Camshaft, Lifters and Push Rods: Service and Repair

Valve gear, servicing






Note:
^ Cylinder heads which have cracks between valve seats or between valve seat inserts and spark plug thread can be used further without reducing service life, provided cracks do not exceed a maximum of 0.3 mm in width, or when no more than first 4 turns of spark plug threads are cracked.
^ After installing camshafts wait for approximately 30 minutes before starting engine. Hydraulic valve compensation elements have to settle (otherwise valves will strike pistons).
^ After working on valve gear, turn engine carefully at least 2 full rotations by hand to ensure that none of the valves make contact when starter is operated.
^ Replace all seals, gaskets and O-rings.

1 - Double bearing cap
^ Lightly coat contact surfaces of front and rear bearing caps with sealant before installation, Refer to Figure 2
^ Liquid sealant:, Refer to Parts Supplier
2 - 5 Nm plus an additional 90° (1/4 turn)
4 - Always replace
3 - Hydraulic valve lifter
4 - Exhaust camshaft
5 - Intake camshaft bearing cap
^ Watch position of dowel sleeve (if fitted)
6 - Exhaust camshaft bearing cap
^ Watch position of dowel sleeve (if fitted)
7 - 5 Nm plus an additional 90° (1/4 turn)
^ Always replace
8 - Double bearing cap
9 - Sealing cap
^ Always replace
^ To remove, pierce through with screwdriver and pry out
^ To install, drive in using 3202 or suitable metal bar or lever
10 - Bearing cap
^ Lightly coat contact surfaces of front and rear bearing caps with sealant before installation, Refer to Figure 2
11 - Valve roller lever for exhaust camshaft
12 - Drive chain
13 - Valve roller lever for exhaust camshaft
14 - Intake camshaft
^ Check radial clearance with Plastigage (roller rocker fingers removed) Wear limit: 0.1 mm. Run-out: 0.01 mm (maximum)
15 - 5 Nm plus an additional 90° (1/4 turn)
16 - Mechanical camshaft adjuster
17 - Rubber/metal seal
18 - Valve keepers
19 - Upper valve spring plate
20 - Valve spring
21 - Valve stem seal
22 - Gasket
^ Always replace
23 - Cylinder head
24 - Exhaust valve
25 - Intake valve
26 - Oil seal
27 - Hall sender rotor
^ Note position (notch on camshaft)
28 - Washer
^ Conical
29 - 23 Nm
30 - Hall sender
31 - 10 Nm
32 - Shaft for roller lever, intake side
33 - 10 Nm
34 - 10 Nm
35 - Shaft for roller lever, exhaust side
36 - 55 Nm
37 - Camshaft sprocket
39 - O-ring
^ For shaft for roller lever
^ Always replace





Figure 1 Valve dimensions





Note: Valves must not be reworked. Only lapping is permitted.

CAUTION:
^ Worn exhaust valves with sodium filling must not be disposed of until they have been treated as follows:
^ The valves must be sawn into two sections with a metal saw at a point between center of shaft and valve head. They must not come into contact with water when this is done. Then throw valves into a bucket of water (not more than ten at time). Then step back because a chemical reaction occurs when sodium filling bums.
^ After this treatment valves can be disposed of in normal way.





Figure 2 Applying sealant to bearing cap
- Apply a thin coat of sealant to shaded areas on double bearing cap and on outer bearing cap next to camshaft adjuster, and install bearing caps (watch position of dowel sleeves).
^ Sealant: See parts catalog.