Bringing the piston of the first cylinder to the top dead center (TDC) position (Opel Corsa C)

General information

1. Top dead center (TDC) is the highest point of the piston stroke in its cylinder. In 4-stroke engines, during the rotation of the crankshaft, this position is reached by each of the pistons twice during one working cycle: once at the end of the compression stroke and the second time at the end of the exhaust stroke. Determining the exact position of the TDC of the piston at the end of the compression stroke (usually the first cylinder) is of great importance for many subsequent works, for example, for replacing the toothed belt, checking the valve timing and replacing the cylinder head gasket. Sometimes the TDC of the compression stroke is also called the ignition timing.

Note: Cylinder numbers are counted in sequence from 1 to 4. The first cylinder is located on the accessory/timing drive side.

2. Checking and adjusting the valve timing is a very labor-intensive operation and can only be performed using a special Opel tool, make sure in advance that all the necessary accessories are available and at hand. This tool is usually only available at a service station.

3. To bring the piston of the first cylinder to TDC, it is necessary to turn the crankshaft evenly and slowly so that the TDC marks coincide. Depending on the conditions, turning the engine crankshaft can be done in the following ways:

• Raise one of the front wheels and place the car on a stand. Engage 5th gear - when turning the raised wheel, the engine crankshaft will turn (models with manual transmission). Use an assistant to turn the wheel when making adjustments.
• If you don't have any jacking devices at hand, choose a flat, fairly large area and engage 5th gear. When moving the car by pushing, the crankshaft will also turn (models with manual transmission).
• In stationary conditions, the crankshaft is turned using a ratchet wrench and a change of head ("E18"), which is installed on the central bolt of the crankshaft pulley, while the neutral gear must be engaged and the parking brake must be cocked. The crankshaft should be turned clockwise (if you look from the timing drive side).

Caution: Do not turn the engine by the camshaft gear mounting bolt - this will put too much tension on the timing belt/chain!

4. Before starting work on setting the TDC, disconnect the wire from the negative terminal of the battery (see Chapter 5) and remove the air cleaner (see Chapter 4).

Note: On models from 2004 onwards, equipped with the ESP system, a steering wheel angle sensor is installed on the steering column. After each battery disconnection, when completing work, it is mandatory to reprogram this device using special devices.

Engines Z10XE(P)/Z12XE/Z14XEP

Examination

5. Disconnect the wiring connectors of the camshaft sensor, engine oil pressure switch, and coolant temperature sensor. Separate the cable duct box on the right side of the engine and move it to the side. Disconnect the 2 crankcase ventilation system (PCV) hoses and remove the ignition module (see Chapter 5). Unscrew the 13 cylinder head cover mounting bolts and remove it.



6. Raise the car on a lift or place it on stands. Remove the multi-rib belt cover and, on Corsa-Eco models, remove the crankcase guard (see Section 5).

7. Turn the crankshaft in the direction of engine rotation (clockwise) so that the mark on the shaft pulley coincides with the lug on the timing cover (see accompanying illustration).



8. In the TDC position of the compression stroke, the camshaft cams of the first cylinder should be turned outward from the center of the engine (see accompanying illustration). Otherwise, turn the crankshaft one more full revolution.





9. To check the TDC position using special devices, do not bring the crankshaft to the alignment of the marks by approximately 15-20° and unscrew the plug closing the crankshaft locking hole (see illustration 6.7).

10. Install the KM-952 device into the hole (see illustration 6.7), slowly and smoothly turn the crankshaft until the device enters the special groove of the shaft (will fix the shaft) - in this case, the marks on the crankshaft pulley and on the timing drive cover should match, and the timing cams above the first cylinder should take the corresponding position (see above).

11. Install into the camshaft grooves (from the flywheel side) special device KM-953 (see accompanying illustration) - the projections of the device must enter the grooves to the greatest possible depth. If it is not possible to install the device, it is necessary to adjust the valve timing (see below).



12. Install the special device KM-954 (see accompanying illustration) so that the projection of the device fits into the recess of the camshaft sensor rotor. If the projection and recess do not match, adjust the valve timing (see below).

Adjustment

13. After completing the check, remove the KM-953 and KM-954 devices from the engine. Caution: Under no circumstances should the control devices be used to hold the engine shafts from turning!

14. Unscrew the bolt, freeing the hole for installing the KM-955-1 device (see illustration 6.14a) Using an open-end wrench, press the intake camshaft in the direction indicated by the arrow and secure the chain tensioner with the KM-955-1 device, thereby loosening the chain tension.

Caution: When pressing/turning the camshafts, the key must be installed only on the hexagon-shaped part of the shaft (see illustration 6.14b)!

6.14a Loosening the chain tension (z10XEP engine): 1. Bolt holes for installing the fixing device; 2. Installation of the KM-955-1 device

6.14b. Fastening bolts (2) of camshaft sprockets: 1. Hexagonal part of camshaft

15. Holding the camshafts from turning by the hexagonal part, loosen the sprocket mounting bolts of both shafts (see illustration 6.14b), and then unscrew them one by one and replace them with new ones. Tighten the bolts, but so that the intake camshaft sensor rotor (see illustration 6.12) could be turned manually.

