If the paint remains around the entire circumference (360°) chamfers of the valve, the valve is concentric. Otherwise, replace the valve.
If the paint appears around the entire circumference (360°) valve seats, guide (sleeve) valves and valve seat are concentric. Otherwise, regrind the bevel.
Pic. 2.83. Permissible thickness of the contact patch of the valve seat
Make sure that the contact patch is located in the middle part of the valve face and has a width of 1.0–1.4 mm (pic. 2.83).
Pic. 2.84. Checking the contact spots of the chamfers of the valve seats
If the contact patch is too high, correct the chamfer using cutters with a taper angle of 30°and 45°. If the contact patch is too low, correct the chamfer with 75°and 45°taper cutters (pic. 2.84).