Valvetrain Component Overview
Valvetrain Component Overview
• After installing the camshafts, the engine may not be started for approximately 30 minutes. The hydraulic adjusting elements must seat themselves (otherwise the valves will seat themselves on the pistons).
• After working on the valvetrain and lifters, carefully rotate the crankshaft by hand at least 2 full revolutions before starting to be sure that valves do not strike the pistons.
1 Camshaft Adjuster, Exhaust Side
• Identification: "32A"
• Removal and installation, refer to => [ Camshaft Timing Chain ] Camshaft Timing Chain
2 Bolt
• Replace
• Counter-hold camshaft using fork wrench SW 32 for removal and installation => [ Camshaft Timing Chain ] Camshaft Timing Chain
• Tightening specifications item - 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 soiling before installation.
• Lightly lubricate contact surfaces of oil seals before installing
5 Valve Stem Seal
• Replacing with the cylinder head installed, refer to => [ Valve Stem Seals with Cylinder Head Installed, Replacing ] Valve Stem Seals With Cylinder Head Installed, Replacing
• Replacing with the cylinder head removed, refer to => [ Valve Stem Seals with Cylinder Head Removed ] Valve Stem Seals With Cylinder Head Removed
6 Valve Spring
• Installation position: Larger dia. down
7 Valve Spring Plate
8 Valve Keys
9 Piston Rings
• 3 per camshaft
• Replace if leaking
• When replacing piston rings, do not spread too widely
• Install with gaps offset 120°
• When installing control housing item - 4 -lightly lubricate contact surfaces of piston rings
10 Nut
11 Bearing Cap
• Installation order => [ Installing ] Service and Repair
12 Intake Camshaft
• Check radial clearance with Plastigage
• Radial clearance wear limit: 0.1 mm
• Run-out: max. 0.01 mm
• Checking axial play, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Removal and installation, refer to => [ Camshafts ] Service and Repair
13 Exhaust Camshaft
• Check radial clearance with Plastigage
• Radial clearance wear limit: 0.1 mm
• Run-out: max. 0.01 mm
• Checking axial play, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Removal and installation, refer to => [ Camshafts ] Service and Repair
14 Roller Rocker Lever
• Do not interchange
• Check roller bearing
• Before installing, check axial play in camshafts, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Lubricate contact surface
• Using the locking clamp, clip - item 15 - onto the hydraulic adjusting element
15 Securing Clip
• Check for secure seat
16 Hydraulic Adjusting Element
• Do not interchange
• Before installing, check axial play in camshafts, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Lubricate contact surface
17 Cylinder Head
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
• Reface valve seat, refer to => [ Refacing Valve Seats ] Service and Repair
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
• Refacing valve seats, refer to => [ Refacing Valve Seats ] Service and Repair
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
• Reface valve seats, refer to => [ Refacing Valve Seats ] Service and Repair
20 Bolt
• 8 Nm
Camshaft Identification
Camshaft identification is located between cylinder 4 and cylinder 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 bearing cap 7 and 8 contact surface - hatched area - with 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
Checking Strainer of Control Housing for Contamination
- Unclip screen - 2 - at backside of control housing - 1 - and remove any contaminants.