Valvetrain Assembly Overview
Valvetrain Assembly Overview
• When using an exchanged cylinder head with camshaft installed, the contact surfaces between the lifters and cam lobes must be lubricated before installing the cylinder head cover.
• The plastic protectors installed to protect the open valves must only be removed immediately before fitting the cylinder head.
• When cylinder head is replaced, all coolant must also be replaced.
• Cylinder heads with cracks between the valve seats can continue to be used without reducing service life, as long as the tears have a width of max. 0.5 mm.
• Do not mill the valve seats in the cylinder head; only grinding of the valves is permissible.
• After installing the camshafts, the engine may not be started for approximately 30 minutes. The hydraulic equalization elements 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 gaskets and seals.
1 20 Nm + 90° (1/4 turn) additional turn
• Replace
• Follow sequence for loosening and tightening => [ Camshaft ] Service and Repair.
2 Rocker arm axle
• Do not interchange
3 Cylinder head bolt
• Replace
• Follow sequence for loosening and tightening => [ Cylinder Head ] Cylinder Head.
• Before installing, insert shims => [ (Item 4) Washer ] into cylinder head
4 Washer
• For cylinder head bolts
• Insert into cylinder head before assembling bearing caps
5 Valve lifter
• Do not interchange
• with hydraulic valve clearance compensation
• place on running surface when setting down
• Before installing, check axial play of camshafts => [ Camshaft, Checking Axial Play ] Testing and Inspection
• Lubricate contact surface
• Before removing, remove bearing caps for camshaft
6 Valve keepers
7 Valve spring plate
8 Outer valve spring
• Removing and installing, cylinder head removed: With valve spring compressor (2037)
• Removing and installing, cylinder head installed: => [ Valve Stem Seals ] Service and Repair.
9 Inner valve spring
• Removing and installing, cylinder head removed: With valve spring compressor (2037)
• Removing and installing, cylinder head installed: => [ Valve Stem Seals ] Service and Repair.
10 Valve stem seal
• Replacing => [ Valve Stem Seals ] Service and Repair.
11 Valve guide
• Checking => [ Valve Guides, Checking ] Testing and Inspection.
12 Pump-injector unit
• Removing and installing => [ Pump Injector Unit ] Pump Injector Unit.
13 Cylinder head
• See note.
14 Seal
• Do not additionally oil or grease sealing lip of oil seal
• Before installing, remove oil remains from camshaft journal with a clean cloth.
• To install, tape over the groove on the taper of the camshaft with commercially available adhesive strip (e.g. scotch tape)
• Removing and installing => [ Camshaft Seal ] Service and Repair.
15 Valves
• Valve dimensions => [ Valve Dimensions ] [1][2]Specifications
16 Bearing shell
• Do not interchange used bearing shells (mark)
• Make sure retaining tabs are engaged properly in bearing caps and cylinder head
17 Camshaft
• Checking axial play => [ Camshaft, Checking Axial Play ] Testing and Inspection
• Removing and installing => [ Camshaft ] Service and Repair.
• Checking radial clearance with Plastigage, Wear limit: 0.11 mm
• Run out: max. 0.04 mm
18 Bearing cap
• Installation order => [ Camshaft ] Service and Repair.
• When installing, seal the separating surfaces of bearing caps 1 through 5 with sealant, black (AMV 174 004 01) => [ Bearing Caps 1 and 5, Sealing Separating Surfaces ] Bearing Caps 1 and 5, Sealing Separating Surfaces
19 8 Nm + 90° (1/4 turn) additional turn
• Replace