The oil pump (36) supplies lubricant to the engine (E) as well as to the camshaft system. This includes the valve timing control (31). A first solenoid valve (34) regulates the oil flow to and from the valve timing control and to the lubrication system (20) for the moving parts of the camshaft. At high engine speeds a second solenoid valve (41) connects the oil supply to a second lubrication system (21), to ensure that the camshaft has sufficient lubrication. The second lubrication system is supplied via a flow restriction (42). An engine speed sensor (S) is connected to the controller (ECU) to disconnect the second lubrication system at low engine speeds, enabling the whole of the oil supply to be applied to the timing control unit and to the main lubrication system.
