Valve Train, Servicing

Valve train, servicing

Note:
^ Cylinder heads which have cracks between the valve seats or between valve seat inserts and the spark plug thread can continue to be used without reducing service life provided the cracks do not exceed a maximum of O.3 mm in width, or when no more than the first four spark plug threads are cracked.
^ After installing new hydraulic lifters, do NOT start the engine for approximately 30 minutes or the valves will strike the pistons. After 30 minutes manually turn the crankshaft two rotations before starting.

1. 100 Nm (74 ft. lbs.)
^ Use 3415 counter-hold to loosen and tighten
2. Camshaft sprocket
3. Oil seal
^ Replacing, Refer to Seals and Gaskets, Engine, Camshaft Oil Seal, Service and Repair
4. Woodruff key
^ Ensure tight fit
5. 20 Nm (15 ft. lbs.)
6. Bearing cap
^ Installation position Fig 3
^ Installation sequence, Refer to Camshaft Engine, Service and Repair
^ Lightly coat bearing cap 1 contact surfaces with D 454300 A2 sealant
7. Camshaft
^ Axial clearance, checking, Refer to Fig. 2
^ Removing and installing, Refer to Camshaft, Service and Repair
^ Radial clearance, checking with Plastigage: Wear limit: 0.1 mm
^ Run-out: max. 0.01 mm
^ Identification and valve timing
8. Hydraulic lifter
^ Do not interchange
^ With hydraulic valve clearance compensation
^ Checking, Refer to Lifter Valve, Testing and Inspection
^ Store with cam contact surface facing downward
^ Check camshaft axial clearance before installing, Refer to Fig. 2
^ Oil contact surfaces
9. Keepers
10. Valve spring retainer, upper
11. Valve spring
^ Removing and installing:
- Cylinder head removed: using tool 2037
- Cylinder head installed, Refer to Seals and Gaskets, Engine, Valve Guide Seal, Service and Repair
12. Valve stem seal
^ Replacing, Refer to Seals and Gaskets, Engine, Valve Guide Seal, Service and Repair
13. Valve guide
^ Checking, Refer to Valve Guide, Testing and Inspection
^ Replacing, Refer to Valve Guide, Service and Repair
^ Service version with collar
14. Cylinder head
^ Sealing surface, reworking
^ Servicing notes, Refer to Cylinder Head, Service and Repair, Valve Train, Servicing
^ Valve seats, reworking, Refer to Valve Seat, Service and Repair
15. Intake and exhaust valves
^ Do not rework! Only lapping is permitted
^ Valve dimensions, Refer to Fig. 4





Fig. 1 Cylinder head sealing surface, reworking
^ Cylinder head reworking dimension: a = 132 6 mm minimum

Note: When the sealing surface has been reworked, the valves must be set deeper by the same amount (rework valve seat inserts), otherwise the valves will contact the pistons. Ensure that the minimum permissible dimension is maintained while doing this, Refer to Valve Seat, Service and Repair.





Fig. 2 Camshaft axial clearance, checking

Special tools and equipment
^ VW 387 Universal dial gauge bracket
^ Dial indicator

Note:
^ Check with hydraulic lifters removed and with first and last bearing caps installed.
^ Wear limit: max. 0.15 mm





Fig. 3 Camshaft bearing caps, installed position
Note offset. Before installing camshaft; install bearing caps to determine correct installed position.





Fig. 4 Valves, dimensions

Note: Do NOT re-work the valves! Only lapping is permitted.





Engine Code AEG





Engine Code AVH, AZG





Fig. 5 Camshaft identification, valve timing





Identification
^ Cam base diameter: a = 34 mm diameter
^ Identification by stamped numbers and letters between intake and exhaust lobes:





Valve timing at 1 mm valve lift