Reasons for engine bearing locks the shaft

“Engine bearing locks the shaft” is a serious failure for engine, generally refers to a serious dry friction between crankshaft and main bearing/con rod bearing supporting engine rotation due to loss of oil, and form high temperature in surface, shaft journal and engine bearings mutual sintering bite deadly, which causes the engine can not rotate.

“Engine bearing locks the shaft” more than 95% are mechanical failures, usually due to

1. Quality of crankshaft and engine bearing is bad, the axis and the engine bearing surface finish is poor, especially the overhaul replacement vehicles bearing shell, overhaul of the grinding shaft tile work fine enough, engine bearing on the rear axle, with bad cooperation, difficult to form the oil film interface is too small, and there is gap on the back, alloy and engine bearing can’t completely loose fit closely and cylindrical, covering oil hole wall form dry friction causes oil supply disruptions.
2. Main bearing and con rod bearing installation is not correct, improper clearance adjustment, contact area is too large or too small, will make the shaft and the engine bearing contact surface difficult to form an oil film. Sometimes the torque of the strong bolt of engine bearings is too small, and engine bearings are loosened for a long time, the gap change will also affect the lubrication.
3. The gear of the oil pump suffers serious friction loss effect, the oil supply pressure decreases, and the oil is difficult to supply to the specified lubrication position, resulting in dry friction of engine bearing.
4. The oil passage is blocked by dirty impurities, which blocks the oil leading to the crankshaft and causes dry friction of engine bearing.
5. Oil pipeline leakage, oil circulation supply system pressure drop, oil is difficult to supply to the specified lubrication position, forming dry friction.
6. When the cold car starts the throttle, the oil has not yet been pumped to the engine bearing when the low temperature is more viscous, and engine bearing surface has formed an instantaneous high temperature, resulting in metal phase melting.
7. Engine is seriously overloaded, and there are long low-speed and high-torque working conditions. Because engine speed is low, the oil pump speed is also low, and the oil supply is insufficient, while high temperature is formed between the shaft and the tile, resulting in locking.