Cummins 4BT – Edge Deterioration (Breakdown) Criteria

The area of edge deterioration should not be greater than the equivalent area of a 2 mm [0.079 in] circle within +
or -20 degrees of the nose of the cam lobe.

Outside of the + or -20 degrees of the nose of the camlobe, the areas of edge deterioration should not be greater
than the equivalent area of a 6 mm [0.236 in] circle.