Valvetrain Assembly Overview

Valvetrain Assembly Overview

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 width of max. 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
^ Cylinder head and guide frame may only be replaced together.
^ 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.
^ Always replace gaskets and seals.





1. 50 Nm + 180 degree (1/2 turn) additional turn
^ Replace + Use counter-holder 3036 to loosen and tighten
2. Camshaft sprocket
^ Use counter-holder 3036 to loosen and tighten
3. Seal
4. Cylinder head
5. Valve guide
6. Valve stem seal
7. Valve spring
8. Top valve spring retainer
9. Valve keepers
10. Hydraulic valve play balancing element
^ Do not interchange
^ Lubricate contact surface
11. Fitted key
^ Check for secure seat
12. Exhaust camshaft
^ Check radial clearance using Plastigage (roller cam follower removed) wear limit: 0.1 mm
^ Run-out: max. 0,035 mm
13. Guide frame
^ With integrated camshaft bearings
^ Clean sealing surface, reworking is not permitted.
^ Remove old sealant residue.
14. 8 Nm + 1/4 turn (90 degree)
^ Replace
15. Camshaft adjuster
16. 20 Nm + 1/8 turn (45 degree)
^ Use counter-holder 3036 to loosen and tighten
17. Intake camshaft
^ Checking radial clearance with Plastigage, Wear limit: 0.1 mm
^ Run-out: max. 0.035 mm
18. Chain tensioner
^ Before removing, secure with locking pin T10115
19. Drive chain
^ Check for wear
20. 10 Nm
21. 10 Nm
22. Camshaft Position (CMP) sensor G40
23. Exhaust valve
^ Do not rework, only grinding is permitted
24. Intake valve
^ Do not rework, only grinding is permitted
25. Cap
^ Replace
^ Removing: Insert a screwdriver into center of cap and pry out.
^ Installing: Do not use sealant, press in 1 to 2 mm using pressure piece 3334.