16. Install the KM-953 device, if necessary, tighten the camshafts using an open-end wrench - pay attention to the correct installation of the camshaft cams (see illustration 6.8). Remove the KM-955-1 device.

17. Install the KM-954 device so that the protrusion of the device coincides with the recess of the rotor (see illustration 6.12) - if necessary, tighten the rotor manually.

18. Screw the KM-955-1 tool mounting hole bolt back into place and tighten to the required torque. Tighten the camshaft sprocket mounting bolts to 10 Nm - no more, then remove all adjusting tools.

19. Tighten the sprocket mounting bolts to 50 Nm and another 60° - use an assistant if necessary, then smoothly turn the engine crankshaft 2 full turns and use the tools to check the TDC position - if the tools are not installed (see above), re-adjust the valve timing.

Installation

20. Install all removed components in the reverse order of removal. Use a new cylinder head cover gasket when reassembling (see accompanying illustration), apply a layer of sealant sealant (eg, "Silikon Blau RTV" Loctite) 2 mm thick on the joints of the cylinder head and timing cover.

Caution: The cover must be installed within 10 minutes after applying the sealant! Do not forget to replace the crankshaft locking hole plug gasket.

Engines Z14XE/Z1 6XE/Z18XE

21. Remove the multi-rib belt cover (see Section 5).

22. Remove 3 mounting bolts (see accompanying illustration), separate the upper timing belt cover from the rear timing belt cover and remove it.



23. Turn the crankshaft pulley in the direction of engine rotation (clockwise) so that the marks on the pulley and engine block match (see accompanying illustration) - the marks on the camshaft gears should also match. Now the piston of the first cylinder is at TDC of the compression stroke.

Note: If the camshaft marks are on the outside of the gears, turn the crankshaft one more revolution.

If the timing marks do not match, it is necessary to adjust the timing phases, for which it is necessary to remove the timing belt (see section 8).

24. After completing the check, reinstall the removed components. Installation is performed in the reverse order. Before installing the upper timing belt cover, check its integrity and thoroughly wipe it from the outside and inside.

Z16SE Engine

25. Remove the V-belt cover (see Section 5).

26. Unscrew 3 bolts and remove the upper timing belt cover (see Section 8).

27. Turn the crankshaft pulley in the direction of engine rotation (clockwise) so that the marks on the pulley and the lower timing belt cover match (see accompanying illustration) - the marks on the camshaft gear and the rear timing cover should also match. Now the piston of the first cylinder is at TDC of the compression stroke.

Note: If the camshaft mark is on the underside of the timing gear, turn the crankshaft one more revolution.

If the timing marks do not match, it is necessary to adjust the timing phases, for which it is necessary to remove the timing belt (see Section 8).

Z13DT Engine

28. Remove the multi-rib belt cover, (see Section 5).

29. Remove the fuel distribution line (see Chapter 4).

30. Disconnect the glow plug, injector and camshaft sensor wiring connectors. Remove the 3 cable channel mounting bolts and set it aside.

31. Unscrew 2 plugs from the camshaft housing (see illustration 6.31a). Clean the threads and screw the locking pins into the holes (Opel-EN-46781) (see illustration 6.31b) - after installation, the chamfers on the outer side of the studs should be horizontal. If necessary, mark the studs.

6.31a. Camshaft housing plugs (z13DT engine)

6.31b. Installing the Opel-EN-46781 retaining pins (z13DT engine) - the arrows indicate the position of the bald spots

32. Turn the crankshaft clockwise until the spring-loaded locking pins are engaged.

Caution: When turning the crankshaft, the assistant must ensure that the locking pins do not turn!

33. Insert the Opel-EN-46785 pin into the special hole on the manual transmission (see accompanying illustration), slightly rotating the crankshaft back and forth so that the pin enters the hole in the flywheel. If the pin does not fit into the flywheel, it is necessary to adjust the valve timing.

Engines Y17DT(L)/Z17DTH

Note: The procedure for setting the first cylinder to the TDC position of the compression stroke is described below using the Y17DT engine as an example. When performing this procedure on other engines, some additional steps will be required.

34. Loosen the fastening clamps and remove the flexible hose and the intermediate pipe of the engine air supply system (see Chapter 4).

35. Remove the right front wheel (see Chapter "Introduction"), place the suspended vehicle on stands.

36. Loosen the mounting clamps and remove the lower intermediate pipe of the intake air duct (see Chapter 4).

37. Remove the multi-rib belt (see Section 7).

38. Disconnect the generator wiring (see Chapter 5).

39. Separate the cable tray and vacuum lines from the upper front timing belt cover. Remove the mounting bolts and remove the upper timing belt cover.

Note: The cover is secured with bolts of different lengths, please remember or mark their installation position with a marker.

40. Turn the crankshaft until the holes on the camshaft and fuel injection pump gears are aligned with the holes on the engine body and screw in the mounting bolts (see accompanying illustration) M6 into the corresponding hole of the camshaft wheel and M8 into the fuel injection pump drive wheel. Check the alignment of the marks - with the mounting bolts screwed in, the mark on the crankshaft pulley should match the pin on the oil pump cover.

Note: With the crankshaft pulley removed, the mark on the toothed pulley should align with the lug on the oil pump cover.

If the marks do not match, it is necessary to adjust the timing phases (see Section 8) - remove the timing belt first.