Types of Piston Ring and Piston Ring Maintenance


We have all seen pistons, which are generally cylindrical engines that goes back and forth, in the bore, due to the force produced during a specific combustion process. Now, one of the main parts of the piston is, the piston ring which is a ring like structure which gets fitted in to the groove of the outer diameter of the piston in an interchanging engine, such as a steam engine. Generally, these piston rings are of three types, and these types are generally based on their function and usability.

Marine engines, which needs to serve to a higher capacity generally has all the three types of piston ring, with little or no difference in their appearances. While, the smaller marine engines generally contain any one type of piston ring, based on the function it would be doing.

In this article, we will predominantly discuss about the types of piston rings, and then talk about their maintenance as well.

  • Compression Rings-: Since, the main force or energy of the piston comes from a combustion process, it is the need of the hour to stop the gas from leaking. The Compression rings basically gets fitted at the top most grooves of the piston, and basically stops the gas leakage. Another function of the compression ring, is that it also transfers the heat energy from the piston to the piston walls.
  • Intermediate Rings-: The function of the intermediate rings is to shear the extra oil from the oil left by the oil ring, and use it for lubrication of the compression ring. At the same time, it also helps the compression ring to transfer the heat from the piston to the piston walls. It is positioned just below the compression ring, in the middle grooves of the piston.
  • Oil Control Rings-: The oil control ring, gets fitted in to the lower level grooves of the piston, and as the name suggests, generally controls the oil which passes up or down the cylinder walls. So, generally the work of these rings is to scrap the extra oil from the liner, and get it back to the crankcase again, and also to use the extra oil to lubricate the liner. Moreover, at the same time, the oil control rings also stop the oil to pass anywhere other than the face of the ring or cylinder.

While we are done with discussing the types of piston rings, now is the time to talk about some tips pertaining to the maintenance of the piston ring.

During Routine Inspection

Routine inspection is done for the piston rings, since, it is imperative to check for the freeness of the rings, since, they can get stuck due to depositions of carbon. Depositions of carbon can break the liner, which might cause a lot of damage to the system.

During Major Overhaul

Major overhaul is done only when the piston rings are stuck on the grooves, or there is a large gap between the ring and groove, due to the wear of normal day to day usage. A major overhaul requires the rings to be changed completely and new set of rings to be installed.

Since, there is a huge chance of carbon deposition due to rough usage, during a major overhaul the carbon depositions are cleaned off before installing a new set of rings.

Piston Rings, or predominantly Pistons has got a huge application in today’s industry. Knowing these facts and information about pistons will surely help a person, who works in the industry.