Scuffing can sound the death knell for two-stroke engines. For it is the breakdown of the lubricant film or stuck piston rings which left unchecked may have catastrophic results. Germany’s CM Technologies has developed a scuffing sensor and we spoke to the company’s managing director Matthias Winkler about how it works.

“There is no system to detect scuffing at an early stage. The only thing which is around is a cylinder liner wall temperature measuring device,” says Winkler adding that given the heat produced in the combustion chamber, this is far from an ideal solution.

Scuffing only impacts two-stroke units because, explains Winkler, of the much slower movement and the very long stroke. This means the lubrication film is very long on the liner wall and needs to stay there while on four-strokes with 600 RPMs or 900 RPMs it’s permanently lubricated. The pistons in a two-stroke engine move very slowly over large distances with lubrication challenges and the lubrication can break.