seat Workshop Repair Guides

SEAT Workshop Service and Repair Manuals

Removing and installing cylinder head > < Removing and installing crankshaft
5-cyl. injection engine, (4-valve), Mechanics
Servicing valve gear
Reworking valve seats

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

  • ◆ Depth gauge
  • ◆ Valve seat refacing tool

Work sequence

Notes:

  • ◆ When repairing engines with leaking valves, it is not sufficient to replace or renew valve seats and valves. It is also necessary to check the valve guides for wear. This particularly important on high mileage engines .
  • ◆ The valve seats should only be reworked just enough to produce a perfect seating pattern. The maximum permissible reworking dimension must be calculated before work is carried out. If the reworking dimension is exceeded, the function of the hydraulic tappets can no longer be guaranteed and therefore the cylinder head should be renewed.
  • ‒ Remove camshafts => Page 15-65.

The max. permissible reworking dimension is calculated as follows:

  • ‒ Insert valve and press firmly against seat.

Note:

If the valve is to be renewed as part of a repair, use a new valve for the calculation.

 
N15-0356
  • ‒ → Measure distance -a- between end of valve stem and upper edge of cylinder head.
  • ‒ Calculate max. permissible reworking dimension from measured distance and minimum dimension.

Minimum dimensions:

Short inlet valve

mm

31.8

Long inlet valve

mm

10.2

Short exhaust valve

mm

31.8

Long exhaust valve

mm

10.2

Measured distance minus minimum dimension
= max. permissible reworking dimension.

Example:


-

Measured distance
Minimum dimension

10.6
10.2

mm
mm

=

max. perm. rework dimension*

0.4

mm

    *)    The max. permissible reworking dimension is shown on illustrations for reworking valve seats as dimension "b".

 
N15-0357

→ Reworking inlet valve seat

a
b
c
d
r2
Z
α
β
γ

= 30.6 mm ø
= Max. permissible reworking dimension*
= 0.9...1.5 mm
= 35.0 mm ø
= Radius 2.0 mm ø
= Cylinder head lower edge
= 45 °valve seat angle
= 30 °upper correction angle
= 60 °lower correction angle

    *)    Calculating max. permissible reworking dimension => Page 15-62.

 
N15-0357

→ Reworking exhaust valve seat

a
b
c
d
r2
Z
α
β
γ

= 26.7 mm ø
= Max. permissible reworking dimension*
= 1.2...1.7 mm
= 29.0 mm ø
= Radius 2.0 mm ø
= Cylinder head lower edge
= 45 °valve seat angle
= 30 °upper correction angle
= 60 °lower correction angle

    *)    Calculating max. permissible reworking dimension => Page 15-62.

Removing and installing cylinder head > < Removing and installing crankshaft