TDC position of the piston of the 1st cylinder of the DOHC engine
The position of the set marks on the camshaft sprockets corresponding to the TDC of the piston of the 1st cylinder of the DOHC engine is indicated by arrows.
DOHC Timing Chain Hydraulic Tensioner
A - the piston is blocked (two positions are possible), B - piston is partially blocked, C - piston is unlocked, 1 - ring
The drive chain of the gas distribution system
During all operations that require the removal of the camshaft drive chain, the hydraulic chain tensioner must be replaced before it is reinstalled.
Changed the chain replacement method. You should proceed as follows.
Timing chain replacement
1. Disconnect ground wire from battery.
2. Disconnect the air damper together with the flexible air supply pipe, idle control valve and crankcase ventilation pipe.
3. Disconnect the crankcase breather pipe from the cylinder head cover.
4. Disconnect the wire from the ignition coil to the ignition distributor.
5. Remove distributor cap (two bolts with Torx socket).
6. Disconnect the high voltage wires, remove the distributor rotor and remove the protective plate of the ignition distributor.
7. Remove the cylinder head cover.
8. Remove upper timing chain cover.
9. Turn the crankshaft so that the piston of the 1st cylinder is at TDC (see fig. TDC position of the piston of the 1st cylinder of the DOHC engine).
10. Block the camshaft sprockets using a special wrench and unscrew the fastening bolts with a Torx socket.
11. Remove the plastic chain guide after removing the two blocking elements with tweezers.
12. Remove the distributor drive.
13. Mark the position of the chain in relation to the sprockets of both camshafts.
14. Remove the sprockets from both camshafts and lightly tighten the chain on the left side.
15. Remove the spring adjusting ring of the tensioner shaft.
16. Using the M6 bolt, remove the tensioner axle while moving the tensioner down to loosen the chain tension (see fig. Removing the axis of the tensioner of the cardan chain of the DOHC engine gas distribution system).
17. Remove tensioner.
18. Remove the tensioner hydraulic tappet.
Attention! The pusher cannot be reinstalled.
19. Install a new hydraulic tappet. Check if it's blocked properly (see fig. DOHC Timing Chain Hydraulic Tensioner). If it's fully unlocked (visible ring 1) or partially unlocked (the entire upper part of the pusher piston is visible), then to block, press the piston into the pusher cylinder (the top of the piston is not visible or protrudes minimally from the cylinder). Care must be taken not to damage the hydraulic tappet pistons.
20. Insert the entire assembly into the cylinder head (the piston must be pointing up).
21. Install tensioner, axle and circlip.
22. Fit the chain to the left camshaft sprocket. Set the shaft to the position corresponding to the position of the piston of the 1st cylinder at TDC, and screw the sprocket mounting bolt by hand.
23. Carry out the same operations for the right camshaft and install the ignition distributor drive.
24. Install new chain guide (made of artificial material) and fix it.
25. Slowly turn the crankshaft clockwise until the intake camshaft begins to rotate.
26. If the piston of the pusher protrudes from its cylinder, then you should press the tensioner by hand to unlock the pusher.
27. If the top edge of the piston is at the height of the top edge of its cylinder (blocked), then to unlock the piston, proceed as follows: lift the tensioner with a screwdriver and place, for example, a welding electrode between the housing and the piston. Then remove the screwdriver and unlock the piston.
28. Block the camshaft sprockets and tighten their bolts to 56–62 Nm.
29. Rotate the crankshaft a few times and check tensioner adjustment.
30. Check the condition of the gasket and put on the upper casing of the drive chain of the timing system.
31. Carry out the rest of the steps in reverse order with respect to the process of removing the chain.
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