A valve arrangement for controlling the flow of gasses through a cylinder of an Internal combustion engine, which includes an inlet shaft having an inlet flow channel defined therein, an outlet shaft having an outlet flow channel defined therein, the inlet and outlet shafts being mounted rotatabiy about an inlet and outlet port of the cylinder respectively, wherein the flow of gasses through the cylinder Is controlled as the shafts are rotated between a first position wherein the flow channels are In register with the cylinder ports, thereby allowing the flow of gasses through the cylinder, and a second position wherein the flow channels are dereglstered relative the cylinder ports, so as to inhibit the flow of gasses through the said cylinder.