Is the big engine bushing damaged and the cause of the big failure the flywheel housing?


Release time:

2022-08-08

The vehicle flywheel housing connects the engine and transmission, external crankcase, starter, oil pan and built-in flywheel assembly, and plays the role of connecting the body, protecting and carrier. It bears part of the weight of the gearbox, protects the clutch and flywheel, and is also a supporting part of the engine. Its processing quality directly affects the performance of the engine. After replacing the flywheel housing, the national five-car accelerator is unstable, the speed drops, and the fault code reports that the crankshaft signal drifts or is lost. Check for problems directly after playing the waveform. Directly disassemble the large bushing, open a large bushing, and find serious wear. Then replace the valve body, bushing and crankshaft, and repair the engine.

The vehicle flywheel housing connects the engine and transmission, external crankcase, starter, oil pan and built-in flywheel assembly, and plays the role of connecting the body, protecting and carrier. It bears part of the weight of the gearbox, protects the clutch and flywheel, and is also a supporting part of the engine. Its processing quality directly affects the performance of the engine. After replacing the flywheel housing, the national five-car accelerator is unstable, the speed drops, and the fault code reports that the crankshaft signal drifts or is lost. Check for problems directly after playing the waveform. Directly disassemble the large bushing, open a large bushing, and find serious wear. Then replace the valve body, bushing and crankshaft, and repair the engine.

飞轮壳

During the use of the vehicle, the flywheel housing often cracks. The root cause of the crack is that the flywheel shell is subjected to abnormal vibration or torsion, resulting in stress concentration at the weak point. When the stress exceeds its strength limit or fatigue limit, the flywheel housing will crack. After the flywheel housing is broken, the coaxiality of the crankshaft and the transmission shaft 1 will be damaged, causing the clutch and starter to work abnormally.

The specific reasons for the cracking of the flywheel housing are complex, which are often the result of the comprehensive influence of the defects of the automobile engine, transmission system, frame and other parts.

The common causes of flywheel housing damage are as follows:

① The fastening bolts of the flywheel housing are loose.

② The axial or radial clearance of the crankshaft is too large.

③ The coaxiality of the crankshaft and the flywheel housing is out of tolerance.

④ The balance of the gearbox components is out of tolerance.

⑤ Improper manufacturing, processing or assembly.

⑥ Engine bracket failure.

⑦ Frame deformation.

Improper use.

In summary, there are many reasons for the cracking of the flywheel housing. However, in practice, it is common that the flywheel housing is damaged caused by the dynamic balance of the crankshaft and the clutch assembly, the shape and position of the flywheel housing, the imbalance of the drive shaft and the deformation of the frame. In order to prevent damage to the flywheel housing, what should be paid attention to in daily use and maintenance.

flywheel housing maintenance matters needing attention:

① During maintenance, check the static balance of the crankshaft and flywheel, and the balance of the flywheel and clutch pressure plate assembly according to the technical requirements. Be careful not to omit, install less or misassemble heavy.

②Install the flywheel, clutch and flywheel housing in strict accordance with the technical requirements to ensure that the coaxiality of the flywheel center line, crankshaft center line, flywheel housing center line and transmission shaft 1 is within the allowable range.

③ When installing the flywheel housing, the positioning pins should be aligned. The joint surface between the flywheel housing and the engine body should be flat. The fixing bolts of the flywheel housing are made of alloy steel. The bolt heads are marked with cast rings. Wrong installation is not allowed, and the bolts should be tightened alternately in the specified sequence and torque.

④When the crankshaft bearing clearance and crankshaft axial clearance are too large, the main bearing and thrust plate should be checked or replaced and adjusted.

⑤When assembling the drive shaft, pay attention to the arrow mark and do not install it in the wrong position to avoid shaking; if the drive shaft is bent, it should be adjusted, and the bearing and horizontal shaft should be replaced when they are worn and loose.

⑥ The engine bracket should be firm and reliable, the connecting bolts should be tightened if they are loose, and the support pad should be replaced if it is cracked, deformed or weakened.

⑦ Regularly check the tightening of the transmission system and flywheel housing bolts, and tighten them in time if they are loose.

⑧ Drive in strict accordance with the operating procedures, avoid overspeed and overload, and pay attention to driving safety.