DOHC Engine Timing System (Sierra)

Valve timing system DOHC

Removal the drive chain tensioner axle of the DOHC engine timing system

Removing the retaining ring.



Removing the tensioner axle.

Location of the hydraulic tappet of the tensioner of the drive chain of the DOHC engine timing system

Installing the valve timing of a DOHC engine

Camshaft installation marks.



Crankshaft timing marks.

Replacement of the cardan chain of the gas distribution system

1. Disconnect the ground wire from the battery.



2. Remove the V-belt from the generator and coolant pump drive.

3. In a carburetor engine, remove the air filter.

4. In the fuel injection version, remove the air supply line from the filter to the throttle body.

5. Remove the high-voltage wires, unscrew the spark plugs, distributor cap and distributor rotor.

6. Disconnect the crankcase ventilation pipe from the cylinder head cover.

7. Disconnect the accelerator pedal cable. In a carburetor engine, unscrew the throttle cable together with the holder, and in a fuel-injected engine, disconnect the rod from the throttle body after removing it from the side of the clamp made of artificial material.

8. Remove the cylinder head cover (11 bolts and 4 nuts).

9. Remove the ignition distributor.

10. Remove the upper cover of the cardan shaft of the timing chain.

11. Set the piston in cylinder N1 to TDC.

Attention! You can turn the crankshaft with a spanner by the middle bolt of the sprocket fastening in the direction of its working rotation until the marks on the camshaft sprockets are set at the height of the upper plane of the cylinder head and are directed outward in both camshafts.

12. Unscrew the crankshaft sprocket mounting nut.

13. Using a puller, remove the sprocket from the crankshaft. If necessary, remove the radiator as well.

14. Remove the lower cover of the cardan shaft of the timing chain.

15. Remove the oil pump cardan chain tensioner.

16. Unscrew the Torx socket bolt securing the oil pump drive sprocket and remove the sprocket together with the chain.



17. Remove the upper guide of the cardan chain of the gas distribution system, held by the spring catch.

18. Unscrew the upper and lower bolts of the side guide of the cardan chain of the gas distribution system.

19. Remove the tensioner retaining ring, then remove the timing chain tensioner.

20. Remove the chain tensioner axle using a M6Ch70 bolt and a 15 mm long sleeve.

21. Remove the sprockets from both camshafts. Mark them so that they can be put in the correct places during assembly.

22. Pull the side chain guide upward.

23. Remove the sprocket from the crankshaft.

24. Remove the timing chain upwards.

25. Remove the chain tensioner.

26. Remove the hydraulic chain tensioner pusher.

Caution! After removing the drive chain, do not turn the crankshaft.

27. Disassemble the hydraulic tensioner pusher and drain the oil.

28. Using special tool 21.145, assemble the hydraulic pusher of the tensioner, filled with engine oil. To do this, install the pusher body with the flat side on the workbench, and the sleeve of the tool with the cone facing up. Install the piston of the pusher on the sleeve and squeeze everything together with the lever of the tool, which makes a characteristic sound after pressing to the stop (in the lowest position).

29. Check if the piston of the 1st cylinder is at TDC (the crankshaft groove is pointing down).

30. Place the chain on the crankshaft. Check that it is connected to the crankshaft correctly.

31. Install the side chain guide.

32. Install the hydraulic chain tensioner pusher.



33. Install the chain tensioner.

34. Insert the chain tensioner together with the snap ring.

35. Set the camshafts to the position shown in Fig. Setting the valve timing of a DOHC engine – the keyways of both shafts should be directed horizontally outward from the cylinder head.

36. Place the timing chain onto the camshaft sprockets.

37. Install the sprockets together with the chain on the camshafts so that the marked chain link is located opposite the mark on the crankshaft sprocket (see the bottom of the figure. Installing the valve timing of the DOHC engine).

Caution: When installing the sprockets, the drive chain must be tensioned on the opposite side of the tensioner.

38. Place the ignition distributor drive elements on the front end of the intake camshaft.

39. Turn the crankshaft several revolutions (in the working direction).

40. Set the piston in cylinder N1 to TDC and check whether the keyways of the camshaft sprockets are installed horizontally outside the cylinder head (Fig. Installing the valve timing of a DOHC engine).

41. Install the upper chain guide.

42. Place the oil pump drive chain on the sprocket on the crankshaft, and then install the sprocket (with the chain on it) on the oil pump shaft, making sure that the "FRONT" inscription on the sprocket is on the outside (visible).

43. Install the oil pump cardan chain tensioner.

44. Set the sprocket groove to match the crankshaft groove.

45. Install the lower cover of the cardan shaft of the timing chain together with a new gasket, screw in the bolts of its fastening, but do not tighten them.



46. Place the pulley on the crankshaft and tighten its mounting nut to the appropriate torque.

47. Tighten the lower driveshaft chain cover mounting bolts to the appropriate torque.

48. Perform further actions in reverse order to the removal process, paying attention to:

• installation of a new gasket for the upper casing of the cardan chain of the timing system;
• the correct sequence for tightening the cylinder head cover bolts, starting with the outer ones and ending with the middle ones;
• compliance with the required tightening torques of the corresponding threaded connections;
• filling with liquid and bleeding air from the engine cooling system after installation is complete;
• checking the engine idle speed control parameters.

A copy of the article is available on the website [fordbook.ru]