Attention! When using the bus as a taxi or for frequent short-distance trips, the toothed belt must be replaced every 120,000 km.
Dismantling
- remove the upper casing and cylinder head cover.
- remove the plastic cover from the gearbox.
- (13-597) Turn the crankshaft to the dead center for the 1st cylinder. To do this, turn the crankshaft belt pulley (at idle) until reaching the top dead center position for the first cylinder (see arrow). Never turn the crankshaft using the timing belt gear.
- the crankshaft is at the top dead center of the first cylinder, and if the cam pair of the first cylinder points up, see section "Adjusting valve clearance".
- at the same time, the marking on the flywheel must coincide with the pulley (see arrow). In this position, a setting ruler can be inserted into the spline of the cam pulley.
- lock the camshaft using a setting ruler. The ruler has a protrusion that prevents the camshaft from turning.
Adjusting the installation ruler
Turn the locked camshaft so that one end of the installation ruler rests against the cylinder head. At the other end of the ruler, use a measuring roller to check the resulting gap. Insert a measuring template with a gap value reduced by half between the ruler and the cylinder head. Turn the camshaft until the ruler rests on the gauge. Insert a second measuring gauge with the same set value between the ruler and the cylinder head at the other end.
Lock the fuel pump gear using a locking mandrel.
Loosen the tension roller nut and release the timing belt.
Caution! If the camshaft is turned with the timing belt removed, no piston should be at top dead center. Otherwise, damage to the pistons or valves may occur.
Slowly turn the camshaft, but before this you need to set all the pistons to the same position below the top dead center.
To do this, make a mark with chalk on the top of the crankshaft belt pulley (provided that the camshaft is in the top dead center position of the first cylinder), then turn the camshaft pulley a quarter turn (90 degrees) to the right or left. The chalk mark will show whether it is forward or backward when viewed in the direction of travel.
Loosen and remove the V-belt (see section "Replacing the V-belt").
Remove the V-belt pulley and the lower timing belt cover.
Installation
- in the gearbox hole, check whether the dead point marking on the flywheel matches the control mark.
- loosen the camshaft wheel mounting bolt by 1/2 turn. Use a rubber hammer to loosen the wheel from the cone.
Note! Models starting with 2.84 have a sealed gear guard. In these vehicles, the camshaft gear is disengaged from the cone through a 6mm hole in the rear guard using a mandrel and hammer.
- put the toothed wheel on according to Fig. 13-693 and remove the locking mandrel of the fuel pump gear.
- tighten the toothed belt.
- tighten the tension roller nut to a torque of 45 Nm.
- tighten the camshaft wheel mounting bolt to a torque of 45 Nm.
- remove the installation ruler.
- turn the crankshaft 2 revolutions in the direction of rotation. Hit the toothed belt between the camshaft wheel and the fuel pump gear with a rubber hammer and check the belt tension again, tighten the belt if necessary.
- check the start of the fuel pump, see section "Checking and adjusting the fuel pump start".
- install the V-belt pulley and lower casing, tighten the V-belt, see section "Tensioning the V-belt".
- install the gearbox opening cover.
- replace the gaskets and screw on the cylinder head cover, see section "Cylinder head".
- install the timing belt cover.
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