Cylinder head for rotary valve internal combustion engine

A method of manufacturing a cylinder head for an axial flow rotary valve engine, said head comprising a bore having an axis and adapted to house an axial flow rotary valve, a window in said bore through which at least one port in said valve periodically communicates with a combustion chamber as said valve rotates, at least two axially extending slots in said bore, adjacent opposite sides of said window, each said slot being adapted to locate a floating elongate gas sealing element, and at least one spark plug hole adjacent to said bore and adapted for mounting a spark plug associated with said valve, characterised in that said cylinder head is manufactured from a casting and said method comprises machining at least one elongate axially extending cooling passage in said head, said passage being disposed between said bore and said spark plug hole, adjacent to one of said slots, said passage having a substantially constant cross section and extending axially at least over the length of said slots.

An axial flow rotary valve engine comprising at least one cylinder, a cylinder head, an axial flow rotary valve associated with each cylinder rotatable within a bore in said cylinder head about an axis, said axial flow rotary valve having an inlet port and an exhaust port periodically communicating with a combustion chamber through a window in said bore as said valve rotates, at least two axially extending slots in said bore, adjacent opposite sides of said window, each said slot housing a floating elongate gas sealing element, and at least one spark plug associated with said valve, each spark plug being mounted in a corresponding spark plug hole adjacent to said bore, characterised in that said head further comprises at least one elongate axially extending cooling passage disposed between said bore and said spark plug hole, adjacent to one of said slots, said passage having a substantially constant cross section and extending axially at least over the length of said slots, one end of said passage communicating with a high pressure cooling channel and the other end communicating with a low pressure cooling channel.