2. Measure the distance "a" between the end of the valve stem and the top edge of the cylinder head (fig. 3.14 a).
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 distance for lapping. For example, Measured distance 36.5 mm - minimum distance 35.8 = maximum allowable distance for lapping 0.7 mm.
The angles of the inlet valve seat are shown in Fig. 3.14 b, and the outlet valve seat angles are shown in Fig. 3.14 c.
Intake valve seat angles
Diameter a = 34.4 mm.
Maximum allowable distance for lapping b.
c = max 2.0 mm.
Z = Lower edge of cylinder head.
Valve seat angle α = 45°.
Upper correction angle β = 30°.
Lower correction angle γ = 60°.
Exhaust valve seat angles
Diameter a = 27.8 mm.
Maximum allowable distance for lapping b.
[The information is presented on the website: VWmanual]
c = max 2.0 mm.
Z = Lower edge of cylinder head.
Valve seat angle α = 45°.
Upper correction angle β = 30°.
Lower correction angle γ = 60°.
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