Engine over speeding can be as a re

Engine over speeding can be as a result of down shifting an automatic or manual transmission in too low of gear for the current vehicle speed, operating the engine at a higher than designed engine rpm from aftermarket tuning and sudden drivetrain failure on a loaded engine causing unregulated engine rpm gains through inertia. As this failure can happen suddenly it typically leaves the condition of a relatively undamaged bearing and crankshaft journal, excluding collateral damage from the resulting high energy collision, but leaves the threaded end of the connecting rod bolts in the upper connecting rod assembly. This is possible from the bolts achieving their tensile stress point and break at the mating surface where the cap meets the connecting rod.