Removal and installation of a toothed belt

Attention! When using the bus as a taxi or for frequent trips over short distances, 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 a dead point for the 1st cylinder. To do this, turn the crankshaft pulley (at idle) before reaching the top dead center position for the first cylinder (see arrow). Never turn the crankshaft with the toothed belt gear.

• the crankshaft is at top dead center of the first cylinder, and if the cam pair of the first cylinder points up, see section "Valve clearance adjustment".
• at the same time, the marking on the flywheel must align with the pulley (see arrow). In this position, a setting ruler can be inserted into the slot of the cam pulley.
• lock the camshaft with a setting ruler. The ruler has a protrusion that prevents the camshaft from turning.

Setting ruler adjustment

Turn the locked camshaft so that one of the ends of the setting ruler rests on the cylinder head. At the other end of the ruler, use a measuring roller to check the resulting gap. Insert a measuring template with the 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 of the cylinder head at the other end.




Lock the fuel pump gear with a locking mandrel.

Loosen the tension roller nut and release the toothed belt.

Attention! If the camshaft turns with the toothed belt removed, neither piston should be at top dead center. Otherwise damage to pistons or valves may occur.

Slowly turn the camshaft, then before that you need to set all the pistons to the same position below the top dead center.

To do this, on the top of the crankshaft belt pulley, make a mark with chalk (provided that the camshaft is in the position of the top dead center of the first cylinder), then turn the camshaft pulley a quarter of a turn (90 deg.) right or left. The chalk mark will show when viewed in the direction of travel, forward or backward.

Loosen and remove V-belt (see section "V-belt replacement").

Remove the V-belt pulley and lower toothed belt guard.

Installation

• in the hole of the gearbox, check whether the dead center mark on the flywheel coincides with the control mark.
• Loosen the camshaft wheel mounting bolt 1/2 turn. Unclip the wheel from the cone using a rubber mallet.

Attention! Models from 2.84 have a sealed gear guard fitted. In these vehicles, the camshaft wheel is disengaged from the cone through a 6mm hole in the rear casing using a mandrel and a hammer.

• put on the gear wheel according to fig. 13-693 and remove the fuel pump gear lock mandrel.
• tension the toothed belt.
• tighten the tension roller nut with a torque of 45 Nm.
• Tighten the camshaft wheel mounting bolt to 45 Nm.
• remove the setting line.
• Rotate crankshaft 2 turns in direction of rotation. Hit the toothed belt between the camshaft wheel and the fuel pump gear with a rubber mallet, and check the belt tension again, tighten the belt if necessary.
• check the start of delivery of the fuel pump, see section "Checking and adjusting the start of delivery of the fuel pump".
• fit the V-belt pulley and lower cover, tension the V-belt, see section "V-belt tension".
• Install the gearbox opening cover.
• replace the gaskets and screw on the cylinder head cover, see section "cylinder head".
• install the toothed belt cover.