Valve Gear, Servicing

Valve gear, servicing

CAUTION!
^ DO NOT re-use fasteners that are worn or deformed in normal use.
^ Some fasteners are designed to be used only once and are unreliable and may fail the second time. This includes, but is not limited to nuts, bolts, washers, circlips and coffer pins. Always follow the recommendations in this manual - replace these fasteners with new parts where indicated and any other time when deemed necessary by inspection.

CAUTION! After working on valves, do not start the engine for about 30 minutes, otherwise the valves will strike pistons. Turn the crankshaft two complete revolutions by hand before starting engine.

Note: Cylinder heads with cracks between valve seats or between valve seat inserts and spark plug threads can continue to be used without reduced service life, if the cracks are not wider than 0. 3 mm (O.012 inch) or when no more than 4 turns of the spark plug threads are cracked.





1 Double bearing cap
^ Lightly coat with sealant AMV 188 02 Fig. 2
2 10 Nm (7 ft. lbs.)
3 Hydraulic valve lifter
^ Do not interchange.
^ Lubricate contact surface with oil.
4 Exhaust camshaft
^ Check axial play
^ Check radial clearance using Plastigage (lever removed):
Wear limit: 0.1 mm (0.0039 inch)
Maximum run-out: 0.01 mm (0.0004 inch)
5 Intake camshaft bearing cap
^ Observe dowel pin.
6 Exhaust camshaft bearing cap
Observe dowel pin.
7 10 Nm (7 ft. lbs.)
8 Double bearing cap
9 Cap
^ Always replace
^ To remove: remove bearing cap.
^ With cap installed, lightly drive in with 3202
10 Bearing cap
^ Before installing lightly coat with sealer AMV 188 02 Fig. 2

CAUTION! Part numbers are listed for reference only. Always check with your Parts department for latest information.

11 Valve roller lever for exhaust camshaft
12 Drive chain
13 Valve roller lever for intake camshaft
14 Intake camshaft
^ Check radial clearance using Plastigage (lever removed):
^ Wear limit: 0.1 mm (0.0039 inch)
^ Maximum runout: 0.01 mm (0.0004 inch)
^ 15 - 10 Nm (7 ft. lbs.)
16 Mechanical camshaft adjuster
^ With valve for camshaft adjustment -N205
^ Before removing, secure with 3366 bracket tensioner.
17 Rubber/metal - seal
^ Always replace.
18 Valve keepers
19 Valve spring plate
20 Valve spring
21 Valve stem seal
^ Replacing, refer to Valve Seal.
22 Seal
^ Always replace
23 Cylinder head
^ See note, Refer to Cylinder Head.
^ Valve guides, checking, Refer to Valve Guides.
^ Valve seats, reworking, refer to Valve Seats.
24 Exhaust valve
^ Do not rework, only lapping is permitted
^ Valve dimensions Fig. 1.
^ Valve guides, checking, valve seats lapping, Refer to Valve, Intake/ Exhaust.
25 Intake valve
^ Do not rework, only lapping is permitted
^ Valve dimensions Fig. 1.
^ Valve guides, checking, valve seats lapping, Refer to Valve, Intake/ Exhaust.
26 Seal
^ For intake camshaft
^ Removing and installing, refer to Camshaft, Lifters and Push Rods.
27 - 28 Rotor for Camshaft Position (CMP) sensor
^ Note position
29 Washer
^ Conical
30 23 Nm (17 ft. lbs.)
31 Camshaft Position (CMP) sensor
32 5 Nm (44 inch lbs.) + 90°
33 Shaft for valve roller lever, intake side
34 9 Nm (80 inch lbs.)
35 9 Nm (80 inch lbs.)
36 Shaft for valve roller lever, exhaust side
37 55 Nm (41 ft. lbs.)
38 Camshaft sprocket
39 Seal
^ For exhaust camshaft
^ Removing and installing, Refer to Camshaft, Lifters and Push Rods.





Fig. 1 Valve dimensions

Note: Do not reface valves. Only hand-lapping is permissible.








WARNING! Sodium-filled exhaust valves must not be scrapped until they have been properly treated as follows:
^ Saw valves in two sections using metal saw at a point between the center of the valve stem and the valve head. The valves must not come into contact with water when this is done.
^ Throw the valves into a bucket of water (not more than 10 at a time) and step back. A sudden chemical reaction will occur during which the sodium filling burns. After this treatment the valves can be scrapped normally.





Fig. 2 Bearing cap, applying sealer
^ Coat gray surfaces of front and rear bearing caps for intake camshaft lightly with sealant AMV 188 02. Install bearing caps, observe dowel pins.

CAUTION! Part numbers are listed for reference only. Always check with your Parts department for the latest information.