Piston Rings – Think You’ve Seen Them All?

Piston Rings – Think You’ve Seen Them All?

Most technicians are very familiar with compression and oil control piston rings, which are fitted into grooves on the outside diameter of a piston. In many diesel engines, however, piston rings aren’t just found on the piston. There is a type of piston ring that actually fits into the upper part of the cylinder liner itself. This unique type of piston ring is known as an “anti-polishing” ring.


In diesel engines, a small gap is formed between the outside diameter of the top of a piston (above the 1st compression ring), and the inside diameter of the cylinder liner. While the engine is running, carbon deposits will accumulate in this site. These deposits will ride along with the piston, wearing the cylinder liner wall. The anti-polishing ring serves to remove these deposits from the top of the piston. Along with reducing cylinder liner wear, anti-polishing rings also help cut hydrocarbon emissions.

Your truck’s engine could be equipped with anti-polishing rings. To find out more, you can consult Tractor-Trailer.net for more specific service information.