Until recently, grey cast iron or ductile iron was the material of choice for automotive applications - today, steel is preferred over iron by more and more engine designers. Steel compression ring technology, pioneered by the former Perfect Circle group, has been used in heavy-duty applications for over 30 years. That know how has become essential to the design and engineering of today's automotive engines.

Steel piston rings offer higher tensile strength, higher yield strength, greater fatigue life, and greater hardness while still offering a lower ring mass. These factors lead to better stress resistance, reduced groove pound-out, longer service life, better conformability, superior oil economy, and superior blow-by control while still lowering friction.

Perfect Circle's CP-20™ ring sets have raised the bar of quality regarding piston rings - plus their ease of installation makes them the premier choice for Rebuilders everywhere. The CP-20 rings can withstand the harsh operating environments in today's engines. The CP-20 consists of a barrel-faced top compression ring for better seal and quicker break-in, a reverse torsional twist second ring for better oil control, and a new CP-20 design oil ring that is easier to install, chemically polished for better oil drain-back, and has a 20 degree ear angle to ensure side seal around the ring.

Piston ring specs are as follows:

• 1st Comp Ring: 1.5mm
• 2nd Comp Ring: 1.5mm
• Oil Ring: 3.0mm
• Standard Bore: 3.898"