Valvetrain Assembly Overview
Valvetrain, Assembly Overview
Risk of damaging valves and piston heads after working on valvetrain.
• The motor must not be started for about 30 minutes after installing camshafts because the hydraulic equalization elements must seat themselves.
• To ensure valves do not strike pistons when starting, carefully rotate engine at least 2 full revolutions.
1 Mounting pins or input shaft
• Vehicles without mechanical vacuum pump: Drive chain sprocket mounting pins
• Vehicles with mechanical vacuum pump: Mechanical vacuum pump input shaft
2 High pressure pump drive chain sprocket
• Different versions
3 Valve stem seal
• Replacing => [ Valve Stem Seals ] Service and Repair.
4 Valve spring
• Installed location: Larger diameter faces toward cylinder head
5 Valve spring plate
6 Valve keys
7 Bolt
• 8 Nm
8 Control housing
• Removing and installing => [ Camshafts ] Service and Repair.
• Check control housing strainer for soiling before installation => [ Control Housing Screen, Cleaning ]
• When installing, lightly lubricate compression ring contact surface in control housing
• Disassembling and assembling => [ Disassembling and Assembling Control Housing ]
9 Compression ring
• 3 per camshaft
• Replace if leaking
• When replacing compression rings, do not spread too widely
• Install with gaps offset 120 degrees
• When installing, lightly lubricate compression ring contact surface at camshafts and carefully slide control housing - 8 - over compression ring
10 Nut
• Exhaust camshaft tightening sequence => [ Exhaust Camshaft Tightening
Sequence ]
• Intake camshaft tightening sequence => [ Intake Camshaft Tightening
Sequence ]
11 Bearing cap
• Installed location => [ Camshaft Bearing Cap Installation Location ]
• Installation order => [ Camshaft Bearing Cap Installation Location ]
12 Intake camshaft
• Identification => [ Camshaft Identification ]
• Removing and installing => [ Camshafts ] Service and Repair.
• Measuring axial play => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play.
• Radial clearance, measuring => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play.
• Run out maximum 0.01 mm
13 Exhaust camshaft
• Identification => [ Camshaft Identification ]
• Removing and installing => [ Camshafts ] Service and Repair.
• Measuring axial play => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play.
• Radial clearance, measuring => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play
• Run out maximum 0.01 mm
14 Roller rocker lever
• Do not interchange
• Check roller bearing
• Before installing, check axial play in camshafts => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play.
• Lubricate contact surface
• For assembly, clip with to support element with securing clip - 15 -
15 Securing clip
• Check for secure seat
16 Support element
• With hydraulic valve clearance compensation
• Do not interchange
• Before installing, check axial play in camshafts => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play.
• Lubricate contact surface
17 Cylinder head
• Check valve guides => [ Valve Guides, Checking ] Testing and Inspection.
• Rework valve seats => [ Valve Seats, Reworking Dimensions ] [1][2]Specifications.
18 Intake valve
• Do not rework, only lapping is permitted
• Valve dimensions => [ Valve Dimensions ] Specifications.
• Check valve guides => [ Valve Guides, Checking ] Testing and Inspection.
• Rework valve seats => [ Valve Seats, Reworking Dimensions ] [1][2]Specifications.
19 Exhaust valve
• Do not rework, only lapping is permitted
• Valve dimensions => [ Valve Dimensions ] Specifications.
• Check valve guides => [ Valve Guides, Checking ] Testing and Inspection.
• Rework valve seats => [ Valve Seats, Reworking Dimensions ] [1][2]Specifications.
Camshaft Identification
The camshaft marking is located between cylinder 4 and 5 cam pair.
A Exhaust camshaft; Identification 022 - Index 101
B Intake camshaft; Identification 022 - Index 102
Coat Bearing Caps 7 and 8 Contact Surface with Adhesive Lubricating Paste
- Coat contact surface - shaded - on bearing cap 7 and 8 with adhesive lubricating paste; adhesive lubricating paste.
Camshaft Bearing Cap Installation Location
• Points - arrow A - of intake and exhaust camshaft bearing caps face outwards.
• Identification on bearing caps is legible when read from intake side.
Intake Camshaft - A - Tightening Sequence
- Tighten nuts in 5 stages as follows:
1. Install bearing cap 5 and 9 nuts alternating and diagonally as far as stop.
2. Tighten bearing cap 5 and 9 nuts to 5 Nm + 1/8 additional turn (45°).
3. Tighten bearing cap 1 and 13 nuts to 5 Nm + 1/8 additional turn (45°).
4. Tighten bearing cap 7 nuts to 5 Nm + 1/8 additional turn (45°).
5. Tighten bearing cap 3 and 11 nuts to 5 Nm + 1/8 additional turn (45°).
Exhaust Camshaft - B - Tightening Sequence
- Tighten nuts in 5 stages as follows:
1. Install bearing cap 6 and 10 nuts alternately and diagonally as far as stop.
2. Tighten bearing cap 6 and 10 nuts to 5 Nm + 1/8 additional turn (45°).
3. Tighten bearing cap 2 and 14 nuts to 5 Nm + 1/8 additional turn (45°).
4. Tighten bearing cap 8 nuts to 5 Nm + 1/8 additional turn (45°).
5. Tighten bearing cap 4 and 12 nuts to 5 Nm + 1/8 additional turn (45°).
Disassembling and Assembling Control Housing
1. Guide rail, clipped in at control housing
2. Control housing
3. Camshaft adjustment valve 1 (N205)
4. Camshaft adjustment valve 1 (exhaust) (N318)
5. Bolt
Control Housing Screen, Cleaning
- Unclip screen - 2 - on back side of control housing - 1 - and remove contaminates.