With a weak timing belt tension, a violation of the valve timing is possible due to the belt jumping over the teeth on the camshaft pulley. In addition, a violation of the adjustment in any direction leads to increased wear on the timing belt.
To restore the tension of the timing belt, a tension roller 3 is installed in the camshaft drive mechanism (pic. 4.4), by turning which around an eccentrically located axis, the timing belt tension is adjusted.
To adjust the timing belt tension (camshaft drive) on the car you will need: ring wrench «at 17» (or socket head with ratchet), the key for turning the tension roller (in its absence, you can use two drills with a diameter of 4 mm and a large screwdriver).
1. Remove the front timing belt cover (camshaft drive) (see «Setting the piston of the first cylinder to the TDC position of the compression stroke»).
2. Smoothly (without jerks) turn the crankshaft at the pulley bolt about one turn clockwise (to make it easier to turn the crankshaft, you can turn out the spark plugs).
3. Turn the camshaft pulley a little, about two teeth, the crankshaft in the opposite direction (counterclock-wise), to loosen the tension on the drive chain of the timing belt.
4. Check the timing belt tension. A properly tensioned timing belt should rotate 90°with finger force (1.5-2 kgf), applied in the middle between the crankshaft and camshaft pulleys.
5. If the timing belt tension does not match the specified value, loosen the tension roller mounting nut. To tension the timing belt, turn the tension roller counterclockwise (about 10-15°), to loosen - clockwise.
6. If a special key is not available, insert two drill bits into the roller holes and turn the roller with a screwdriver.
7. Tighten the pulley nut and recheck the timing belt tension by following steps 2-4.
Pic. 4.4. Timing drive scheme (camshaft): 1 - a gear pulley of a cranked shaft; 2 - toothed pulley of the coolant pump; 3 - tension roller; 4 - rear protective cover; 5 - a gear pulley of a camshaft; 6 - timing belt; 7 - axis of the tension roller; And - an adjusting ledge on a back protective cover; B - mark on the camshaft pulley; C - mark on the oil pump cover; D - mark on the crankshaft pulley