Valvetrain, Servicing

Valvetrain, servicing

Note:
^ Cylinder heads with small cracks between the valve seats that are less than 0.3 mm (0.012 inch) wide and/or between one valve seat and only the first 4 threads of the spark: plug thread, can continue to be used without reduced service life.
^ Always replace gaskets, seals and 0-rings.

CAUTION!
^ After installing the camshafts, the engine must not be started for approximately 30 minutes. The hydraulic valve lifters have to settle (otherwise valves will strike the pistons).
^ After installing the valvetrain and lifters, carefully rotate the crankshaft by hand at least 2 full revolutions before starting to be sure that valves do not strike the pistons.





1 - Bolt
^ 65 Nm (48 ft. lbs.)
^ Use 3036 retainer when loosening or tightening
2 - Camshaft gear
^ For exhaust camshaft
^ Verify correct installation position: thin rib of camshaft gear points forward and TDC Cyl. 1 marking is visible from front
3 - Oil seal
^ For exhaust camshaft
^ Always replace, Refer to Seals and Gaskets, Engine, Camshaft Oil Seal, Service and Repair
4 - Cylinder head
^ Note, Refer to Cylinder Head Removing
^ Check valve guides, reface valve seats, Refer to Valve Seat, Service and Repair
^ Bearing cap bushings must be installed in cylinder head
^ Seal contact surfaces, Refer to Cylinder Head, Removing and Installation, See, Fig. 3 and Fig. 4
^ Reface valve seats, Refer to Valve Seat, Service and Repair
5 - Valve guide
^ Check , Refer to Valve Guide, Testing and Inspection
^ Replace -1- , Refer to Valve Guide, Testing and Inspection, Service and Repair
6 - Valve stem oil seal
^ Replace, Refer to Seals and Gaskets, Engine, Valve Guide, Seal, Service and Repair
7 - Valve spring
^ Removing and installing, Refer to Seals and Gaskets, Engine, Valve Guide, Seal, Service and Repair
8 - Valve spring retainer
9 - Valve keeper
10 - Hydraulic valve lifter
^ Check, Refer to Lifter, Valve, Testing and Inspection
^ Removing and installing, Refer to Seals and Gaskets, Engine, Valve Guide, Seal, Service and Repair
^ Do not interchange
^ When removed, store with contact surfaces facing down
^ Before installing, check axial play in camshafts, Refer to Camshaft, Testing and Inspection
^ Oil contact surface
11 - Intake camshaft
^ Using Plastigage check radial play (valve lifters removed)
Wear range: 0.1 mm (0.004 inch)
^ Maximum runout: 0.01 mm (0.0004 inch)
^ Axial play, checking, Refer to Camshaft, Testing and Inspection
^ Camshafts, removing and installing, Refer to Camshaft, Service and Repair
12 - Bearing cap for intake camshaft
^ Must fit on bushing
^ Bushings must be installed in cylinder head
^ Verify correct installation position
^ Installation sequence, Refer to Camshaft, Engine, Service and Repair
13 - Double bearing cap
^ Must fit on bushing
^ Bushings must be installed in cylinder head
^ Before installing, seal contact surfaces lightly with sealant D 454300 A2 , Refer to Valve, Intake/Exhaust, Service and Repair
Sealing contact surfaces between double bearing cap and cylinder head, Refer to Cylinder Head Removing and Installing, See, Fig 3
14 - Exhaust camshaft
^ Using Plastigage check radial play (valve lifters removed)
Wear range: 0.1 mm (0.004 inch)
^ Maximum runout: 0.01 mm (0.0004 inch)
^ Axial play, checking, Refer to Camshaft, Engine, Testing and Inspection
^ Camshafts, removing and installing, Refer to Camshaft, Service and Repair
15 - Bearing cap for exhaust camshaft
^ Must fit on bushing
^ Bushings must be installed in cylinder head
^ Verify correct installation position
16 - Bolt
^ 10 Nm (7 ft. lbs.)
17 - Bolt
^ 10 Nm (7 ft. lbs.)
18 - Drive chain
^ Check for wear
^ Before removing, mark installed position
^ Camshafts, removing and installing, Refer to Camshaft, Engine, Service and Repair
19 - Hydraulic chain tensioner
^ Before removing, secure with VAG3366 chain tensioner bracket
^ Seal contact surfaces between hydraulic chain tensioner and cylinder head, Refer to Cylinder Head Removing and Installing, See Fig. 4
20 - Rubber/metal - seal
21 - Gasket
^ Always replace
22 - Exhaust valve
^ Sodium filled
^ Follow disposal procedures for sodium filled valves, Refer to Intake/Exhaust, Valve, Service and Repair
^ Do not reface by grinding, only hand lapping is permitted
^ Valve dimensions, Refer to Intake/Exhaust, Valve, Service and Repair, See Fig. 1
^ Checking valve guides, Refer to Valve Guide, Checking
^ Refacing valve seats, Refer to Valve Seat, Service and Repair
23 - Intake valve
^ Do not reface by grinding; only hand lapping is allowed
^ Valve dimensions, Refer to Intake/Exhaust, Valve, Service and Repair, See Fig. 1
^ Checking valve guides, Refer to Valve Guides Testing and Inspecting
^ Refacing valve seats, Refer to Valve Seat, Service and Repair
24 - Oil seal
^ For intake camshaft
^ Replacing, Refer to Seals and Gaskets, Engine, Camshaft Oil Seal, Service and Repair
25 - Shutter wheel for Camshaft Position (CMP) sensor -G40-
^ Note position: insert lug in camshaft notch
26 - Washer
^ Conical
^ Note position
27 - Bolt
^ 25 Nm (18 ft. lbs.)
28 - Camshaft Position (CMP) sensor -G40- housing
29 - Bolt
^ 10 Nm (7 ft. lbs.)





Fig. 1 Valve dimensions

WARNING!

^ Valves must not be refaced by cutting or grinding.
^ Only hand lapping is permitted.








WARNING!
^ Sodium-filled exhaust valves must not be scrapped without first being properly treated.
^ The valves must be cut open using a hacksaw, by hand, between the valve head and the middle of the stem.
^ The valves must not come into any contact with water while being cut.
^ After cutting open the valves, throw not more than 10 at a time into a bucket of water and step back. A sudden chemical reaction will occur during which the sodium filling is consumed.
^ Valves that have been treated in this way can be disposed of as normal waste.