Camshaft, Lifters and Push Rods: Service and Repair
Valve gear, assembly overview
Note:
Cylinder heads which have cracks between the valve seats or between valve seat inserts and the spark plug thread can be used further without reducing service life, provided the cracks do not exceed a maximum of 0.3 mm in width, or when no more than the first four spark plug threads are cracked.
After installing new hydraulic lifters, the engine must not be started for approximately 30 minutes (otherwise valves will strike pistons), then turn crankshaft two rotations.
1. 10 Nm
2. Intake camshaft
Checking axial clearance, Refer to Fig. 2
Checking radial clearance with plastigage:
Wear limit: 0.1 mm
Run-out: max. 0.035 mm
3. Drive chain
Before removing mark direction of rotation (installation position), Refer to Camshaft, Engine, Service and Repair, Camshaft, removing and installing
4. 10 Nm
5. O-ring
Engines with camshaft timing adjustment only
Always replace
6. Valve 1 for Camshaft adjustment -N205-
Engines with camshaft timing adjustment only
7. 3 Nm
Engines with camshaft timing adjustment only
8. Camshaft adjuster
Engines with camshaft timing adjustment only
Engines without camshaft timing adjustment chain tensioner installed
Secure with 3366 before removing
9. Gasket
Rubber/metal seal
Replace
10. Cylinder head
Removing and installing, Refer to Cylinder Head, Service and Repair, Cylinder head, removing and installing
Refacing valve seats, Refer to Valve Seat, Service and Repair
Reworking sealing surface
Sealing transition points, Refer to Fig .4 and
11. Valves
Do not rework only lapping-in is permitted
Valve dimensions, Refer to Fig .3
12. Oil seal
For intake camshaft
Replacing, Refer to Seals and Gaskets, Engine, Camshaft Oil Seal, Service and Repair
Do not oil sealing lip of PTFE seal
13. Hood
For Camshaft Position (CMP) sensor
When installing note fixing arrangement
14. Washer
Conical
15. 25 Nm
16. Camshaft Position (CMP) sensor -G40-
17. 10 Nm
18. 65 Nm
Use counter-hold 3036 to loosen and tighten
19. Camshaft pulley
Note installation position: small web of camshaft sprocket points outward and No. 1 Cyl. TDC marking is visible
20. Oil seal
Replacing, Refer to Seals and Gaskets, Engine, Camshaft Oil Seal, Service and Repair
21. Valve guide
Checking, Refer to Valve Guide, Testing and Inspection
22. Valve stem seal
Replacing, Refer to Seals and Gaskets, Engine, Valve Guide Seal, Service and Repair
23. Valve spring
Removing and installing: remove cylinder head with 3362
Installing, Refer to Seals and Gaskets, Engine, Valve Guide Seal, Service and Repair
24. Upper valve spring plate
25. Valve keepers
26. Hydraulic lifter
Do not interchange
With hydraulic valve clearance compensation
Checking, Refer to Lifter Valve, Testing and Inspection
Store with cam contact surface downward
Before installing check camshaft axial clearance
Oil contact surface
27. Intake camshaft bearing cap
Installation position and installation sequence, Refer to Camshaft, Engine, Service and Repair, Camshaft, removing and installing
28. Double bearing cap
Lightly coat bearing cap contact surface with sealant AMV 174 004 01
Must sit on alignment bushing
Seal transitions of double-bearing cap/cylinder head, Refer to Fig. 4.
29. Exhaust camshaft bearing cap
Installation position and installation sequence,
30. Exhaust camshaft
Checking axial clearance
Removing and installing, Refer to Camshaft Engine, Service and Repair
Checking radial clearance with plastigage:
Wear limit: 0.1 mm
Run-out: max: 0.01 mm
Fig. 1 Reworking cylinder head sealing surface
The dimension for reworking is measured through the holes for the cylinder head bolts.
-a- = minimum 139.2 mm
Fig. 2 Checking camshaft axial clearance
Special tools and equipment
^ Universal dial indicator bracket VW387
^ Dial indicator
Check with hydraulic lifters and chain removed and No. 2 and 4 bearing caps installed.
Wear limit: max. 0.2 mm
Fig. 3 Valve dimensions
Note: Valves must not be reworked. Only lapping-in is permitted.
Note: Care must be taken when disposing of old sodium filled valves. They must be cut through in the center of the stem with a hacksaw. When doing this they must be perfectly dry. The valves prepared in this way can then be thrown into a bucket of water a maximum of ten at a time. When doing this step back quickly because a sudden chemical reaction causes the sodium filling to burn. After this treatment, the valves can be put in with the normal scrap.
Fig. 4 Sealing transition points between double bearing cap and cylinder head
Carefully apply a thin coat of sealant D 454 300 A2 to both edges of sealing surfaces between double bearing cap and cylinder head -arrows- using a small screwdriver.
Fig. 5 Sealing transition points between chain tensioner/cylinder head
Carefully apply a thin coat of sealant "D 454 300 A2" to both edges of sealing surfaces between camshaft adjuster and cylinder head -arrows using a small screwdriver.