A variable phase drive coupling is described for providing drive from an engine crankshaft to two sets of cams. The drive coupling comprising a drive member 12 connectable for rotation with the engine crankshaft and two driven members 18, 20 each connectable with a respective one of the two sets of cams. In the invention, the angular relationship of each of the driven members 18, 20 is independently variable relative to the drive member 12 under the action of camshaft torque reversals.