Overview - Valve Train

Fig 1: Valve Train Overview

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Bolt
- 100 Nm
- Use Counterhold - Crankshaft Sprocket 3415 when loosening or tightening
Camshaft Sprocket
Sealing Ring
- Replacing, refer to CAMSHAFT SEAL, REMOVING AND INSTALLING .
Woodruff Key
- Make sure it is secure
Bolt
- 20 Nm
Bearing Cap
- Installed position, refer to Fig 4
- Installation order, refer to CAMSHAFT, REMOVING AND INSTALLING
- Lightly coat the contact surface of bearing cap 1 with SealantAMV 174 004 01.
Camshaft
- Axial Play, Checking, refer to Fig 3.
- Removing and installing, refer to CAMSHAFT, REMOVING AND INSTALLING .
- Check radial clearance with Plastigage^®
  Wear limit: 0.1 mm Run-out: max. 0.05 mm
Hydraulic Valve Lifter
- Do not interchange
- With hydraulic valve clearance compensation
- Checking, refer to HYDRAULIC VALVE LIFTER, CHECKING .
- Place on running surface when setting down
- Before installing, check axial play of camshafts, refer to Fig 3
- Lubricate contact surface
Valve Retainers
Upper Valve Spring Retainer
Valve Spring
- Removing and installing:
  - Cylinder head removed using Valve Spring Compressor2037
  - Cylinder head installed, refer to VALVE STEM SEALS, REMOVING AND INSTALLING .
Valve Stem Seal
- Replacing, refer to VALVE STEM SEALS, REMOVING AND INSTALLING .
Valve Guide
- Checking, refer to VALVE GUIDES, CHECKING .
- Replacing, refer to VALVE GUIDES, REPLACING .
- Repair guide with shoulder
Cylinder Head
- Resurfacing sealing surfaces, refer to Fig 2
- Valve seats, reworking, refer to VALVE SEATS, REWORKING .
Valves
- Do not rework, only lapping is permitted
- Valve dimensions, refer to Fig 5
Rear Toothed Belt Guard
Bolt
- 20 Nm
Camshaft Position Sensor -G40-

Fig 2: Cylinder Head Reworking Limit

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Reworking dimension, cylinder head:

-a- = minimum 132.6 mm

NOTE:

If the sealing surface is reworked, then place the valves deeper; rework the valve sealing rings. Otherwise the valve will hit up against the pistons. Be careful not to exceed the minimum dimension, refer to VALVE SEATS, REWORKING .

Fig 3: Camshaft Axial Clearance, Checking

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Special tools and workshop equipment required

Dial Gauge Holder VW387
Dial Gauge

Test Sequence

-- Measure with valve lifters removed and with first and last bearing cap installed.

Wear limit: 0.15 mm

Fig 4: Identifying Correct & Incorrect Bearing Cap Position

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Observe central alignment.

-- Before installing camshaft, set bearing caps in place and determine installation position.

Fig 5: Identifying Valve Dimensions

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

NOTE:

Valves must not be reworked. Only lapping is permitted.

Dimension		Intake Valve	Exhaust Valve
Diameter a	mm	39.50 ± 0.15	32.90 ± 0.15
Diameter b	mm	6.92 ± 0.02	6.92 ± 0.02
c	mm	91.85	91.15
α	∠°	45	45