Valve mechanism — assembly (Audi A4 B8)

Valve mechanism

Caution! Risk of damage to valves and piston crowns after working on the valve train. Since the hydraulic lifters must be settled, after installing the camshafts, the engine should not be started for about 30 minutes. To ensure this. to ensure that no valves come into contact with the cylinder head during operation, carefully rotate the engine at least 2 revolutions. Cylinder heads with cracks between the valve seats or between the valve seat ring and the spark plug seat threads can be used without reducing service life, provided the cracks are small, no wider than 0.3 mm, or if they affect only the first 4 threads of the spark plug seat threads.

The figure shows the cylinder head of cylinder bank 2 (left).

1. Plug: Install with sealant.
2. Cylinder head.
3. Oil seal.
4. Valve spring.
5. Hydraulic compensator: mark installation. paint position for reinstallation: lubricate the working surfaces before installation.
6. Valve spring plate.
7. Valve checks.
8. Roller lever: different designs for the inlet and outlet side, do not confuse; check the roller bearing for ease of movement; lubricate the working surfaces before installation; secure with safety clip "pos. 9" on hydraulic compensator "pos. 5".
9. Safety bracket: different designs for the inlet and outlet side, do not confuse; check the reliability of the fastening.
10. Intake camshaft: with 3 sliders; do not disassemble; maximum runout: 0.04 mm.
11. Bolt: replace.
12. Executive element of the phase shifter.
13. Bolt: 5 Nm.
14. Sealing ring: replace.
15. Camshaft frame: with integrated camshaft bearings.
16/17. Rectangular section ring.
18. Exhaust camshaft: maximum runout: 0.04 mm.
19. Mesh oil filter.
20. Inlet valve: cannot be machined, only lapping is allowed; mark mont. reinstallation position.
21. Exhaust valve: cannot be machined, only lapping is allowed; mark mont. reinstallation position.

Camshaft frame - last and tightening torque

The illustration shows the left cylinder head camshaft frame. Replace the camshaft frame bolts. Tighten bolts "1...21" in 3 steps.

1. Screw in manually until it stops. The camshaft frame must lie on the cylinder head over its entire surface area. 2. Tighten to 8 Nm. 3. Tighten further by 90°.