Valve timing mechanism (VAZ-2107)

Clearances in the valve drive mechanism

Every 10,000 km mileage, and on a new car after the first 2000-3000 km, check the gaps "A" (Fig. 25) between the cams and levers, which should be equal to 0.15 mm on a cold engine for both intake and exhaust valves.



On a new engine, check and tighten the cylinder head, camshaft bearing housing, intake manifold and exhaust manifold before performing this operation.

Loosen the cylinder head bolts approximately 30° each beforehand and tighten them in the order shown in Fig. 26. The tightening torque for bolts 1–10 should be 115 N⋅m (11.5 kgf⋅m), and for bolt 11 – 38 N⋅m (3.8 kgf⋅m).



Tighten the camshaft bearing housing fastening nuts with uniform force in the order shown in Fig. 27. The final tightening torque for the nuts is 22 Nm (2.2 kgf·m).





To adjust the gaps:

• remove the cylinder head cover;
• rotating the crankshaft* clockwise, align the mark "A" (Fig. 28) on the sprocket with the mark "B" on the camshaft housing; in this case, the piston of the fourth cylinder is at TDC at the end of the compression stroke and both valves are closed;
• adjust the clearances between the levers and the camshaft cams at the exhaust valve of the 4th cylinder (8 cam) and the intake valve of the 3rd cylinder (6 cam); to do this, loosen lock nut 2 (Fig. 29) and, by turning adjusting bolt 1, set the required clearance with a flat feeler gauge inserted between the cam and the lever;
• holding bolt 1 in this position with a wrench, tighten lock nut 2 to a torque of 52 Nm (5.2 kgf·m) and check the gap again;
• turning the crankshaft half a turn, adjust the clearances in the sequence indicated in Table 3;
• put the cover back in place.

After finishing the work, check the ratchet tightening torque. It should be 122 Nm (12.2 kgf·m).

* This is done with a special wrench on the ratchet or by rotating the jacked up rear wheel with fourth gear engaged and stops installed under the front wheels.