Diesel engine connecting rod bolts are disposable, not allowed to repeat use. If the repeated use of the connecting rod bolt, bolt force due to the larger, elongated, extremely easy to cause the bearing due to lack of strength and bolt rolling tile burning accident; at the same time because the fastening lack of strength, bearing and crankshaft clearance increases, resulting in low oil pressure, resulting in excessive wear of the bearing and burning accident. Diesel engine, diesel engine, connecting rod impact load larger than ordinary diesel engine, Baotou Benz accessories connecting rod bolts repeated use can easily lead to fracture, broken engine cylinder body, causing the engine to scrap. Some units, although the replacement of the connecting rod bolts, there have been broken fault, there are individual engines in operation suddenly broken connecting rod bolts.
Causes of failure:
The assembly when tightening torque is too large, uneven force. Because the assembly is not strict with torque wrench, the tightening torque and do not quite understand, think more compactly as possible; fastening connecting rod bolts by boosting rod long, tightening torque is too large, exceed the yield limit of bolt material, the connecting rod bolts to yield deformation, the impact load due to excessive elongation fracture. It should be stressed that the Guangzhou must according to the standard screw bolt connecting rod, do not think that the more tight, the bigger the better strength.
The connecting rod of diesel engine can be divided into various levels, and it should be paid attention to not changing the connecting rod with different grades in the overhaul. If not carefully in the maintenance of the connecting rod cap due to sloppy mess, wrong attire, will cause the big surface combined with non close, during the engine operation will cause the connecting rod cap connecting rod bolts loosening caused fracture. Diesel engine connecting rod for oblique mouth, oblique angle was 45 degrees, and the connecting rod cap connecting rod with 60 OC with serrated positioning structure, this structure has the characteristics of close fitting, accurate positioning, reliable and compact structure. If the repair will confuse the connecting rod cap and wrong loading, is bound to cause the joint tooth location is not good, extremely easy to cause the engine in the connecting rod cap loose, resulting in fracture of the connecting rod bolt.
The diesel engine failure speed fault or a piston in a cylinder. In the operation, the connecting rod bolt snapped. If the engine speed of the fault occurred in the use of the engine, to do a comprehensive inspection, the best replacement of the connecting rod bolt; if the individual cylinder in operation appeared more serious in the cylinder, replacing the cylinder piston assembly should also replace connecting rod bolts.
The material, processing defects and heat treatment process problems can also cause the connecting rod bolt fracture during engine operation.
Preventive measures:
In each run 12000km two level maintenance, Baotou Benz accessories should remove the oil pan of the engine, check the engine bearing is used, if it is found that the individual bearing clearance is too large, should be replaced, the replacement should also replace the connecting rod bolt. Usually run if the engine is found to run unstable, there are different sounds, but also timely parking checks.
The repair in response to each new replacement of the connecting rod bolt for examination, should pay attention to the head of the bolt, screw thread guiding parts, each part is a crack or dent, tooth shape and pitch thread is abnormal, the abnormal situation should be resolutely not.
The connecting rod cap assembly, according to the standard application of torque wrench, tighten, prevent excessive torque, small.
The selection plant for the production of Baotou Benz accessories connecting rod bolt.