Touareg V8-4.2L (AXQ) (2006)
Valve Seat: Specifications
Valve Seats, Refacing
Special tools, testers and auxiliary items required
‹› Depth gauge
‹› Valve seat refacing tool
Work procedure
‹› When repairing engines with leaking valves, it is not sufficient to rework or replace valve seats and valves. It is also necessary to check the valve
guides for wear. This is particularly important on high mileage engines --> [ Valve Guides, Checking ] See: Valve Guide/Testing and Inspection.
‹› 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 lifters can no longer be guaranteed and
therefore the cylinder head should be replaced.
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Remove camshafts --> [ Camshafts and Camshaft Adjusters ] See: Camshaft, Lifters and Push Rods/Camshaft/Service and Repair.
Maximum permitted refacing dimension is calculated as follows:
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Insert valve and press firmly against seat.
‹› If the valve is to be replaced as part of a repair, use a new valve for the calculation.
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Measure distance - a - between end of valve stem and upper edge of cylinder head.
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Calculate max. permissible reworking dimension from measured distance - a - and minimum dimension.
Minimum dimensions: