21.1. Diagnostics of bearing failure.
1 Scratches.
2. Penetration of dirt into the bearing material.
3. Scratched by foreign inclusions.
4. The coating is worn off.
5. Lack of oil or incorrect clearance adjustment.
6. The coating has come off at the edges.
7. Hourglass effect.
8. Radial movement.
9. Radial movement.
10. Pits or shells.
11. Fatigue failures.
12. The sections are shiny (polished).
13. Incorrect installation.
2. Bearings are destroyed due to lack of oil, contamination and foreign particles, engine overload and corrosion. Regardless of the type of reason for bearing failure, it must be eliminated so that it does not appear in the newly assembled engine.
3. To check the bearings, remove them from the block, separate the caps, connecting rods and connecting rod caps, then place them on a clean surface in the same position they were in the engine. This will help you immediately identify defects in the bearings and the corresponding crankshaft journals.
5. Insufficient (or absent) oil may occur for a number of internal reasons. Excessive overheating (reduces the oil layer), overload (squeezes oil from the working surfaces of the bearing), as well as oil leaks or splashes (due to excessive clearances in the bearings, wear of the oil pump or too high engine speeds) - all this leads to an emergency lack of oil. Often, due to misalignment of the oil-conducting holes in the bearing housing, they become clogged; and this leads to oil "starvation" of the bearing, and as a result, to its damage. If the bearing has failed due to lack of oil, then usually in this case its material is pressed or rubbed off the steel base of the bearing.
6. Certain driving habits also affect the longevity of bearings. Full throttle at low speeds (engine overload) seriously overloads the bearings - this causes the oil film to be "squeezed". Such loads cause the bearing to bend, which leads to cracks in the working surfaces (fatigue wear). Eventually, the bearing material is torn off from the steel base in pieces. Driving very short distances also promotes bearing corrosion, since the engine does not get hot enough to evaporate the condensed water and corrosive compounds. These products collect in the engine oil, forming acid and deposits. Once the oil enters the engine bearings, the acid reacts with the bearing material and causes its corrosion.
7. Incorrect installation of bearings during engine assembly also leads to bearing failure. Too tight a fit of bearings will leave insufficient clearance for oil supply, which will cause their oil "starvation". Dirt and foreign inclusions that get on the bearing shell lead to stains and, subsequently, to failure.