Compression Rings

Federal-Mogul offers various types of compression rings — all designed to seal the combustion chamber from the crankcase (blowby) and transfer heat from the piston to the cylinder. These rings also assist in controlling engine oil consumption, which has a strong influence on exhaust gas emissions.

Scraper Rings

Most Federal-Mogul scraper rings have a step recessed into the bottom outer face, which assures extremely effective oil scraping and increases the unit pressure. Additionally, the step relief causes a positive twist that, without gas pressure, brings the periphery into bore contact with only the very edge of the step. The volume created by the step is beneficial in allowing large amounts of oil to be stored.

Oil-Control Rings

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Federal-Mogul offers a wide variety of two-piece and three-piece oil-control rings to suit a vast range of customer needs. Two-piece oil-control rings are used in diesel and some automotive gasoline applications. The design of a two-piece oil-control ring consists of a cast iron or profiled steel ring body and a coil spring. The spring is a cylindrical coil spring made from heat-set resistant spring steel, and it acts uniformly around the entire ring circumference.

For most gasoline applications, Federal-Mogul utilizes three-piece oil-control rings. The design of three-piece oil-control rings consists of two thin steel rings (rails) and an expander-spacer, which holds the rails at the required relative axial distance while simultaneously pressing them against the cylinder wall.