General information
2. During engine operation, the parts of the power plant, and in particular the gas distribution mechanism (GRM), heat up to high temperatures, resulting in thermal expansion and some increase in the size of the parts. To compensate for thermal deformations, it is necessary to have a certain gap between the camshaft cams and valve tappets.
3. With small clearances, the valves may not close completely, which will lead to a decrease in engine efficiency, and in some cases to deformation of the valves or burning of their seats.
4. With large gaps, the efficiency of the engine also decreases, increased mechanical noise occurs, and the engine operation becomes uneven.
5. When adjusting the clearances, it is necessary to take into account the condition of the valves - the seal in the valves is satisfactory, the valves do not have excessive clearances in the guides and the ends of the valve stems are not broken. If these conditions are not met, it is not possible to correctly adjust the thermal clearances.
6. Checking and adjusting the valves is performed as necessary, usually during the next scheduled maintenance, as well as after repair/disassembly of the timing belt or if there is noise during valve operation.
Note: Valve clearances are checked and adjusted on a "cold" engine - the engine has cooled to ambient temperature.
7. When performing the clearance check procedure, it is recommended to draw up a table/diagram with valve numbers in advance for ease of recording the measurement results.
8. Before starting work, disconnect the battery and, if necessary, remove the right front wheel (see Introduction).
Z16XEP Engine
Checking the gaps
9. Remove the air filter (see Chapter 4).
10. Remove the ignition module (see Chapter 1, Section 22)
11. Remove the cylinder head cover (see Section 10).
12. Bring the piston of the first cylinder to the TDC position of the end of the compression stroke (see Section 6), while the cams of the intake valves of the 2nd cylinder and the exhaust valves of the 3rd cylinder (see accompanying illustration) should be directed upwards and located symmetrically at a slight angle inwards (to the center of the cylinder head).
13. On these cams, using a blade-type feeler gauge (see accompanying illustration) check the gaps. If the gap exceeds/does not reach the standard value (see Specifications), determine the actual gap size using a set of feeler gauges and record the obtained value.
14. Turn the crankshaft half a turn in the direction of engine rotation - this corresponds to ¼ turn of the camshaft gears (follow the markings on the wheels). In this position, check the clearance on the cams of the intake valves of the 1st cylinder and the exhaust valves of the 4th cylinder. If the measurement result deviates from the standard, also write it down.
15. Turn the crankshaft another half turn - check the clearance on the cams of the intake valves of the 3rd cylinder and the exhaust valves of the 2nd cylinder.
16. Turn the crankshaft another half turn - check the valve clearance on the cams of the intake valves of the 4th cylinder and the exhaust valves of the 1st cylinder.
Adjusting the gaps
17. On this engine, valve clearance adjustment is performed with the camshafts removed. After removing the camshafts (see Section 10) extract using the KM-845 device (see accompanying illustration) valve adjusting bushings.
18. On the inside of the bushings (see accompanying illustration) the adjustment size is applied, which corresponds to bushings with a certain thickness - for example, size 20 corresponds to bushings with a thickness of 3.20 mm.
Note: A table of adjustment dimension values should be supplied with the bushings.
19. The thickness of the new adjusting sleeve is calculated using the formula: N = T + A - S
T = thickness of the removed bushing, (eg 3.20mm, adjustment size 20)
A = measured valve clearance (e.g. for intake valve - 0.31 mm)
S = valve clearance adjustment value (e.g. for intake valve – 0.25 mm)
For this example, the thickness of the new N adjusting washer should be 3.26 mm. The closest adjusting size to this value is 27 - 3.265 mm.
Note: Record and retain for possible future adjustments the dimensions of all installed bushings.
20. After completing the adjustment, reinstall all removed components. The operation for installing the cylinder head cover is described in detail in Section 10.
Z19DT Engine
Checking the gaps
21. Raise the vehicle on a lift and remove the engine crankcase guard (see Section 5).
22. Lower the vehicle and remove the engine cover (see Section 2).
23. Disconnect the 2 vacuum hoses by unscrewing the mounting bolts (see accompanying illustration).
24. Disconnect the 2 hoses, having first loosened and moved the clamps back completely (see accompanying illustration).
25. Loosen the mounting bolts and remove the camshaft housing cover (see accompanying illustration).
26. Turn the crankshaft so that the cams of the first pair (see accompanying illustration) were directed upward.
Note: The methods for turning the crankshaft are given in Section 6.
