SEAT Workshop Service and Repair Manuals

Repairing valve gear

t

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.

t	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.

1 -

10 Nm

2 -	Inlet camshaft

q	Checking axial clearance → Fig..

q	Removing and installing → Chapter.

q	Check radial clearance with plastigage, wear limit: 0.1 mm.

q	Runout: max. 0.01 mm.

3 -	Drive chain

q	Before removing, mark direction of rotation (installation position) → Chapter, Removing and installing camshafts.

4 -

10 Nm

5 -	Chain tensioner

q	Must seat on dowel sleeves.

q	Only rotate engine when chain tensioner is installed.

q	Secure with chain tensioner retainer -3366- before removing → Chapter, Removing and installing camshafts.

q	Seal transitions between chain tensioner/cylinder head → Fig.

6 -	Rubber/metal gasket

q	Replacement → Chapter, Removing and installing camshafts.

7 -	Cylinder head

q	Removing and installing → Chapter.

q	Reworking valve seats → Chapter.

q	Reworking sealing surface → Fig..

q	Sealing transition points → Fig. and → Fig..

8 -

Valves

q	Do not rework, only lapping-in is permitted.

q	Valve dimensions → Fig..

q	Exhaust valves with sodium filling: Observe disposal instructions → Fig..

9 -

Seal

q	Renewing → Chapter.

10 -

Trim

q	For Hall sender.

q	When installing note fixing arrangement.

11 -

Washer

q

Conical.

12 -

25 Nm

13 -	Hall sender -G40- housing

q	Check Hall sender -G40- → Rep. Gr.28.

14 -

10 Nm

15 -

65 Nm

q	Use counterhold tool -3036- to loosen and tighten

16 -	Camshaft pulley

q	Note installation position: the narrow web of camshaft pulley faces outwards and the TDC No. 1 cylinder marking is visible.

q	Note position when installing toothed belt → Chapter, removing, installing and tensioning toothed belt.

17 -

Seal

q	Renewing → Chapter.

18 -	Valve guide

q	Checking → Chapter.

19 -	Valve stem oil seal

q	Renewing → Chapter.

20 -	Valve spring

q	Removing and installing:

Cylinder head removed: With valve spring tool -3362- and press piece -3362/1-.

Cylinder head installed: → Chapter, Renewing valve stem oil seals

21 -	Valve spring plate

22 -

Cotters

23 -	Bucket tappet

q	Do not interchange.

q	With hydraulic valve clearance compensation.

q	Checking → Chapter.

q	Store with cam contact surface downwards

q	Before installing, check camshaft axial clearance → Fig..

q	Oil contact surface.

24 -	Inlet camshaft bearing cap

q	Observe installation position and installation sequence → Chapter, Removing and installing camshaft.

25 -	Double bearing cap

q	Must seat on dowel sleeves.

q	Lightly coat contact surface with sealing compound -AMV 174 004 01-, observe installation position and installation sequence → Chapter, Removing and installing camshaft.

q	Seal transition points between double bearing cap and cylinder head → Fig..

26 -	Exhaust camshaft bearing cap

q	Observe installation position and installation sequence → Chapter, Removing and installing camshaft.

27 -	Exhaust camshaft

q	Checking axial clearance → Fig..

q	Removing and installing → Chapter.

q	Check radial clearance with plastigage, wear limit: 0.1 mm.

q	Runout: max. 0.01 mm.

Reworking cylinder head sealing surface The dimension for reworking is measured through the holes for the cylinder head bolts. a = minimum 139.2 mm.

Checking camshaft axial clearance Special tools and workshop equipment required t  Universal dial gauge bracket -VW 387- t  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
Ø a	mm	26.9	29.9
Ø b	mm	5.963	5.943
c	mm	104.84...105.34	103.64...104.14
α	∠°	45	45

Note! Worn sodium filled exhaust valves must not be disposed of without first preparing the valves. They must be cut through in the centre of the stem with a hacksaw. They must not come into contact with water. The valves prepared in this way can then be thrown into a bucket of water, a maximum of ten at a time. When doing this step back quickly because a sudden chemical reaction causes the sodium filling to burn. After this treatment, the valves can be disposed of as normal scrap.

Sealing transition points between double bearing cap and cylinder head Special tools and workshop equipment required t  Sealing compound -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 t  Sealing compound -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.