Abstract

A VCT phaser for an engine having a housing, rotor and a spool valve. The rotor having a bore comprising an open outer end, an inner surface, and inner end having a vent port and arranged along the bore, an advance port, a common port, a retard port, and a lock port. The spool valve comprises a spool with a first land, a first groove, a second land, a second groove, and a third land, with the area between the inner surface of the bore and the first groove defining a first chamber, the area between the bore and the second groove defining a second chamber, and the area between the bore and the inner end of the spool defining a third chamber. A passage between the first groove and the second groove for fluid passage provides fluid communication between the first chamber and the second chamber and lock pin.