- the pressure in the engine lubrication system has dropped. The cause of this malfunction is often increased wear of the camshaft journals and camshaft bearing beds in the cylinder head. If the beds and their covers are worn out, the cylinder head is replaced as an assembly, since the beds are made directly in its body;
- valve knocking with normal clearances in the valve drive mechanism. Caused by increased wear of the camshaft cams due to the use of low-quality motor oil or as a result of damage to the oil filter.
You will need: TORX E14 socket head, extension, ratchet, 24 mm keys and TORX T55.
1. Disconnect the wire from the negative terminal of the battery.
2. Press the lock…
3. …and disconnect the wiring harness connector from the electro-hydraulic valve of the exhaust camshaft.
4. Similarly, disconnect the wiring harness connector from the electro-hydraulic valve of the intake camshaft.
5. Remove the timing belt from the camshaft pulleys (see Replacing the timing belt).
6. Remove the cylinder head cover (see Replacing the cylinder head cover gasket).
7. Using a wrench to hold the exhaust camshaft from turning, unscrew the toothed pulley mounting bolt plug…
8. …and remove the plug.
9. In a similar manner, unscrew and remove the plug of the intake camshaft.
10. While holding the exhaust camshaft from turning, remove the toothed pulley mounting bolt…
11. …and remove the pulley.
12. Similarly, unscrew the bolt and remove the toothed pulley of the intake camshaft.
13. Replace the sealing gaskets of the camshaft toothed pulley bolt caps, regardless of their condition.
14. Remove the right powertrain suspension support (see Replacing the right powertrain suspension support)
15. Unscrew the bolts securing the engine bracket to the cylinder block and remove the bracket.
16. Remove the three upper bolts…
17. …and one lower bolt securing the upper timing gear housing.
18. Overcoming the resistance of the clamps, disconnect the wiring harness holder from the upper casing.
Note: This is how the wiring harness holder retaining clips are positioned.
19. Remove the upper drive belt cover.
20. Remove the bolts securing the front camshaft bearing cover to the cylinder head…
21. …and remove the lid.
22. Clean the mating surfaces of the cylinder head…
23. …and the front cover of the camshaft bearings.
24. Remove the intake and exhaust camshaft oil seals from their seats in the cylinder head.
25. Replace the camshaft seals regardless of their condition.
Fig. 1. Sequence of unscrewing the bolts securing the camshaft bearing caps
26. Loosen the exhaust camshaft bearing cap mounting bolts in the sequence shown in Fig. 1.
27. Finally, unscrew the bolts, remove the camshaft bearing caps…
28. …and remove the exhaust camshaft.
29. Similarly, in the sequence indicated on fig. 1, unscrew the bolts securing the intake camshaft covers, remove the covers..
30. …and then the intake camshaft.
Attention! The camshaft bearing caps are processed together with the cylinder head beds, so they cannot be depersonalized. The bearing ordinal numbers are stamped on the caps. The numbers made in the casting are technological for the cap casting process and do not serve as a guide for installing the caps. Install the camshaft bearing caps in strict accordance with the markings applied to them.
31. Inspect the camshafts. The bearing journal surfaces…
32. …and the cams must be well polished and without damage. No burrs, nicks, scratches, or aluminum drag from the bearing seats in the cylinder head are allowed on the working surfaces of the journals.
If signs of seizure, overheating, deep scratches or wear in the form of faceting are found on the working surfaces of the cams, replace the shafts.
Attention! Grinding of camshaft cams to eliminate step wear is prohibited, since changing the cam profile dimensions will disrupt the valve timing.
33. In workshops equipped with special tools and devices, you can check the radial runout of the camshaft journals. If the runout value is more than 0.02 mm or if the journals are not aligned, replace the shaft, since its straightening is not allowed.
34. Lubricate the camshaft beds with clean engine oil and place the camshafts in them.
Fig. 2. Sequence of screwing in the camshaft bearing cap mounting bolts
35. Install the camshaft bearing caps and tighten their mounting bolts evenly, moving from bolt to bolt through every other turn, in the sequence shown in Fig. 2, to the torque.
[Information taken from the website www.opelbook.ru]
36. Press the exhaust and intake camshaft oil seals into the cylinder head sockets (see Replacing camshaft seals).
37. Adjust the valve clearance (see Adjusting valve clearances).
38. Install the remaining removed parts in the reverse order of removal.
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