Abstract: A valve positioning tool for supporting valves in proximity to valve seats within a cylinder head and piston sleeve assembly for an overhead valve, internal combustion engine. The valve positioning tool has a frame with pivotally attached, biased clamping devices for engaging the flange of the cylinder assembly, to restrain the movement thereof. The valve positioning tool also includes a positioning device for communicating with and locating the valves within the cylinder assembly. An extending device is attached to the frame and to the positioning device for axially extending the positioning device within the cylinder assembly. The detachable surfaces of the positioning device are adapted to deform when in contact with the valves and the internal surfaces of the cylinder assembly.