earlier, there are three basic types of engine bearingsconnecting rod bearings,
crankshaft main bearings, and camshaft bearings. The backing material (body of the bearing
that contacts stationary parts) for engine bearings is normally steel. Softer alloys are
bonded over the backing to form the bearing surface. Any one of three basic types of metal
alloys can be plated over the top of the steel backingBabbitt (lead-tin alloy),
copper, or aluminum (fig. 3-73).
These three metals may be used in different combinations to design bearings for either
light-, medium-, or heavy-duty applications. The engine designer selects the combination
of ingredients that will best suit the engine.