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Checking axial clearance of camshafts > < Servicing valve gear

A4 Mk2

Valve gear - exploded view
Valve gear - exploded view
  Note
The following diagram shows the cylinder head (right-side).
   
1 - Double bearing cap
q   Before installing, coat contact surfaces of front and rear bearing caps lightly with sealant → Fig.; Sealant → Parts catalogue
2 - 10 Nm
3 - Bearing cap on exhaust camshaft
q   Watch position of dowel sleeve
q   Note installation position and allocation → Anchor
4 - Exhaust camshaft
q   Checking axial clearance → Chapter
q   Removing and installing → Chapter
q   Check radial clearance with Plastigage (bucket tappets removed)
q   Radial clearance: wear limit: 0.1 mm
q   Runout: max. 0.01 mm
5 - Cap
q   Renewing → Chapter
6 - Bearing cap on inlet camshaft
q   Watch position of dowel sleeve
q   Note installation position and allocation → Anchor
7 - Inlet camshaft
q   Checking axial clearance → Chapter
q   Removing and installing → Chapter
q   Check radial clearance with Plastigage (bucket tappets removed)
q   Radial clearance: wear limit: 0.1 mm
q   Runout: max. 0.01 mm
8 - Drive chain
q   Installing → Anchor
9 - 10 Nm
10 - Mechanical camshaft adjuster
q   With inlet camshaft control valve 1 -N205-
q   Before removing, lock in position with chain tensioner retainer -3366- → Chapter
11 - Hydraulic bucket tappet (inlet valve)
q   Checking → Chapter
q   Removing and installing → Chapter
q   Do not interchange (mark allocation)
q   Place down with contact surface facing downwards
q   Check axial clearance of camshaft before installing → Chapter
q   Lubricate contact surface
12 - Valve cotters
13 - Valve spring plate
14 - Valve spring
15 - Valve stem oil seal
q   Renewing → Chapter
16 - Rubber/metal gasket
q   Renew
17 - Seal
q   Renew
18 - Cylinder head
q   See note → Chapter
q   Checking valve guides, grinding-in valve seats → Chapter
q   Machining valve seats → Chapter
19 - Exhaust valve
q   Do not machine, only grinding-in is permitted
q   Valve dimensions → Fig.
q   Checking valve guides, grinding-in valve seats → Chapter
20 - Inlet valve
q   Do not machine, only grinding-in is permitted
q   Valve dimensions → Fig.
q   Checking valve guides, grinding-in valve seats → Chapter
21 - Oil seal
q   Note direction of rotation
q   Renewing → Chapter and → Chapter
22 - Rotor for Hall sender
q   Note fitting position (notch on camshaft)
23 - Washer
q   Conical
24 - 25 Nm
25 - Hall sender
26 - 10 Nm
27 - 55 Nm
28 - Camshaft sprocket
29 - Oil seal
q   Note direction of rotation
q   Renewing → Chapter
30 - Hydraulic bucket tappet (exhaust valve)
q   Checking → Chapter
q   Removing and installing → Chapter
q   Do not interchange (mark allocation)
q   Place down with contact surface facing downwards
q   Check axial clearance of camshaft before installing → Chapter
q   Lubricate contact surface

   
Valve dimensions
  Note
Valves are not to be machined. Only grinding-in is permitted.
  A15-0326
DimensionInlet valveExhaust valve
Ø amm26.80 … 7.0029.80 … 30.00
Ø bmm5.96 … 5.975.94 … 5.95
cmm104.84 … 105.34103.64 … 104.14
α∠°4545

  WARNING
t  Care must be taken when disposing of old sodium-cooled exhaust valves.
t  The valves must be sawn in two with a metal saw between the centre of the stem and valve head. When doing so, the valves must not come into contact with water. After preparing the valves, throw a maximum of ten into a bucket of water. Then step away immediately, since a chemical reaction will occur in which the sodium filling burns.
t  After performing these steps the valves can be disposed of in the normal way.
   
Applying sealant to bearing cap
–  Apply a small quantity of sealant to the hatched area of the double bearing cap and the outer bearing cap adjacent to the camshaft adjuster and fit the bearing cap (pay attention to dowel sleeves); Sealant → Parts catalogue.
  A15-0084

Checking axial clearance of camshafts > < Servicing valve gear