Variable Valve Timing

VTEC system is used on the 2.2L engine. The system utilizes 3 different intake cam lobes and rocker arms. At low speed, the primary and secondary intake valves are operated by their own separate cam lobes. The connecting (middle) rocker is operated by the high speed cam lobe at all times. At low speed, the connecting rocker arm is not connected to primary or secondary rocker arms or valves and has no effect on engine operation.

Valve timing change will occur when engine speed is 4900 RPM or more, vehicle speed is 19 MPH or more, engine coolant temperature is 140°F (60°C) or more and with appropriate engine load (based on intake manifold pressure). When conditions are met (as determined by PCM), oil pressure is applied (through spool valve) to synchronizing pistons located in primary and connecting rocker arms. This locks primary, connecting (middle) and secondary rocker arms together so they are driven as a single unit by the higher lift and duration cam that operates the connecting (middle) rocker arm.