VALVETRAIN Overview

WARNING: This page is about a different variant/trim than selected.

NOTE:

The cylinder head and the cylinder head cover must be replaced together.

Do not start the engine for approximately 30 minutes after installing the camshafts. 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 the gaskets and seals.

Fig 1: Identifying Assembly Overview: Valvetrain

Courtesy of AUDI OF AMERICA, LLC

Exhaust Valve
- Do not reface by grinding, only lapping is permitted
- For the correct valve dimensions, refer to Fig 4
- Valve guides, checking, refer to VALVE GUIDES, CHECKING
Cylinder Head
Valve Guide
- Checking, refer to VALVE GUIDES, CHECKING
Valve Stem Seal
- Replace, refer to VALVE STEM SEALS WITH CYLINDER HEAD INSTALLED , VALVE STEM SEALS WITH CYLINDER HEAD INSTALLED
Valve Spring
Valve Spring Plate
Valve Retainers
hydraulic Adjusting Element
- Do not interchange
- Lubricate contact surface
Exhaust Camshaft
- Removing and installing, refer to CAMSHAFTS
- Check radial clearance using Plastigage (roller rocker lever removed)
- Radial clearance: 0.024 to 0.066 mm
- Run-out: maximum 0.04 mm
Cylinder Head Cover
- With integrated camshaft bearings
- Clean sealing surface, refacing is not permitted.
- Remove old sealant residue.
Bolt
- Replace
- Loosening, refer to Fig 2
- Tightening sequence, refer to Fig 3
O-ring
- Replace
- Coat with engine oil
Plug
Intake Camshaft
- Removing and installing, refer to CAMSHAFTS
- Check radial clearance using Plastigage (roller rocker lever removed)
- Radial clearance: 0.024 to 0.066 mm
- Run-out: maximum 0.04 mm
Cover
- Replace
- Removing with the cylinder head cover installed, pierce through one side of the cover with an awl and pry it out
- Installing CAMSHAFTS .
Intake Valve
- Do not reface by grinding, only lapping is permitted
- For the correct valve dimensions, refer to Fig 4
- Valve guides, checking, refer to VALVE GUIDES, CHECKING

Fig 2: Cylinder Head Cover Loosening Sequence

Courtesy of AUDI OF AMERICA, LLC

-- Loosen the cylinder head cover in a sequence -1 to 6-.

Fig 3: Cylinder Head Cover Tightening Sequence

Courtesy of AUDI OF AMERICA, LLC

-- Replace bolts

-- Hand-tighten bolts in several stages in sequence -1 to 6-.

-- Tighten the bolts in a sequence -1 to 6- to 8 Nm using a torque wrench.

-- Tighten the bolts an additional 90° using a rigid wrench in sequence -1 to 6-.

NOTE:

Ensure guide frame is not tilted.

Fig 4: Identifying Valve Dimensions

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Intake and exhaust valves must not be refaced by grinding. Only lapping is permitted.

Dimension		Intake Valve	Exhaust Valve
Diameter a	mm	33.85 ± 0.10	28.0 ± 0.1
Diameter b	mm	5.98 ± 0.01	5.96 ± 0.01
c	mm	104.0 ± 0.2	101.9 ± 0.2
α	∠°	45	45