27. Check the clearances of the specified cams using a set of blade feeler gauges - the appropriate feeler gauge (see Specifications) should fit into the gap very tightly with a slight "bite", otherwise the gap needs to be adjusted. If the gap value deviates from the standard values, it is necessary to determine the actual value of the gap - write down the measured value.
28. Turn the crankshaft half a turn in the direction of engine rotation and check the valve clearances at the second (see illustration 9.26) pairs of cams (the cams should be pointing upwards). If the clearance value deviates from the control value, record the result of the actual measurements. Then turn the crankshaft another half turn and check the valve clearance at the third and fourth (see ibid) pairs of fists.
Adjusting the gaps
29. Turn the crankshaft so that the cam of the valve to be adjusted is turned with the heel towards the tappet.
Note: Make sure the engine is not at TDC for the valve in question, as replacing the adjusting shim will require compressing the valve spring, which could cause the valve to hit the piston crown.
30. Turn the cup pusher with the groove facing outward (see accompanying illustration).
31. If you do not have the special tool Opel-EN-46797 and EN-46799 at hand, insert a large flat-blade screwdriver between the edge of the tappet and the base of the camshaft. Carefully, using the screwdriver as a lever, push the tappet down until you can remove the adjusting washer. The easiest way to remove the washer is with a magnetized rod (see accompanying illustration).
32. Wipe the washer and measure its thickness with a micrometer.
Note: The washers are marked (see accompanying illustration), which, however, may be lost as a result of wear and tear.
33. The thickness of the new adjusting washer is calculated using the formula: N = T + A - S
T = thickness of the removed washer (for example - 3.15 mm)
A = measured valve clearance (e.g. 0.45 mm)
S = valve clearance adjustment value (e.g. 0.35 mm)
For this example, the thickness of the new adjusting washer N= 3.25 mm.
Note: It may be possible to make the required adjustment by simply swapping the washers from one lifter to the other. Record and save the thickness of all washers for possible future adjustments.
34. Prepare a washer of the required thickness, lubricate it with clean engine oil. Press the pusher and place the washer in it with the marking facing down.
35. Proceed in a similar manner to adjust the clearances of the remaining valves that require adjustment.
36. Rotate the crankshaft several times to seat the washers on the tappets, then perform a control check of the clearances before installing the camshaft housing cover. Clean the sealing surfaces and install the cover on a new gasket. Tighten the 7 bolts to 10 Nm.
37. Reinstall all removed components. Install the engine guard and wheel, then lower the vehicle to the ground and tighten the wheel bolts to the required torque. Reconnect the battery.
Z17DT(L/H) Engines
Checking the gaps
38. To check and adjust the valves, it is necessary to remove the injectors (see Chapter 4).
Attention: The fuel system is very sensitive to the ingress of even small particles of contamination - strictly follow all the instructions in the relevant section, otherwise the system may fail and costly engine repairs will be required!
39. Turn the crankshaft so that the cams of the corresponding pairs (see accompanying illustration) were directed upward.
40. Check the valve clearances of the specified pairs using a set of blade feeler gauges - the appropriate feeler gauge (see Specifications) should fit into the gap very tightly with a slight "bite", otherwise the gap needs to be adjusted. If the gap value deviates from the standard values, it is necessary to determine the actual value of the gap - write down the measured value. Adjustment can be made immediately or after checking the gaps of all valves.
41. Then check and adjust the gaps in turn at the second and sixth, third and fifth, first and fourth (see accompanying illustration) pairs of cams, each time turning the engine crankshaft half a turn in the direction of rotation (clockwise) — the cams of both adjustable pairs must point upwards.
Gap adjustment
42. The valve clearance is adjusted by replacing the adjusting washers. To remove the old washers, turn the cup tappet so that the tappet groove points outward, then press the cup tappets using the special tool Opel-KM-6090 (see accompanying illustration).
[Original source is on the website: www.opelbook.ru]
Attention: When using this tool, pay attention to the marking: "IB" for intake valves, "EX" for exhaust valves!
43. The procedure for calculating the thickness of a new adjusting washer is given in paragraph 33. Before installing the washer, lubricate it with clean engine oil.
44. After completing the adjustment, turn the crankshaft several times to seat the washers on the tappets and check the clearances on all valves again. Install all removed components back in place.
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