Camshaft Timing Chain
| ITEM | DESCRIPTION |
|---|---|
| 1 | Camshaft timing chain |
| 2 | Camshaft gear and VCT actuator - Exhaust camshaft |
| 3 | Camshaft gear and VCT actuator - Inlet camshaft |
| 4 | Camshaft timing chain and oil pump crankshaft drive gear |
| 5 | Camshaft timing chain guide |
| 6 | Bolt - camshaft timing chain guide (2 off) |
| 7 | Bolt (2 off) |
| 8 | Timing chain tensioner |
| 9 | Tensioner locking hole |
| 10 | Camshaft timing chain tensioner arm |
| 11 | Pin - tensioner arm pivot |
The simplex camshaft timing chain is an endless roller chain which is driven by a gear on the crankshaft. The chain is passed over the two gears which are integral with the VCT actuators on the end of each camshaft.
A fixed camshaft timing chain guide is fitted to the inlet side of the engine and secured with two bolts. A tensioner arm guide is fitted to the exhaust side of the engine and is attached with a pivot pin at its upper end. A camshaft timing chain tensioner is fitted to the lower end of the tensioner arm and applies a controlled tension to the chain. This maintains the chain at the correct tension and also allows for and dampens backlash in the chain tension due to deceleration.
The chain and tensioner are maintenance free components. The tensioner has a hole which allows for the locking of the tensioner to facilitate removal of the tensioner arm, guide or camshaft timing chain. The tensioner plunger can be pushed back into the housing and a pin inserted to lock it in the retracted position.
The tensioner is also responsible for lubrication of the timing chain. The tensioner is mounted in a oil pressure gallery on the cylinder block which also supplies pressurized engine oil to the turbocharger. Pressurized oil is passed through the tensioner body and into a drilling in the center of the tensioner plunger. The pressurized oil is ejected from a small hole in the end of the tensioner plunger and passed though a corresponding hole in the tensioner arm and apples engine oil to the chain.