Camshaft Drive Mechanism Diagram
1 – camshaft sprocket; 2 – chain; 3 – chain tensioner; 4 – oil pump drive shaft sprocket; 5 – crankshaft sprocket; 6 – limiting finger; 7 – tensioner shoe; 8 – chain tensioner
Section of chain tensioner
1 – cap nut; 2 – tensioner housing; 3 – rod; 4 – spring ring; 5 – plunger spring; 6 – washer; 7 – plunger; 8 – spring; 9 – cracker; 10 – spring ring
Device 67.7824.9521 for checking chain wear (stretching)
1 – roller; 2 – adjusting nut; 3 – counterweight
Camshaft drive chain (see fig. Diagram of the camshaft drive mechanism) with semi-automatic tensioner 8.
1. To adjust the chain tension, loosen the cap nut 1 (see fig. Section of chain tensioner) and turn the crankshaft 1–1.5 turns in the direction of rotation. In this case, the tensioner spring 8, acting on the shoe, will automatically adjust the chain tension.
2. Then tighten tensioner nut 1.
3. To disassemble the chain tensioner, remove cap nut 1, clamp cracker 9 and spring ring 4, then take out plunger 7, spring 5 and rod 3 together with spring 8 and washer 6.
4. After disassembly, check for burrs 9 and rod 3, and for deep scratches on the mating surfaces of the shoe and plunger of the chain tensioner. Replace damaged parts.
5. The elasticity of the tensioner spring 8 must be within the limits indicated in the figure. The worn tensioner shoe and chain guide are replaced with new ones.
6. The chain is first washed in kerosene, and then the condition of its links is checked. No chips, cracks or other damage are allowed on the rollers and cheeks. When the engine is running, the chain is stretched. It is considered operational if the tensioner ensures its tension, i.e. if the chain has stretched no more than 4 mm.
7. Check the chain stretch using device 67.7824.9521 (see Fig. Device 67.7824.9521 for checking chain wear (stretching)), which has two stepped rollers 1, onto which the chain is placed. Using counterweight 3, the chain is stretched with a force of 294 N (30 kgf) or 147 N (15 kgf). Adjusting nut 2 ensures that the counterweight axis is parallel to the base of the device.
8. Stretch the chain with a force of 294 N (30 kgf) by moving the counterweight to the extreme right position, then reduce the force by 147 N (15 kgf) by moving the counterweight to the extreme left position.
9. Repeat both operations once more and determine the chain extension by the distance L between the axes of rollers 1. By measuring the distance between the diameters d of the rollers with a caliper and adding the diameter d to it, you will obtain the distance L between the axes of the rollers.
10. For a new chain, the distance L between the roller axes is 485.755+0,5-0,1 mm for engine 2101 and 495.3+0,5-0,1 mm for engine 2103.
11. If the chain has stretched to 490 mm for the 2101 engine or to 499.5 mm for the 2103 engine, it should be replaced.
12. Before installing on the engine, lubricate the chain with engine oil.