Checking and adjusting the timing valves (Opel Vectra C)

1. Most of the engines discussed in this Manual are equipped with valve tappets with hydraulic compensators. The valve clearance value on such engines is set automatically and does not require adjustment. Below is a description of the checking and adjustment procedures only for diesel engines that require adjustment of thermal clearances - Z19DT and Y30DT.

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 remove the right front wheel

Note: After each battery disconnection, the steering wheel angle sensor must be adjusted.

Z19DT Engine

Checking the gaps

9. Raise the vehicle on a lift and remove the engine crankcase guard.

10. Lower the vehicle and remove the engine cover.

11. Loosen the mounting bolts and disconnect the 2 vacuum hoses (see illustration).



12. Disconnect the 2 hoses, having first loosened and moved the clamps back completely (see illustration).





13. Loosen the mounting bolts and remove the camshaft housing cover (see illustration).



14. Turn the crankshaft so that the cams of the first pair (see illustration) were directed upward.



15. Check the clearances of the specified cams using a set of blade feeler gauges - the appropriate feeler gauge should fit into the clearance very tightly with a slight "bite", otherwise the clearance needs to be adjusted. If the clearance value deviates from the standard values, it is necessary to determine the actual clearance value - write down the measured value.

16. Turn the crankshaft half a turn in the direction of engine rotation and check the valve clearances at the second (see illustration 9.14) 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

17. 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.

18. Turn the cup pusher with the groove facing outward (see illustration).

19. If you don't have a special device at hand Opel-EN46797 and EN-46799 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 the adjusting washer can be removed. The easiest way to remove the washer is with a magnetized rod (see illustration).





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20. Wipe the washer and measure its thickness with a micrometer.

Note: The washers are marked (see illustration).

21. 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 (for example - 0.45 mm)
S = valve clearance adjustment value (for example - 0.35 mm)
For this example, the thickness of the new adjusting washer N= 3.25 mm.

Note: Shims may be reused if they show no obvious signs of wear. It may be possible to make the required adjustment by simply swapping the washers from one tappet to the other. Record and retain for future reference the thickness of all washers. If the thickness markings on a washer are worn off and illegible, further use of the washer is not recommended.

22. 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.



23. Turn the crankshaft in the direction of engine rotation (clockwise) half a turn and proceed in a similar manner to adjust the clearances for the second pair of cams, then turn the crankshaft another half a turn and adjust the clearances of the remaining valves that need adjustment.

24. 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, repeat the adjustment if necessary. Clean the sealing surfaces and install the cover on a new gasket. Tighten the 7 bolts with a force 10 Nm.

25. 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.

Y30DT Engines

26. The procedure for adjusting the valve clearances on the Y30DT engine is similar to that described above.

Note: A different special tool is used to remove the washers.