SEAT Workshop Service and Repair Manuals

Valve seats: Reworking   Note t  The valves can not be reworked. They may only be seated (ground) until a clean thrust tread is achieved. t  Before grinding the valves, calculate the maximum reworking measurement possible → Anchor . t  Check the valve guides → Chapter. If the wear limit is exceeded, redo the measurement using new valves. If the wear limit is still exceeded, replace the cylinder head t  If the reworking dimension is exceeded, hydraulic valve compensation can no longer be guaranteed and the cylinder head should be renewed. Maximum permissible reworking dimension: calculation –  Insert valve and press firmly against valve seat.   Note If the valve is to be renewed as part of a repair, use a new valve for the calculation.

–  Measure the distance -a- between the end of the stem and the upper edge of the cylinder head. –  Calculate the maximum reworking measurement starting from the measured distance -a- and the minimum measurement. l  Minimum inlet valve dimension: 43.4 mm l  Minimum outlet valve dimension: 43.2 mm Measured distance minus minimum dimension = max. permissible machining dimension.

Minimum measurement for the intake valve:
	Measured distance-a-		44.1 mm
–	Minimum dimension		– 43.4 mm
=	Max. permissible reworking dimension		= 0.7 mm

Note If the maximum permissible reworking dimension is 0 mm or less than 0 mm, repeat the measurement with a new valve. If the maximum reworking dimension continues to be 0 mm then replace the cylinder head.

To rework the intake valve seat

Dim.		Inlet valve seat:
Ø a	mm	35,7
b	mm	1,6
45°		Valve seating angle
30°		upper correction angle

Note The inclination of 30 ° of the valve seat is essential to avoid turbulence in the inlet canal.

To rework the exhaust valve seat

Exhaust valve seat:
a	=	Ø 31.4 mm
b	=	2.7 mm
45°	=	Valve seating angle