SEAT Workshop Service and Repair Manuals

Servicing valve gear

t	Cylinder heads which have cracks between the valve seats or between valve seat inserts 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 four spark plug threads are cracked.

t	After installing new bucket tappets the engine must not be started for approx. 30 minutes (otherwise valves will strike pistons), then turn crankshaft two rotations.

1 -

65 Nm

q	Use counter-hold -T20018A- to loosen and tighten

2 -	Camshaft sprocket

q	Note installation position: The small web of the camshaft sprocket points outwards and the No. 1 Cyl. TDC marking is visible

3 -

Oil seal

q	Lightly oil sealing lip of oil seal

q	Renewing → Chapter

4 -	Cylinder head

q	Removing and installing → Chapter

q	Reworking valve seats → Chapter

q	Reworking sealing surface → Fig.

q	Sealing transition points → Fig. and → Fig.

5 -	Valve guide

q	Checking → Chapter

6 -	Valve stem seal

q	Renewing → Chapter

7 -	Valve spring

q	Removing and installing: Cylinder head Removed: with -T20034B/1- installed: → Chapter, Renewing valve stem seals

8 -	Upper valve spring plate

9 -

Cotters

10 -	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

11 -	Inlet camshaft

q	Checking axial clearance → Fig.

q	Removing and installing → Chapter

q	Checking radial clearance with plastigage Wear limit: 0.1 mm

q	Run-out: max. 0.01 mm

12 -	Inlet camshaft bearing cap

q	Installation position and installation sequence → Chapter, Removing and installing camshafts

13 -	Double bearing cap

q	Lightly coat contact surfaces with -AMV 174 004 01- before installing

q	Must seat on dowel sleeves

q	Seal double bearing cap/cylinder head transition point, → Fig.

14 -	Exhaust camshaft

q	Checking axial clearance → Fig.

q	Removing and installing → Chapter

q	Checking radial clearance with plastigage Wear limit: 0.1 mm

q	Run-out: max. 0.01 mm

15 -	Exhaust camshaft bearing cap

q	Installation position and installation sequence → Chapter, Removing and installing camshafts

16 -

10 Nm

17 -

10 Nm

18 -	Drive chain

q	Before removing mark D.O.R. (installation position) → Chapter

19 -	Chain tensioner

q	Secure with -T20044- before removing → Chapter; Removing and installing camshafts

q	Seal hydraulic chain tensioner/cylinder head transition point → Fig.

20 -	Rubber/metal gasket

q

Renew

21 -

Gasket

q

Renew

22 -	Exhaust valve

q	With sodium filling

q	Observe notes concerning the scrapping of valves with a sodium filling → Fig.

q	Do not rework only grinding-in is permitted

q	Valve dimensions → Fig.

23 -	Inlet valve

q	Do not rework only grinding-in is permitted

q	Valve dimensions → Fig.

24 -

Oil seal

q	Lightly oil sealing lip of oil seal

q	Renewing → Chapter

25 -

Hood

q	For Hall sender

q	When installing note fixing arrangement

26 -

Washer

q

Conical

27 -

25 Nm

28 -	Hall sender -G40-

29 -

10 Nm

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 -T20020- t  Dial gauge Test sequence 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! Care must be taken when disposing of old sodium filled valves. They must be cut through in the centre of the stem with a hacksaw. When doing this they must be perfectly dry. 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 put in with the normal scrap.

Sealing transition points between double bearing cap and cylinder head –  Carefully apply a thin coat of sealant -D 454 300 A2- to both edges of sealing surfaces between double bearing cap and cylinder head -arrows- using a small screwdriver.

Sealing transition points between chain tensioner and cylinder head –  Carefully apply a thin coat of sealant -D 454 300 A2- to both edges of sealing surfaces between camshaft adjuster and cylinder head -arrows- using a small screwdriver.