Valvetrain Overview
Valvetrain Overview
• Secure the engine to the engine and transmission holder (VAS 6095) when working on it.
• Cylinder heads with cracks between the valve seats can continue to be used without reducing service life, as long as the cracks have a Max. width of 0.5 mm.
1 Bolt
• 20 Nm + 90° (1/4) additional turn.
• Always replace
• Observe the sequence for loosening and tightening, refer to => [ Camshaft ] Service and Repair.
2 Rocker Lever Shaft with Lever
• Do not interchange.
3 Bearing Cap
• To install, seal the joint surfaces of the outer bearing cap with sealant (AMV 176 501). Refer to => [ Seal Joint Surfaces for the Outer Bearing
Caps ].
4 Valve Lifter
• Do not interchange.
• With hydraulic valve clearance compensation.
• Place on running surface when setting down.
• Before installing, check the camshaft axial play. Refer to => [ Camshaft, Checking Axial Play ].
• Lubricate the contact surface.
• Before removing, remove the camshaft bearing caps.
5 Valve Retainers
6 Valve Spring Plate
7 Outer Valve Spring
• Removing and installing, refer to => [ Valve Stem Seals ] Service and Repair.
8 Inner Valve Spring
• Removing and installing, refer to => [ Valve Stem Seals ] Service and Repair.
9 Valve Stem Seal
• Removing and installing, refer to => [ Valve Stem Seals ] Service and Repair.
10 Diamond Disc
• Always replace
11 Sleeve
• For linkage mounting components.
12 Cylinder Head
• Observe the "Notes".
• Reface the valve seats. Refer to => [ Valve Seat, Refacing ] Service and Repair.
13 Valves
• Valve dimensions, refer to => [ Valve Dimensions ].
14 Pump Injector Unit
• Removing and installing, refer to => [ Pump Injector Unit ] Pump Injector Unit.
15 Washer
• For the cylinder head bolts.
• Insert into the cylinder head before assembling the bearing caps.
• Observe the "Precautions". Refer to => [ All cylinder head bolts, except numbers in tightening sequence must be installed with notched washers ] Cylinder Heads.
16 Bearing Shell
• Do not interchange used bearing shells (mark them).
• Make sure the retaining tabs are engaged properly in the bearing caps and cylinder head.
17 Camshaft
• Checking axial play, refer to => [ Camshaft, Checking Axial Play ].
• Identification, valve timing. Refer to => [ Camshaft Identification, Valve Timing ].
• Removing and installing, refer to => [ Camshaft ] Service and Repair.
• Check radial clearance using Plastigage, Wear limit: 0.11 mm.
• Runout: Max. 0.01 mm.
18 Bearing Shell
• Do not interchange used bearing shells (mark them).
• Make sure the retaining tabs are engaged properly in the bearing caps and cylinder head.
19 Bolt
• Always replace
• Observe the sequence for loosening and tightening. Refer to => [ Cylinder Heads ] Cylinder Heads.
• Before installing, install washers => [ (Item 15) Washer ] into the cylinder head.
20 Bolt
• 8 Nm + 90° (1/4) additional turn.
• Always replace
Camshaft, Checking Axial Play
Special tools, testers and auxiliary items required
• Dial Gauge Holder (VW 387)
• Dial Gauge
Test Sequence:
Measurement with valve lifters removed and bearing caps installed:
Cylinder bank 1:
• Bearing caps 2, 4 and 6 installed
Cylinder bank 2:
• Bearing caps 9, 11 and 13 installed
Wear limit: Max. 0.15 mm
Seal Joint Surfaces for the Outer Bearing Caps
Special tools, testers and auxiliary items required
• Sealant (AMV 176 501)
Procedure:
- Apply the sealant (AMV 176 501) thinly and evenly on the surface - 1 -.
Cylinder bank 1:
• Seal bearing caps 1 and 7 with sealant (AMV 176 501)
Cylinder bank 2:
• Seal bearing caps 8 and 14 with sealant (AMV 176 501)
Valve Dimensions
• Valves must not be reworked. Only lapping is permitted.
Camshaft Identification, Valve Timing
Identification
• Base circle of valve cams: a = diameter 52.8 mm
• Identification by numbers and letters stamped on face surface of camshaft drive side.
Valve Timing at 1 mm Valve Lift
