cylinder head. The configuration of the igniter mount and sleeve improves heat dissipation and reduces likelihood of pre-ignition in an internal combustion engine.