- Remove the timing cover as described in section 2.7.4.
- Drain the oil from the engine and remove the oil pan.
- Remove the chain tensioner. There are differences, however, as there are two designs of tensioning devices.
Sedis chain tensioner
Insert a screwdriver into the hole shown in Figure 29 and press the clamp until it comes off. After this, turn the screwdriver in the direction of the arrow. This locks the ratchet mechanism located below and the chain tensioner remains in a free position.
Renold chain tensioner
This tensioner does not have a self-locking feature, meaning it must be mechanically locked before being removed from the cylinder block. This requires a piece of wire that is placed around the chain tensioner according to figure 30. Tighten the ends of the wire so that the clamp cannot release from the tensioner.
With all tensioning devices
- Unscrew the two mounting bolts and remove the chain tensioner. The tensioner must be handled with care to ensure that its locking mechanism is not disturbed. There is a rod filter located under the chain tensioner, which should be removed immediately.
- In the order listed, remove the camshaft sprocket, crankshaft sprocket and camshaft. The camshaft sprocket is secured with a bar and three bolts.
Caution: The timing chain does not have installation markings. Therefore, before removal, in case of reinstallation, the chain and both sprockets must be marked with a paint line to ensure their subsequent installation in their previous relative positions.
- If necessary, you can unscrew the rear timing plate.
Check all timing drive components. The chain sprocket teeth or chain rollers may be damaged or worn. Clean the filter thoroughly.
Installation of the timing drive components is carried out as follows:
- Place a new paper gasket on the cylinder block and screw the board to the block. Tighten the bolts to a torque of 10 Nm.
- Place the chain sprocket onto the crankshaft from the front side. The key should fit into the groove, and the ignition timing mark should be located on the outside.
- Turn the crankshaft and camshaft so that the marks on both sprockets are located opposite each other. This is a very important work operation. After the stars have been placed, their relative positions should be compared with Figure 86.
Figure 86. Turn the crankshaft and camshaft until the ignition timing marks are aligned opposite each other.
- Place the chain on the crankshaft sprocket and insert the sprocket into the chain from the other side. Check that the marks are positioned as shown in Figure 87 and secure the sprocket to the camshaft. If the marks on the chain are not visible, the chain should be applied in accordance with the markings made during removal.
Figure 87. When applying the drive chain, ensure the correct positioning of the ignition timing marks.
- Place a new locking plate on the camshaft sprocket, install the three bolts and tighten the bolts to 23 Nm (Figure 88). Hammer the lock plate around the bolt heads.
Figure 88. The camshaft sprocket is secured to the shaft with three locking bolts.
- After following the above instructions for disassembling and assembling the tensioner, install the chain tensioner.
- Screw on the timing cover with a new gasket. In this case, the cover must be precisely centered, since the seal still needs to be pressed in. A piece of tube is used to press in the seal lubricated with engine oil. Place the oil seal on the timing cover, attach the tube and screw the large belt pulley nut onto the shaft. Under the pressure of the tube, the seal is pressed in. Tighten the cover bolts to 13 Nm.
- Drive a key into the crankshaft and drive the belt pulley onto the key and shaft. Block the crankshaft with a piece of wood in the crankcase and tighten the nut to a torque of 170 Nm.
- If the plate with the ignition timing scale has been unscrewed, it should be adjusted to determine the position of the top dead center.
- Turn the engine until the pistons of the first and fourth cylinders reach the exact position of top dead center, while the valves of the fourth cylinder should be in the switching phase, that is, one of the valves should open and the other should close. The exact position of the top dead center is determined using a dial indicator, which is positioned as shown in Figure 50.
- Screw on the plate with the indicator for setting the ignition timing so that the "zero" on the plate is located opposite the mark on the crankshaft belt pulley. Tighten both plate mounting nuts. Mark one of the nuts with paint (for subsequent purposes).
- All other work is carried out in reverse order.