Traditional main bearing construction is based on a three-layer bearing made of a steel backing, a hard mid layer and a thin overlay of a soft material. The bi-metal bearing is constructed of only two layers, consisting of a steel backing with an inlay of an aluminium alloy. Typical bearing materials used in the construction of bi-metal bearings are a combination of the following materials: Tin, silicon, lead, copper and aluminium. The bearing material may sometimes be described as...

In previous articles on the subject of crankshafts, we have touched on the benefits of compressive residual stresses. Two methods by which this might be introduced have been discussed, these being nitride hardening (nitriding) and fillet rolling, although there are many others, some of which will be discussed at a later date. By imparting these residual stresses to the surface of the material, there is a large increase in fatigue strength, which gives a greater factor of safety against...