Valve Gear, Servicing
Valve gear, servicing
Note:
^ Cylinder heads which have cracks between valve seats or between valve seat inserts and the spark plug thread can be used further without reducing service life, provided cracks do not exceed a max. of 0.3 mm in width, or when no more than first 4 turns of spark plug threads are cracked.
^ After installing camshafts, engine must not be started for approx. 30 minutes. Hydraulic valve compensation elements have to settle (otherwise valves will strike pistons).
^ After working on valve gear, turn engine carefully at least 2 rotations to ensure that none of the valves make contact when starter is operated.
^ Always replace gaskets and sealing rings.
1 - 65 Nm
^ Use counterhold 3036 to loosen and tighten
2 - Camshaft sprocket
^ For exhaust camshaft
^ Note installed position: Narrow web of camshaft sprocket must face toward front and marking for TDC No. 1 cylinder must be visible from front
3 - Oil seal
^ For exhaust camshaft
4 - Cylinder head
^ See note
^ Dowel sleeves for bearing caps must be located in cylinder head
^ Sealing transition points and
5 - Valve guide
6 - Valve stem seal
7 - Valve spring
8 - Valve spring plate
9 - Valve keeper
10 - Hydraulic valve lifter
^ Do not interchange
^ Store with contact surface downward
^ Before installing check camshaft axial clearance
^ Oil contact surface
11 - Intake camshaft
^ Check radial clearance with Plastigage (TM) (valve lifters not installed), Wear limit: 0.1 mm; Run-out: max. 0.035 mm
12 - Bearing cap for intake camshaft
^ Must be located on dowel sleeves
^ Dowel sleeves must be located in cylinder head
^ Note installed position
^ Installation sequence
13 - Double bearing cap
^ Must be located on dowel sleeves
^ Dowel sleeves must be located in cylinder head
^ Apply small amount of AMV 188 001 02 to sealing surface before installation
^ Sealing transition points between double bearing cap and cylinder head
14 - Exhaust camshaft
^ Check radial clearance with Plastigage (TM) (valve lifters not installed): Wear limit: 0.1 mm; Run-out: max. 0.035 mm
15 - Bearing cap for exhaust camshaft
^ Must be located on dowel sleeves
^ Dowel sleeves must be located in cylinder head
^ Note installed position
^ Installation sequence
16 - 10 Nm
17 - 10 Nm
18 - Drive chain
^ Check for wear
^ Mark position of chain before removing
19 - Camshaft adjuster
^ With Valve 1 for camshaft adjustment N205
^ Secure with retainer for chain tensioner 3366 before removing
^ Sealing transition points between camshaft adjuster and cylinder head
20 - Rubber/metal gasket
^ Apply sealant AMV 188 001 022 before installation
21 - Gasket
^ Replace
22 - Exhaust valve
^ With sodium filling
^ Note instructions on scrapping valves with sodium filling
^ Do not rework, only lapping is permitted
^ Valve dimensions
23 - Intake valve
^ Do not rework, only lapping is permitted
^ Valve dimensions
24 - Oil seal
^ For intake camshaft
25 - Camshaft position sensor rotor ring
^ Note installed position: locate lug in notch on camshaft
26 - Washer
^ Conical
^ Note installed position
27 - 25 Nm
28 - Housing for Camshaft Position (CMP) sensor G40
29 - 10 Nm
Valve dimensions
Note:
^ Intake and exhaust valves must not be reworked. Only lapping is permitted.
CAUTION: Worn exhaust valves with sodium filling must not be scrapped in the usual way.
The valves must be cut into two pieces between the shaft center and the valve head using a metal saw. When doing this they must not come into contact with water. Throw a maximum of ten valves prepared in this way into a bucket of water. Then step backward because a sudden chemical reaction occurs during which the sodium filling is burned.
Parts treated in this way can be scrapped in the usual manner.