Valvetrain Component Overview
Valvetrain Component 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 Camshaft Adjuster, Exhaust Side
• Identification: "32A"
• Removal and installation, refer to => [ Camshaft Timing Chain ] Camshaft Timing Chain
2 Bolt
• For removal and installation, counter-hold at camshaft hex head with open-end spanner, refer to => [ Camshaft Timing Chain ] Camshaft Timing Chain
• Replace
• Tightening specifications - 23 - => [ Bolt ] Timing Chain Component Overview
3 Camshaft Adjuster, Intake Side
• Identification: "24E"
• Removal and installation, refer to => [ Camshaft Timing Chain ] Camshaft Timing Chain
4 Control Housing
• Removal and installation, refer to => [ Camshafts ] Service and Repair
• Check control housing strainer for contamination before installation, refer to => [ Control Housing Screen, Cleaning ].
• Lightly lubricate contact surfaces of oil seals before installing
• Disassembling and assembling, refer to => [ Disassembling and Assembling Control Housing ]
5 Valve Stem Seal
• Replacing, refer to => [ Valve Stem Seals with Cylinder Head Installed, Replacing ] Valve Stem Seals with Cylinder Head Installed, Replacing.
6 Valve Spring
• Installation position: Larger diameter down
7 Valve Spring Plate
8 Valve Keys
9 Compression Ring
• 3 per camshaft
• Replace if leaking
• When replacing compression rings, do not spread too widely
• Install with gaps offset 120°
• When installing control housing - 4 -, lightly lubricate compression ring contact surface
10 Nut
• Tightening specifications and tightening sequence, refer to => [ Camshafts - Tightening Specifications and Tightening
Sequence ]
11 Bearing Cap
• Installed location, refer to => [ Camshaft Bearing Cap Installation Location ]
• Installation order, refer to => [ Camshaft Bearing Cap Installation Location ]
12 Intake Camshaft
• Identification, refer to => [ Camshaft Identification ]
• Removal and installation, refer to => [ Camshafts ] Service and Repair
• Measuring axial play, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play
• Run-out maximum 0.01 mm
13 Exhaust Camshaft
• Identification, refer to => [ Camshaft Identification ]
• Removal and installation, refer to => [ Camshafts ] Service and Repair
• Measuring axial play, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Radial clearance, measuring, refer to => [ 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, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Lubricate contact surface
• For assembly, clip to the hydraulic adjusting element with securing clip - 15 -
15 Securing Clip
• Check for secure seat
16 Hydraulic Adjusting Elements
• Do not interchange
• Before installing, check axial play in camshafts, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Lubricate contact surface
17 Cylinder Head
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
• Reface valve seats, refer to => [ Valve Seats, Refacing ] [1][2]Specifications
18 Intake Valve
• Do not rework, only lapping is permitted
• Valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
• Rework valve seats, refer to => [ Valve Seats, Refacing ] [1][2]Specifications
19 Exhaust Valve
• Do not rework, only lapping is permitted
• Valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
• Rework valve seats, refer to => [ Valve Seats, Refacing ] [1][2]Specifications
20 Bolt
• 8 Nm
Camshaft Identification
The camshaft marking is located between the 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
- Lightly coat contact surface - shaded - on bearing cap 7 and 8 with adhesive lubricating paste; adhesive lubricating paste.
Camshaft Bearing Cap Installation Location
• Tops of intake and exhaust camshaft bearing caps - arrow A - face toward outside.
Camshafts - Tightening Specifications and Tightening Sequence
- Tighten nuts on intake camshaft - A - in 5 stages as follows:
1. Install bearing cap 5 and 9 nuts alternately and diagonally as far as stop.
2. Tighten the bearing cap nuts 5 and 9 to 5 Nm plus an additional 45° (1/8 turn).
3. Tighten the bearing cap nuts 1 and 13 to 5 Nm plus an additional 45° (1/8 turn).
4. Tighten the bearing cap nuts 7 to 5 Nm plus an additional 45° (1/8 turn).
5. Tighten the bearing cap nuts 3 and 11 to 5 Nm plus an additional 45° (1/8 turn).
- Tighten nuts on exhaust camshaft - B - in 5 stages as follows:
1. Install bearing cap 6 and 10 nuts alternately and diagonally as far as stop.
2. Tighten the bearing cap nuts 6 and 10 to 5 Nm plus an additional 45° (1/8 turn).
3. Tighten the bearing cap nuts 2 and 14 to 5 Nm plus an additional 45° (1/8 turn).
4. Tighten the bearing cap nuts 8 to 5 Nm plus an additional 45° (1/8 turn).
5. Tighten the bearing cap nuts 4 and 12 to 5 Nm plus an additional 45° (1/8 turn).
Disassembling and Assembling Control Housing
1. Guide track, 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 dirt.