⚙️ TECH THURSDAY ⚙️ The big end bush

Today in Tech Thursday: The big end bush

The big end bush is a component in engine technology and belongs to the plain bearings. It sits in the connecting rod eye and surrounds the piston pin. Its purpose is to allow the connecting rod to move smoothly and in a guided way on the piston pin. Lack of lubrication can lead to wear on the bush, which in the worst case may not only cause severe engine damage but also requires a complex repair, as the bush has to be mechanically fitted.

Modern big end bushes for highly stressed engines are usually manufactured from KS X20, a lead-free steel-brass composite material. This material is capable of withstanding the enormous mechanical loads inside the engine. The structure typically consists of a brass layer applied to a steel backing.

Other composite materials for manufacturing big end bushes include KS 646, KS S803, and KS S705.