When there is a crankpin bearing failure, the heat input on the bottom dead center of the journal creates thermal stress. This results to crankweb to close itself and affecting the trueness of the crankshaft straightness. All crankshafts have run-out limits and in case this is exceeded, the run-out should be straightened. In some cases, this can naturally happened after heat treatment (annealing) because during annealing, the metal reaches the critical temperature so that the molecules are realigning and since the thermal stress is released, the crankshaft straightens naturally. But also, it is quite possible that an external application can be needed to solve this issue. This method is called peening. Matra offers peening and straightening of 4-stroke engine crankshafts.