Volkswagen Workshop Service and Repair Manuals

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

• ◆ Depth gauge
• ◆ Valve seat refacing tool

Notes:

• ◆ When repairing engines with leaking valves, it is not always sufficient to reface or renew valve seats and valves. It is also necessary to check the valve guides for wear. This is 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.

Calculating max. permissible reworking dimension

• ‒ 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.

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

Minimum dimension:
     Inlet valve 35.8 mm
     Exhaust valve 36.1 mm

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

Example:

Engine codes 1Z, AHU, AEY, AFN, AVG, ALE

→ Reworking inlet valve seat

Note:

The 30 ° lower valve seat chamfer is necessary to ensure that the inlet channel flow characteristics are maintained.

→ Reworking exhaust valve seat

Engine codes 1Y, AAZ

→ Reworking valve seats

     1)     max. external diameter of correction cutter