Variable Cam Timing Unit Assembly

Variable Cam Timing (VCT) unit assembly is coupled to camshaft through a helical spline in the VCT unit chamber. When flow of oil is shifted from one side of the chamber to the other, differential change in oil pressure forces piston to move linearly along the axis of the camshaft. This linear motion is translated into rotational camshaft motion through the helical spline coupling. A spring installed in the chamber is designed to hold camshaft in minimum overlap position (5 degrees) when oil pressure is too low to maintain adequate position control. Camshaft is allowed to rotate up to 30 degrees.