4-cylinder petrol engine
Removing
Up to 9/93: Remove V-belt, see later in this chapter.
From 10/93: Remove the V-belt and, if present, the tensioner pulley, see later in this chapter.
Set the crankshaft to the TDC position for cylinder 1 and do not change the setting any more, see chapter «Ignition system».
Unscrew both V-belt pulleys or vibration damper from crankshaft.
Remove upper and lower toothed belt guards.
Mark with an arrow on the toothed belt using a felt-tip pen or marker the direction of its movement when the engine is running.
Loosen and remove toothed belt.
Caution: With the toothed belt removed, do not change the engine setting if possible.
Installation
Place the toothed belt on the gear wheels of the crankshaft and intermediate shaft.
Attention: The arrow marked on the belt must point in the direction of rotation of the motor shaft.
Install the crankshaft pulley with one bolt. Fasten the vibration damper of the injection engine with all four bolts.
Check if the camshaft is in the TDC position for cylinder 1. At the same time, the marks on the belt pulleys of the crankshaft and intermediate shaft must match (arrow) on the right picture. The crankshaft is at TDC for cylinder 1.
Attention: For an engine with the designation AEK, the position of the mark on the gear wheel of the intermediate shaft does not matter. Crankshaft TDC for cylinder 1 is checked through an inspection hole in the gearbox housing. Namely: through a round hole it should be visible that the mark «ABOUT» on the flywheel is located opposite the mark on the crankcase. Check if the slider in the ignition distributor housing shows the TDC mark for cylinder 1 (figure 28-345), if necessary, tighten the countershaft wheel accordingly in the direction of rotation of the engine crankshaft, see chapter «Ignition system».
Attention: For engines with a rear toothed belt guard, the TDC mark on the camshaft sprocket must match the TDC mark on the guard.
If necessary, turn the camshaft until the mark on its gear wheel matches the mark on the cylinder head cover or toothed belt guard.
Attention: If the camshaft must be rotated through a large angle, make sure that none of the pistons is in the TDC position, otherwise the valves or pistons may be damaged. If necessary, turn crankshaft by approx. 90° (1/4 turn) in a clockwise or counterclockwise direction. However, the belt pulley must not rotate more than 90°as a whole.
Place toothed belt on camshaft sprocket.
Attention: When applying a toothed belt, do not change the position of either the camshaft, crankshaft or intermediate shaft. Otherwise, serious damage to the engine may occur or it will no longer produce its full power. After the toothed belt has been tensioned, check again the adjustment of the camshaft, intermediate shaft and belt pulley. This means: If the mark on the camshaft sprocket matches the mark on the protective screen, then at the same time the mark on the crankshaft pulley must match the mark on the countershaft sprocket. Otherwise, it is necessary to repeat the adjustment of the camshaft gear and belt pulley with the toothed belt removed.
Pull on toothed belt.
Rotate the crankshaft two turns in the direction of engine rotation and check the adjustment again.
Remove the crankshaft pulley.
Install the lower toothed belt cover.
Install the upper belt cover.
Install the crankshaft pulley and tighten to 20 Nm (for an engine with the designation AEK - a torque of 25 Nm).
Install and tighten the V-belt, see later in this chapter.
Install poly V-belt and tension roller (20 Nm), tension the V-ribbed belt, see later in this chapter.
Check ignition timing, adjust if necessary.
Attention: For repairs that require the removal of the timing belt from the camshaft timing gear only, adjust the timing belt as follows:
Set the crankshaft to TDC for cylinder 1, see chapter «Ignition system».
The mark on the camshaft sprocket must match the mark on the cylinder head cover, see Figure 13-689.
Loosen the toothed belt and remove it from the camshaft gear.
Attention: After this, the position of the crankshaft and the intermediate shaft must not be changed any more.
Attach toothed belt and tighten.
Remove the ignition distributor cap. Check if the slider in the distributor housing points to the TDC mark for cylinder 1.
If this is not the case, turn the ignition distributor so that the marks match. If necessary, reinstall the ignition distributor, see chapter «Ignition system».
Turn the crankshaft twice and check that the marks on the camshaft and crankshaft match the corresponding marks on the casings.
Check ignition timing, adjust if necessary, see chapter «Ignition system».
Start the engine. A whistle coming from the toothed belt indicates too much belt tension.
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