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Multi-Piece Oil Control Rings
Two-Piece Oil Control Rings

Two-piece oil control rings consist of a cast iron or profiled steel ring and a coil spring. The spring is a cylindrical coil spring made from heat-set resistant spring steel and it acts uniformly around the whole of the ring circumference.
The retaining groove for the coil spring may be semicircular or V-shaped. The coil spring groove has the effect of reducing the moment of inertia. Where greater durability is required, such as in diesel engines, the springs are centerless ground, sometimes additionally wound more tightly at the ring gap and in many cases sheathed in a Teflon tube in the ring gap region. These features have the purpose of reducing secondary wear between the spring and ring.

In order to prevent oil from accumulating between the two outer lands, drainage holes are provided. These can be either circular or slotted. For a long time the slotted hole was preferred but today round holes are again being used increasingly. The drilled rings have better breaking strength than the slotted type, offering greater safety in assembly especially for narrow width rings. Additionally, drilled rings have a more even outer contour, which assures better oil scraping. The cast iron rings described below can all be produced optionally with drilled or slotted holes.

Coil Spring Loaded Slotted Oil Control Ring::
A slotted oil control ring with two outer lands, the sides of which are parallel to one another. Compared to the slotted oil control ring described above, this ring additionally has a groove on the inside diameter to accommodate the coil spring.

Coil Spring Loaded Bevelled Edge Oil Control Ring::
Consists of a ring similar to the bevelled edge ring, but has an additional groove for the coil spring.

Coil Spring Loaded Double Bevelled Oil Control Ring::
Like the double bevelled ring, but with a groove to hold the coil spring.

Coil Spring Loaded Bevelled Edge Oil Control Ring with Chromed, Profile Ground Lands::
The wear coating gives the ring high long-time stability and makes it particularly suitable for operation mainly in diesel engines. The profile grinding of the lands allows close tolerances to be achieved on these critical working surfaces.

Nitrided Profiled Steel Ring::
A bevelled edge ring made from a high-chromium profiled steel. Wear protection is provided by nitriding the ring all over. Like the chromed bevelled edge ring, this ring is chiefly used in diesel engines. Oil drainage is provided by means of punched holes.


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