Page 7 of JE Pro Seal Catalog by JE Pistons

8 SECOND RINGS The most conventional second ring shape is a taper faced reversetorsional twist. The tapered face of the ring acts as a wiper that scrapes excess oil from the cylinder wall (fig. 1). It is important to prevent oil from entering the combustion process as this can lead to detonation which in turn increases carbon build up and raises both piston and oil temperatures. The chamfer machined in the back, under-side of the ring produces a twist in the ring, which enhances its cross-sealing properties. Second rings are also available from JE Pro Seal in the Napier or hook style ring face. This design is considered superior to a tapered face design as the hook shape actually channels oil flow back down the cylinder wall and away from the underside of the ring (fig. 2). OIL RINGS The function of an oil ring is to remove oil from the cylinder wall. In most cases, an oil ring is actually three pieces, consisting of two rails with an expander in between them. As an engines rotating assembly continuously slings oil and creates a heavy oil mist within the crank case, oil accumulates on the cylinder walls, crank, rods, and piston skirts. However, the oil film will tend to remain in contact with the cylinder wall as the piston slides across it, so a method of scraping and scavenging this oil is necessary to keep it out of the combustion chamber. While both the oil ring rails and the 2nd ring perform this scraping function, only the oil ring has a method for scavenging this oil. A three-piece mechanism all its own, the oil ring uses piston motion to create a pumping action which redirects accumulated oil to drain back holes or wrist pin oiling holes drilled in the piston. JE Pro Seal oil rings are offered in either high, standard or low tension versions. High and standard tension rings are most commonly used in street/strip wet sump style engines and engines using forced induction or bolt-on power adders. JE Pro Seal is the first to offer standard tension oil rings with a 3mm axial height. Low tension oil rings are most commonly used in dry sump applications. The advantage of a low tension oil ring is less friction along the cylinder wall, which generally leads to more power. Because the scavenging section of the dry sump system remove so much oil from the crank case and cylinder walls, low tension rings are sufficient to provide proper oil control. Most JE Pro Seal oil rings are equipped with chrome plated rails (non-chrome plated rails are also available). Titanium Nitride coating (TiN) of oil ring rails is also available as a custom option for any JE Pro Seal Oil ring. This coating provides additional wear resistance for extreme applications, has a very low coefficient of friction, and is compatible with Nikasil bores. JE Pro Seal Oil Rings are available with two different types of expanders. The F Type style expander (fig. 4) is most commonly used in low tension oil rings and features a wave shaped pattern that alternates between the top and bottom oil ring rails. The S Type style expander is more common in standard tension oil rings and uses holes in the humps (fig. 4) to provide an oil passageway to the back side of the ring and ultimately out through the oil drain back holes. In some instances, specifically in horizontally opposed cylinder orientation, a 2-piece oil ring is preferred. Two-piece oil rings are the original equipment ring for Porsche and are usually compatible with Nikasil bores. They consist of a cast iron M-shaped outer ring with spiral spring spacer inside (fig. 5). JE offers OE replacement ring sets with 2-piece oil rings in popular bore sizes for Porsche and other engines. Please call your JE sales representative for further information. NAPIER FACE RING FIGURE 2 TAPER FACE RING FIGURE 1 F TYPE OIL RING FIGURE 4 REAR ISOMETRIC VIEW S TYPE OIL RING 2-PIECE OIL RING FIGURE 5 REAR ISOMETRIC VIEW RING FUNCTIONS

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