VCT Actuator - Inlet Camshaft
| ITEM | DESCRIPTION |
|---|---|
| 1 | VCT actuator unit - inlet camshaft |
| 2 | Chamber - advance adjustment |
| 3 | Chamber - retard adjustment |
| 4 | Free play in locked home position 0.25 - 0.75 degrees |
| 5 | Maximum adjustment angle |
| 6 | Locking pin |
The inlet camshaft VCT actuator has four hydraulic chambers. The additional chamber when compared to the exhaust camshaft VCT actuator gives greater adjustment torque.
The four chambers allow hydraulic pressure to act on the central piston. The pressure is effectively directed into the four chambers and consequently applied to the four 'pistons' which are moved by the pressurized engine oil when advance or retard adjustment is required. The pressurized engine oil is supplied from the engine oil pump. The flow of the oil to the actuator is controlled by the VCT actuator solenoid valve which in turn is controlled by the ECM.
When advance or retard of the camshaft timing is required, the solenoid valve directs the pressurized engine oil into one side or the other of the central piston chambers. The central piston is attached directly to the camshaft. The hydraulic effect of the oil rotates the camshaft in relation to the outer gear of the VCT actuator, therefore changing the valve timing.