Variable Camshaft Timing Units
The VCT units change the position of the camshafts in relation to the timing chains.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Bolt (3 off) |
| 2 | VCT unit |
| 3 | Filter |
| 4 | Camshaft |
| 5 | Inner plate |
| 6 | Housing and sprocket |
| 7 | Rotor assembly |
| 8 | Reed plate |
| 9 | Spring and lock pin |
| 10 | Spring (3 off) |
| 11 | Tip seal (3 off) |
| 12 | Spring (2 off) |
| 13 | Tip seal (2 off) |
| 14 | Spring |
| 15 | Dowel pin |
| 16 | Bias spring |
| 17 | Snap ring |
| 18 | Sensor wheel |
| 19 | Center plate |
| 20 | Snap ring |
| 21 | Screw (6 off) |
| 22 | Spool valve |
| 23 | Outer plate |
Each VCT unit is attached to the camshaft by three bolts. A rotor assembly and a reed plate are installed inside a sprocket housing, which consists of a sprocket, an outer plate and an inner plate held together by six screws.
A sensor wheel, for the CMP sensor, a center plate and a bias spring are installed at the front of the VCT unit. The ends of the bias spring locate on the center plate assembly and the sprocket housing, to give a turning moment to the camshaft in the advance direction. A snap ring locates the sensor wheel on to a sleeve installed in the center of the rotor assembly. The opposite end of the sleeve locates in a bore in the front face of the camshaft, which contains a filter.
A spring and spool valve are installed in the rotor assembly sleeve and retained by a snap ring. The spring keeps the spool valve in contact with the armature of the related VCT solenoid.
Each VCT unit is supplied with engine oil from an oil gallery in the cylinder head, through the camshaft front bearing cap and a bore in the center of the camshaft.