Why diesel engine connecting rod bolt is easily broken?

Connecting rod bolt is mainly used for fastening two parts with hole, but only for the organic rod bolt, which is a single-use, do not allow re-use, re-use connecting rod bolts if, due to force large, elongated bolt, can easily cause the pad due to lack of power occurs roller bolts tile bush-burning accident; and because of insufficient tightening force, with the gap pad and the crankshaft journal increases, resulting in low oil pressure, resulting in bush excessive wear occurs bush-burning accident.

      While the diesel engine for diesel engine connecting rod by a greater impact loads than ordinary diesel in many large, repeated use can easily lead to the connecting rod bolt fracture, broken engine block, causing the engine scrapped. Although some units replace the connecting rod bolts, there have been a fault rupture, individual engine running suddenly broken connecting rod bolt.

      Why diesel engine connecting rod bolt is easily broken its main causes are the following four?:

      1, the assembly tightening torque is too large, uneven force. Since there is no strict assembly equipped with a torque wrench, tightening torque and specifically I do not understand that the more compact the better; connecting rod bolts fastening longer afterburner rod, tightening torque is too large, more than the bolt material yield limit, so that the connecting rod bolt yield deformation occurs, so that under the action of impact load due to excessive elongation of fracture. It should be emphasized that, according to a certain standard tightening rod bolts, do not think that the more tightly force the bigger the better.

      2, connecting rod of the diesel engine at a variety of levels, in the maintenance should be careful not to change with different levels of link. If the maintenance due to careless careful not to confuse the connecting rod cap, the wrong equipment will cause connecting rod combined with the surface does not close, the engine is running will cause the connecting rod cap loose and cause breakage of the connecting rod bolts. WD615 series diesel engine connecting rod oblique incision type, chamfered angle is 45 °, the connecting rod cap and connecting rod 60 ° binding surface with serrated positioning structure, which has a close fit, accurate, reliable, compact Features. If the repair will confuse the connecting rod cap, the wrong equipment, it will inevitably lead to poor positioning combined with jagged surface, can easily cause the engine at work connecting rod cap loose, resulting in broken connecting rod bolt.

      3, diesel or Runaway occurred in the cylinder piston burned fault in the operation of the connecting rod bolt pull off. If the engine appeared in use coaster failure to deal with the engine to do a comprehensive inspection, it is best to replace the connecting rod bolts; if individual cylinders in operation there have been more serious pull cylinder, replace the cylinder when the piston assembly should also link replace the bolt.

      4, material problems, processing defects and heat treatment process also cause problems connecting rod bolt fracture occurs during engine operation.