Head assembly with rotating valves for an internal combustion engine

A cylinder head assembly for an internal combustion engine, comprising:

• a cylinder head defining a combustion chamber and having at least one opening communicating therewith;
• at least one port;
• at least one rotatable valve element disposed between the at least one opening and the at least one port;
• and
• at least one seal assembly disposed between the at least one rotatable valve element and the cylinder head, the seal assembly comprising a seal having a concave sealing face which conforms to a peripheral surface of the at least one valve element, a labyrinth seal disposed opposite the sealing face, and a resilient secondary seal disposed between the seal and the cylinder head, wherein the seal assembly comprises a seal defining the sealing face disposed inside a shoe which defines the labyrinth seal and wherein the seal includes an aperture and the shoe includes a tube in fluid communication with the aperture.