Repairing valve gear — VW

VW
Sharan
1996
Power unit
4-cylinder injection engine (5-valve), mechanics
Edition
03.2011
Repairing valve gear
Note
Cylinder heads which have cracks between the valve seats or between a valve seat insert and the spark plug thread can be used further without reducing service life, provided the cracks do not exceed a maximum of 0.3 mm in width, or when no more than the first 4 turns of the spark plug thread are cracked.
When new bucket tappets have been installed the engine must not be started for about 30 minutes. (Otherwise valves will contact pistons.) Then turn crankshaft two full revolutions.
10 Nm
Inlet camshaft
Checking axial clearance
Fig.
.
Removing and installing
Chapter
.
Check radial clearance with Plastigage, wear limit: 0.1 mm
Runout: max. 0.01 mm.
Drive chain
Before removing, mark direction of rotation (installation position)
Chapter
, Removing and installing camshafts.
10 Nm
Chain tensioner
Must seat on dowel sleeves.
Only rotate engine when chain tensioner is installed.
Before removing, secure with
chain tensioner retainer
3366
Chapter
, Removing and installing camshafts.
Seal transitions between chain tensioner/cylinder head
Fig.
Bonded rubber seal
Renewing
Chapter
, Removing and installing camshafts
Cylinder head
Removing and installing
Chapter
.
Reworking valve seat
Chapter
.
Reworking sealing surface
Fig.
.
Sealing transitions
Fig.
and
Fig.
Valves
Do not rework, only lapping-in is permitted.
Valve dimensions
Fig.
.
Exhaust valves with sodium filling: Observe disposal instructions
Fig.
.
Seal
Renewing
Chapter
.
Screen
For Hall sender.
When installing note fixing arrangement.
Washer
Conical.
25 Nm
Housing for
Hall sender
G40
Check
Hall sender
G40
Rep. gr.
28
Checking Hall sender
.
10 Nm
65 Nm
Use
counterhold tool
3036
to loosen and tighten.
Camshaft pulley
Note installation position: the narrow web of camshaft toothed belt pulley faces outwards and the TDC No. 1 cylinder marking is visible.
Note position when installing toothed belt
Chapter
, removing, installing and tensioning toothed belt.
Seal
Renewing
Chapter
.
Valve guide
Check
Chapter
.
Valve stem seal
Renewing
Chapter
.
Valve spring
Removing and installing:
Cylinder head removed: use
valve spring tool
3362
and
thrust piece
3362/1
Cylinder head installed:
Chapter
, Renewing valve stem oil seals
Valve spring plate
Cotters
Bucket tappet
Do not interchange.
With hydraulic valve clearance compensation.
Check
Chapter
.
Set down with contact surface facing downwards.
Before installing, check camshaft axial clearance
Fig.
.
Oil contact surface.
Inlet camshaft bearing cap
Observe installation position and installation sequence
Chapter
, Removing and installing camshafts
Double bearing cap
Must seat on dowel sleeves.
Lightly coat contact surface with
sealant
AMV 174 004 01
and observe installation position and installation sequence
Chapter
, Removing and installing camshafts
Seal transition points between double bearing cap and cylinder head
Fig.
.
Exhaust camshaft bearing cap
Observe installation position and installation sequence
Chapter
, Removing and installing camshafts
Exhaust camshaft
Checking axial clearance
Fig.
.
Removing and installing
Chapter
.
Check radial clearance with Plastigage, wear limit: 0.1 mm
Runout: max. 0.01 mm.
Reworking cylinder head sealing surface
The reworking dimension is measured through the holes for the cylinder head bolts a = at least 139.2 mm
Checking camshaft axial clearance
Special tools and workshop equipment required
Universal dial gauge bracket
VW 387
Dial gauge
Test procedure
Check with bucket tappets and chain removed and No. 2 and 4 bearing caps fitted.
Wear limit: max. 0.2 mm
Valve dimensions
Note
Valves must not be reworked. Only lapping-in is permitted.
Dimension
Inlet valve
Exhaust valve
∅ a
mm
26.9
29.9
∅ b
mm
5.963
5.943
c
mm
104.84...105.34
103.64...104.14
α
∠°
45
45
Note
Care must be taken when disposing of old sodium-cooled exhaust valves. They must be cut through in the centre of the stem with a hacksaw. When doing this they 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. After this treatment, the valves can be scrapped as normal scrap.
Sealing transition points between double bearing cap and cylinder head
Special tools and workshop equipment required
Sealant
D 454 300 A2
Carefully apply a thin coat of
sealing compound
D 454 300 A2
to both edges of sealing surfaces between double bearing cap and cylinder head
arrows
using a small screwdriver.
Seal transitions between chain tensioner/cylinder head
Special tools and workshop equipment required
Sealant
D 454 300 A2
Carefully apply a thin coat of
sealing compound
D 454 300 A2
to both edges of sealing surfaces between chain tensioner/cylinder head
arrows
using a small screwdriver.