Valve seat machining (VW Polo 3)

1. Insert the valve and press it firmly against the seat.

2. Measure the distance "a" between the end of the valve stem and the top edge of the cylinder head (Fig. 7.25).



3. Calculate the maximum allowable distance for lapping.

• Minimum distance for inlet valve: 35.8 mm.
• Minimum distance for exhaust valve: 36.1 mm.

4. Measured distance - minimum distance = maximum allowable lapping distance. For example, Measured distance 36.5 mm - minimum distance 35.8 mm = maximum allowable lapping distance 0.7 mm.

The seat angles of the inlet valve are shown in Fig. 7.26, and the outlet valve - in Fig. 7.27.





Intake valve seat angles

• Diameter a: 35.7 mm.
• Diameter b: 1.6 mm.
• 45° - Valve seat angle.
• 30° - Correction angle.

Exhaust valve seat angles

• Diameter a: 31.4 mm.
• Diameter b: 2.7 mm.
• 45° - Valve seat angle.

[The original can be seen on the portal: www.VWManual.ru]