Connecting Rod Failures

 Connecting Rod Failures On A Large Four-stroke Diesel Engine Caused By The Dynamic Interaction Between The Crankshaft And Connecting Rod

While investigating a catastrophic failure of connecting rods in a medium speed four-stroke engine that occurred without any warning, a simple explanation for the problem in the form of hydrolock was proposed by several investigating parties. The rod was found to have bent before breaking into two parts. Similar cases have been reported in the past where the end result was either a bent connecting rod and/or complete failure of the connecting rod as in this case. The theory of hydro- lock has traditionally been proposed in most cases of connecting rod failures and this theory has been widely supported by engine manufacturers. In this case, a thorough investigation proved that hydrolock could not have occurred, as there is not enough energy in the engine at start to bend the rod and also there are safety devices installed on the engine to avoid hydrolock.