The crankshaft bearing ring is mainly caused by the gap, and the phenomena and treatment are mainly embodied in the following aspects:
1) under normal circumstances, when the engine is running stable and noiseless, when the engine running speed suddenly change, boring boring, boring, knock, accompanied by vibration.
2) when the engine load changes, the noise is obvious. The higher the speed, the greater the noise.
3) when a single cylinder breaks fire, there is no change, and when the two adjacent cylinders cut off the fire at the same time, the noise will be obviously weakened.
Reason: 1) the clearance between crankshaft and shaft neck is too large.
2) northern Baotou Benz parts crankshaft and axial clearance is too large.
3) the crankshaft bearing cap bolts are loose.
4) Baotou North Benz parts crankshaft bearings and shaft lubrication is poor, resulting in bearing alloy ablation and fall off.
5) crankshaft bending deformation, crankshaft journal out of round.
6) the northern Baotou Benz parts crankshaft bearings and bearings relative rotation.
Diagnosis：
1) sound coming from the lower part of the cylinder close to the crankcase. The oil pressure drops obviously. The engine vibrates the throttle at low and medium speed, causing a pronounced and dull continuous knocking accompanied by engine vibration.
2) high speed engine, the body vibration is greater, while the oil pressure decreased significantly, but the gap between the bearing and the shaft neck is too large or the bearing alloy is ablated and detached
3) the misfire test of single cylinder has little change of sound, while the sound of the adjacent two cylinders is obviously weakened or disappeared when the fire is broken, and the crankshaft bearing of the two cylinders is sounded
4) high speed body vibration is large, oscillating shaking phenomenon, also issued heavy and larger “bang bang” knocking the crankshaft.
5) the sound increases as the temperature rises, and at high speeds the sound becomes tangled, possibly bent.