Top Compression Rings

Top compression rings (UCRs – upper compression rings) control combustion chamber gases allowing the piston to transfer the energy of the expanding combustion gases, to the crankshaft. These rings also play a major role in the heat transfer process between the piston and cylinder wall. Our top compression rings come in a variety of coatings and four popular styles.

Top Compression Ring Types

Barrel Face Piston Ring Profile
Torsional Piston Ring Profile
Full/Half Keystone Piston Ring Profile
Rectangular Piston Ring Profile

Barrel Face

This common top ring profile has a convex face, enabling a higher ring face contact pressure, and can be symmetric or asymmetric. This profile results in improved combustion gas sealing and improved oil control versus a straight-faced ring. Coatings include: Plasma Moly, Chrome Manganese Phosphate, or Ceramic PVD.


This ring type is trusted for increased gas side sealing and better oil control. It may have barrel or straight face. Coatings include: Manganese Phosphate, Chrome and Plasma Moly.

Full/Half Keystone

Primarily used in diesel applications, the Full/Half Keystone type prevents carbon build up and ring sticking. It also creates additional surface area for side load bearing. Coatings include: Chrome, Ceramic Chrome, and PVD.


Rectangular type has no ID bevel. Sometimes seen in internal combustion engines, it is widely used in compressors and pumps.

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