Contents: Foreign inclusions ↓ Incorrect assembly ↓ Overload ↓ Incorrect installation ↓ Lubrication ↓ Corrosion ↓
Foreign inclusions
Babbitt insert with inclusions of mechanical rolling products. Microsection with inclusions
Microsection with grooves. Copper-coated insert with grooves made of cast iron particles
Aluminum insert with inclusions from glass beads. Microsection in case of using glass beads
Insert with damage caused by dirt on the back of the insert
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 by the short arc of contact
Polished and populated back sides are the result of improper seating in the mounting hole
The result of an improperly installed lid, one that is upside down or one that is displaced
Overload
The result is increased idle speed, which leads to the inability of the oil film to support the applied load
Damage to the upper bearing shells of the connecting rods caused by engine overload; lower main bearing shells (not shown) have similar defects
The damage shown on these upper and lower connecting rod bearing shells is caused by the engine running under load at high speeds
Incorrect installation
The severe wear shown in the center decreasing towards the edges is caused by deformation of the crankshaft
Evenly distributed scratches are caused by poor quality surface treatment of the crankshaft
The V-shaped nature of the imitations is caused by the bend of the connecting rod
The damage on one edge of this pair of bearings is caused by the taper of the seat hole
Lubrication
Result of starting the engine with a lube base: the bearings shown on the left are the farthest from the oil pump and have the most damage
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 poor maintenance, operation at too high or too low temperatures, or poor quality oil or fuel
Microsection for cavitation. Example of cavitation - surface erosion caused by pressure changes in the oil strip
Result of increased axial pressure or insufficient axial clearance
A bearing that operates with oil dilution, which is caused by increased gas blow-by or enriched mixture