VALVETRAIN Overview
WARNING: This page is about a different variant/trim than selected.
NOTE:
Cylinder heads with cracks between the valve seats, or between the valve seat and the spark plug threads, can continue to be used without reducing the service life, as long as the cracks have a Max. width of 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
The cylinder head and guide frame must be replaced together.
Do not start the engine for approximately 30 minutes after installing the camshafts. The hydraulic lash adjusters must seat themselves (otherwise the valves will crash into 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.
Always replace the gaskets and seals.
- Bolt
- 50 Nm + 180° (1/2) additional turn.
- Always replace
- Use the retainer -3036- to loosen and tighten.
- Camshaft Sprocket
- Use the retainer -3036- to loosen and tighten.
- Seal
- Removing and installing, refer to EXHAUST CAMSHAFT SEAL .
- Cylinder Head
- Valve Guide
- Checking, refer to VALVE GUIDE, CHECKING .
- Valve Stem Seal
- Removing and installing, refer to VALVE STEM SEALS .
- Valve Spring
- Spring Seat
- Valve Retainer
- Hydraulic Lash Adjuster
- Do not interchange.
- Lubricate the contact surface.
- Woodruff Key
- Make sure it is secure.
- Exhaust Camshaft
- Check the radial clearance using Plastigage (roller rocker arm removed) wear limit: 0.1 mm.
- Runout: Max. 0.035 mm.
- Guide Frame
- With integrated camshaft bearings.
- Clean the sealing surface, reworking is not permitted.
- Remove the old sealant residue.
- Bolt
- 8 Nm + 90° (1/4) additional turn.
- Always replace.
- Camshaft Adjuster
- Removing and installing, refer to CAMSHAFT ADJUSTER .
- Bolt
- 20 Nm + 45° (1/8) additional turn.
- Always replace.
- Use the camshaft clamp -T10252- to loosen and tighten.
- Intake Camshaft
- Check the radial clearance with Plastigage, Wear limit: 0.1 mm.
- Runout: Max. 0.035 mm.
- Chain Tensioner
- Before removing, secure using the locking pin -T10115-.
- Drive Chain
- Removing and installing, refer to CAMSHAFT ADJUSTER .
- Check for wear
- Bolt
- 10 Nm
- Bolt
- 10 Nm
- Camshaft Position Sensor -G40-
- Exhaust Valve
- Do not rework, only lapping is permitted.
- For the correct valve dimensions, refer to VALVE DIMENSIONS .
- Valve guide, checking. Refer to VALVE GUIDE, CHECKING .
- Intake Valve
- Do not rework, only lapping is permitted.
- For the correct valve dimensions, refer to VALVE DIMENSIONS .
- Valve guide, checking. Refer to VALVE GUIDE, CHECKING .
- Cap
- Always replace.
- Removing: Insert a screwdriver into the center and pry out.
- Installing: Do not use sealant, press in 1 to 2 mm using the thrust piece -3334-.