SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | 4 cylinder Injection engine (Autogas) | Engine cylinder head, valve gear | Servicing valve gear

Valve seats: reworking

Special tools and workshop equipment required

Gauge

t	Valve seat re-facing tool

Note

t	When repairing engines with non airtight valves, it is not enough to reface or to replace the valve seats and the valves. It is particularly important on high mileage engines to check the valve guides for wear.

t	The valve seats should only be reworked just enough to produce a good seating pattern. Before re-facing, the max. allowable re-facing value must be calculated. If the reworking dimension is exceeded, hydraulic valve compensation can no longer be guaranteed and the cylinder head should be renewed.

Calculate the maximum permissible reworking level as follows:

–	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.

Minimum dimension: Inlet valve 31.7 mm, Outlet valve 31.7 mm

Measured distance -a- minus minimum dimension = max. permissible machining dimension.

Example:

	Measured distance -a-	32.0 mm
-	Minimum dimension	31.7 mm
=	Max. permissible reworking dim. → Remark	0.3 mm

¹⁾	The maximum permissible reworking dimension is shown on illustrations as dimension „b“ .

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