The gap is adjusted in the following order. Remove the cylinder head cover and front toothed belt guard. The spark plugs are removed and the oil is removed from the oil baths in the cylinder head. Inspect the surface of the camshaft cams: they should not have scuffs, shells, wear and deep scratches. Install fixture 67.7800.9503 on the studs of the cylinder head cover for recessing the valve lifters. Instead of a fixture, you can use a mandrel 1 (pic. 50).
Pic. 50. Drowning (A) and fixing (b) valve lifters to replace the shim
Turn the crankshaft until the alignment marks on the pulley and the back cover of the toothed belt are aligned (see fig. 6), and then turn it another 40-50° (2.5-3 teeth on the camshaft pulley). In this case, there will be a combustion phase in the 1st cylinder. Turn the crankshaft only clockwise either by the bolt of the alternator drive pulley, or by the tool 67.7811.9509 by the camshaft pulley. It is not allowed to turn the crankshaft by the camshaft pulley bolt, as the bolt may be damaged.
Check the gaps at the 1st and 3rd camshaft cams with a set of probes. If the clearance differs from the norm, then with tool 67.7800.9503 or mandrel 1 (see fig. 50) sink the valve tappet and fix it in the lower position by installing a retainer 2 between the tappet edge and the camshaft (67.7800.9504).
Tool 67.7800.9506 (flat magnet steel plate) or forceps with narrow jaws remove the adjusting washer 3 and measure its thickness with a micrometer. Then determine the thickness of the new washer according to the formula H = B + (A - C), where H is the thickness of the new washer; A - measured gap; B is the thickness of the removed washer; C is the nominal gap.
Example. Let's say: A = 0.26 mm; B = 3.75 mm; C = 0.2 mm (for intake valve). Then H = 3.75 + (0,26 — 0,2) = 3.81 mm. Within the clearance tolerance of±0.05 mm, we accept the thickness of the new washer equal to 3.8 mm.
A new adjusting washer is installed in the valve tappet, retainer 67.7800.9504 is removed and the gap is checked again. If it is adjusted correctly, then the probe with a thickness of 0.2 or 0.35 mm should enter with a slight pinch. Sequentially turning the crankshaft half a turn, which corresponds to turning the mark on the camshaft pulley by 90°, adjust the clearances for the remaining valves, observing the sequence indicated in Table. 4. After adjustment, pour oil into the oil baths of the cylinder heads so that the contact points of the cams with the shims are in the oil. Install the cylinder head cover and front toothed belt cover.
Note. The cam numbers are counted in order from the camshaft pulley.