Laufbuchsen

Laufbuchsen, also known as cylinder liners or sleeves, are cylindrical inserts fitted into the bore of an engine cylinder block. Their primary function is to provide a wear-resistant surface for the piston to reciprocate against, protecting the more expensive cylinder block from direct contact and abrasion. This wear layer is crucial for maintaining engine performance and longevity. Laufbuchsen are typically made from materials with high wear resistance, such as cast iron alloys or hardened steel.

There are two main types of laufbuchsen: dry and wet. Dry laufbuchsen are pressed into a counterbore within the cylinder block and are cooled by the surrounding block material. Wet laufbuchsen, in contrast, are in direct contact with the engine coolant on their outer surface, allowing for more efficient heat transfer. The choice between dry and wet liners depends on the engine design, cooling system, and performance requirements. Laufbuchsen can be replaced if they become worn or damaged, a process often referred to as "reboring" or "sleeving" an engine, which is a common repair method to restore engine integrity.