Figure 3-22. Heat Dam.
overheat at these points and cause damage to
the cylinder walls In the form of rough streaks.
This condition is called scuffing. New piston
rings are coated with a porous material such as
graphite, phosphate, or molybdenum. These
materials absorb oil and serve to minimize
scuffing. As the rings wear In, the coatings
(3) Some piston rings are chrome plated.
Chrome-plated rings generally provide better
overall wearing qualities. They also are finished
to a greater degree of accuracy, which lets
them wear in faster.
Figure 3-23.Ring Gap
Figure 3-24. Figure 3-25. Staggered Ring Gaps