Gates variable valve timing spool valves control the flow of pressurized engine oil to the valve-control mechanism. Responding to engine-management commands, the valve directs oil through the appropriate passages so the valvetrain can change operating modes as driving conditions require. Reliable hydraulic control supports smooth engine operation and the intended balance of performance and fuel efficiency. Gates designs its replacement valve-control components around original-equipment fit and function, providing a dependable replacement for a worn or malfunctioning spool valve during valvetrain repair.