Abstract: A machine for cleaning an internal combustion engine cylinder head uses a high-pressure water jet supplied by a pump driven by an electric motor or an internal combustion engine powered by a power pack and via a spinning spray nozzle head mounted on a vertically reciprocating traveller travelling the length of a cylinder head clamped by headstock and tailstock clamping assemblies each with six conical-headed, spring-loaded clamping members clamped together by a pneumatic ram and rotatable horizontally at varying speeds by a variable-speed electric motor and drive assembly in synchronization with another electric motor driving the traveller; a spinning spray jet swivel head assembly is rotated via an hydraulic motor from the power pack; clamping and spray head assemblies are mounted within in a framed cabinet and a removable wheeled waste water collection tank underneath has fixed, vertically-opposed, horizontally spaced baffles for separation and settling sludge and floating scum from water which is then recy