Adjusting the valve timing
1 - crankshaft sprocket; 2 - camshaft sprocket; 3 - intermediate shaft sprocket; 4 - chain tensioner shoe
Details of the valve timing mechanism of 4-cylinder engines
1 - crankshaft; 2 - crankshaft sprocket; 3 - distribution chain; 4 - intermediate shaft of the fuel pump drive and ignition distributor sensor; 5 - camshaft sprocket; 6 - chain tensioner; 7 - tensioner shoe; 8 - chain tensioners; 9 - camshaft; 10 - rocker arm; 11 - rocker axis; 12 - valve guide bushing; 13 - valves; 14 - spring; 15 - spring plate; 16 - crackers; 17 - pusher; 18 - adjusting bolt
Sectional view of crankshaft pulley and sprocket
1 - crankshaft; 2 - mounting key; 3 - crankshaft sprocket; 4 - oil pump drive spacer; 5 - oil seal cage; 6 - oil seal; 7 - camshaft drive cover; 7 - camshaft drive cover; 8 - key; 9 - pulley hub; 10 - disc washer; 11 - mounting bolt; 12 - pulley to hub mounting bolt
Replacing the camshaft drive chain
The chain can be replaced from above the engine. However, when replacing the chain, it is recommended to remove the timing cover, check the condition of the dampers, shoe and tensioner of the chain and sprockets.
Removal the chain
Timing marks on the camshaft. The arrow shows the alignment of the mark with the plane of the cylinder head
1. Place the hood in a vertical position.
2. Drain the oil from the engine.
3. Drain the coolant.
4. Disconnect the ground wire from the battery.
5. Remove the air filter.
6. Remove the radiator.
7. Remove the fan.
8. Depending on the year of manufacture of the vehicle, loosen and remove the alternator drive belt or the multi-groove accessory drive belt.
9. Remove the water pump.
10. Remove the auxiliary units from the camshaft drive cover (air conditioning compressor, power steering pump, generator) and hang them in the engine compartment, being careful not to disconnect the hoses.
11. Remove the TDC sensor.
12. Remove the engine splash guard.
13. Unscrew the bolts securing the anti-roll bar to the body.
14. Depending on the configuration, remove the front bumper.
15. Disconnect the bracket securing the exhaust pipe to the gearbox and separate the pipe and the exhaust manifold.
16. Loosen the bolts securing the gearbox support to the cross beam.
17. Loosen the engine crankcase mounting bolts.
18. Loosen the bolts securing the engine bracket to the cross beam.
19. Support the engine with a hoist chain and lift it up to remove the crankcase.
20. Remove the oil receiver and oil intake pipe bracket.
21. Remove the cylinder head cover.
22. Remove the four bolts securing the camshaft drive cover to the cylinder head.
23. Remove the ignition distributor sensor.
24. Press the dowel pins into the cylinder block.
25. Loosen the bolts securing the cover to the cylinder block, lower the cover to separate the cylinder head gasket (try not to damage the gasket) and take it off.
26. Turn the crankshaft until the piston of the 1st cylinder reaches TDC, which corresponds to the combustion phase (mark on the front camshaft bearing).
27. Remove the chain tensioner pusher.
28. Remove the guides, shoe and chain tensioner.
Information copied from the website MERCEDESMAN.ru
29. Remove one of the chain links by cutting its axles with an abrasive wheel.
30. Remove the chain from the sprockets.
31. Check the condition of the sprockets, guides, and chain tensioner.
Installing the chain
Installing the chain guide
Installing an offset key on the camshaft sprocket to compensate for chain stretching
Location of the centering pins of the camshaft drive cover on the cylinder block
Removing the camshaft drive sprocket
When installing the crankshaft pulley, direct the convex part of the three disc washers toward the pulley
1. Check the position of the piston of the 1st cylinder at TDC and the position of the camshaft.
2. Place the new chain onto the sprockets with the quick connect link retaining washers facing the camshaft cover.
3. Install the chain guides, shoe and chain tensioner push piston.
A slight offset of the camshaft relative to the crankshaft can be eliminated by installing an offset key on the camshaft drive sprocket.
4. Check the condition of the oil pump and replace the seals.
5. Cut the paper gasket of the camshaft drive cover at the break points.
6. Lubricate the gasket with special glue and put it in place.
7. Remove the centering pins from the cylinder block.
8. Install the camshaft drive cover, tighten the bolts, paying attention to their length and avoiding damage to the cylinder head gasket.
9. Gradually tighten the cover mounting bolts.
10. Install the crankshaft oil seal housing (when replacing the seal, replace the collar as well).
11. Install the crankshaft pulley and tighten the bolts to the specified torque.
12. Secure the oil receiver and oil intake pipe bracket to the crankshaft main bearing.
13. Install a new engine crankcase gasket.
14. Install the engine crankcase.
15. Install the engine on the supports, tighten the bolts securing the engine and gearbox mount brackets.
16. Connect the exhaust pipe to the exhaust manifold, secure the exhaust pipe bracket to the gearbox.
17. Install the buffer.
18. Install the anti-roll bar.
19. Install the engine shield.
20. Install the TDC sensor.
21. Install the air conditioning compressor, power steering pump and generator.
22. Install the water pump with a new gasket.
23. Depending on the year of vehicle production, install the alternator drive belt or the accessory drive belt and adjust its tension.
24. Install the fan and radiator.
25. Connect the hoses and fill with coolant.
26. Remove air from the cooling system.
27. Turn the crankshaft two revolutions to bring the piston of the 1st cylinder to TDC.
28. Make sure that the mark on the camshaft is opposite the plane of the cylinder head.
29. Install the cylinder head cover and fill with oil.
30. Install the ignition distributor sensor.
31. Check the engine idle speed, ignition timing and ensure there are no oil or coolant leaks.