Foreign inclusions
Babbitt insert with inclusions of products of mechanical running. Microsection with inclusions
Microsection with grooves. Copper-plated liner with grooves made by cast iron particles
Aluminum insert with glass shot inclusions. Microsection in the case of using glass shot
Earmold with damage caused by dirt on the back of the earmold
Incorrect assembly
The result of installing the lower liner instead of the upper one is the impossibility of oil passage
Increased radial clearance is visible in the short arc of contact
Polished and populated backs are the result of a misfit in the bore
The result of installing an improper cover, turning it over or moving it
Overload
The result of increased idle speed, which leads to the inability of the oil film to support the applied load
Damage to the upper connecting rod bearing shells caused by engine overload; lower main bearings (not shown) have similar defects
The damage shown in these upper and lower connecting rod bearing shells is caused by running the engine under load at high RPM
Wrong installation
Shown severe wear in the center with decreasing towards the edges is caused by deformation of the crankshaft
Evenly distributed scratches are caused by poor surface finish of the crankshaft
The V-shaped character of the imitations is caused by the bending of the connecting rod
Damage along one edge in this pair of bushings is caused by the taper of the mounting hole
Lubricant
Result of starting the lubrication base engine: the bearings shown on the left are farthest from the oil pump and have more damage
The result of low oil supply or oil «starvation»
Severe wear due to insufficient radial clearance
Corrosion
Microsection for corrosion. Corrosion is the result of acid attack on the bearing shell, usually caused by improper maintenance, operation at too high or too low temperatures, or poor quality oil or fuel
Microsection for cavitation. An example of cavitation is surface erosion caused by pressure changes in the oil slat
Consequence of increased axial pressure or insufficient axial clearance
Bearing operating with oil dilution caused by increased gas breakthrough or enrichment of the mixture