Removal and installation of a chain of the gas distribution mechanism

Withdrawal

1. Turn the engine to TDC for cylinder #1 (paragraph 4).

2. Remove the MGR cover (paragraph 9).

3. Remove the disk of the pulse shaft position sensor from the crankshaft, taking into account which side it is installed. Mark the position of the sensor for its subsequent correct installation (see fig. 10.3).



4. Temporarily screw the crankshaft pulley bolt into the end of the crankshaft so that it can be rotated.

5. Please note that the chain for each head of the block must be removed at the position of the crankshaft corresponding to this head of the block. In this case, the camshafts experience the same force from the springs of various valves. To remove the rear head chain, rotate the shaft until its key is in the 3 o'clock position. The corresponding mark on the rear head outlet camshaft sprocket should be in the 12 o'clock position. A similar mark on the rear head intake camshaft sprocket should be in the 3 o'clock position.

6. If there are no marks on the chains, apply them by dripping paint onto the chain opposite the mark on the sprocket. If the marks are already there, then it is unlikely that they are aligned with the marks on the sprockets, but they will come in handy when installing the chains. Usually such marks are made in the form of a spot of white paint or copper plating of a chain link.


7. Turn out bolts of a chain tensioner of a back head of the block. Remove the chain guide from its hinge (see fig. 10.7, a-c).

Note: On older models, an adapter plate may be installed between the tensioner and cylinder block.

8. Remove the chain from the sprockets of the crankshaft and camshafts (see fig. 10.8, a, b). If you install the same chain again, then it should have the appropriate labels.



9. Remove the fixed chain guide bolts (see fig. 10.9).




10. Pull off the sprocket from the crankshaft, considering which side it is installed. Mark it for installation in the same position (see fig. 10.10).



11. To remove the front head chain, rotate the shaft until its key is in the 11 o'clock position. The corresponding mark on the front head intake camshaft sprocket should be in the 9 o'clock position. A similar mark on the front head outlet camshaft sprocket should be in the 12 o'clock position.

12. Turn out bolts of a chain tensioner of a forward head of the block. Remove the chain guide from its hinge (see fig. 10.12, a-c).

Note: On older models, an adapter plate may be installed between the tensioner and cylinder block.

13. Remove the chain from the sprockets of the crankshaft and camshafts (see fig. 10.13, a, b). If you install the same chain again, then it should have the appropriate labels.



14. Remove the bolts of the fixed chain guide (see fig. 10.14).



15. Pull off the sprocket from the crankshaft, considering which side it is installed. Mark it for installation in the same position (see fig. 10.15).

Inspection

Note: All required components must be labeled for proper installation.

16. Clean and dry all components.

17. Inspect chain tensioners and guides for excessive wear or other damage. The guides should not have deep marks from the chains.

18. Inspect chains for excessive wear. Holding them horizontally, check the play in the chain links. Replace chains if necessary.

19. Check the crankshaft and camshaft sprockets for excessive wear or other damage. Camshafts are made in one piece with sprockets. Therefore, when the sprocket is worn, the shaft must be replaced.

20. Before installing the tensioners, their pistons must be compressed and blocked. Insert a small screwdriver into the tensioner hole and release the ratchet. Clamp the tensioner in a soft-jawed vise and push the piston in. into a cylinder. Then block the piston by inserting a piece of wire with a diameter of 1.5 mm into a special hole.

Installation

21. If necessary, rotate the crankshaft so that the key is in the 11 o'clock position corresponding to the front head chain setting.

22. Check up labels on asterisks of camshafts of a forward head of the block. The intake camshaft sprocket should be at the 9 o'clock position and the exhaust camshaft sprocket at the 12 o'clock position.

23. Install the fixed chain guide and tighten the bolts.

24. Put the chain on the camshaft sprockets, aligning the marks (see fig. 10.24).



25. Enter the crankshaft sprocket into engagement with the chain, aligning the marks, then put the sprocket on the crankshaft, seating it on the key (see fig. 10.25). In this case, the front branch of the chain must be pressed against the fixed guide, and the rear branch must be loosened.



26. Install the movable guide on its hinge, then install the tensioner (and adapter plate, if any). Tighten the bolts to the required torque. Check if the marks are aligned, then unlock the tensioner piston. Due to the high force of the tensioner spring, it is necessary to press the guide against the tensioner when pulling out the blocking piece of wire, and then gradually release it (see fig. 10.26, a-c).






27. If necessary, turn the crankshaft so that the key is in the 3 o'clock position corresponding to the installation of the rear head chain.

28. Put an asterisk on a cranked shaft.

29. Check up labels on asterisks of camshafts of a back head of the block. The exhaust camshaft sprocket should be at the 12 o'clock position and the intake sprocket at the 3 o'clock position.

30. Install the fixed chain guide and tighten the bolts.

31. Put the chain on the sprockets of the crankshaft and camshafts, matching the marks. In this case, the front branch of the chain must be pressed against the fixed guide, and the rear branch must be loosened.

32. Install the movable guide on its hinge, then install the tensioner (and adapter plate, if any). Tighten the bolts to the required torque. Check if the marks are aligned, then unlock the tensioner piston.

33. Put the disk of the crankshaft position sensor on the shaft, aligning the keyway (with blue mark) keyed disc. The disc must be labeled «2.5 L» And «FRONT» (see fig. 10.33).



34. Temporarily install the crankshaft pulley bolt and rotate the crankshaft until its key is in the 11 o'clock position.

Note: After turning the crankshaft, the chain marks move away from the sprocket marks, but the marks on the camshaft sprockets should point towards each other.

35. Install chain cover (paragraph 9).