Plastic tensioners for the Cayenne.

The timing change tensioner for the Porsche Cayenne is actually a plastic assembly, not metal as is often the case. Specifically, the component, produced by German suppler IWIS (www.iwis.com/en), is a two-piece assembly. There is a wear-resistant grade of Stanyl (TW341) for the top layer that presses on the timing chain and a high-stiffness grade of the polyamide (TW241F10) used for the tensioner base. "According to Ton Vet, application development manager for Stanyl at DSM Engineering Plastics (Evansville, IN; www.dsm.com), "In the IWIS design, the tensioner base can be made as stiff as needed by using high-stiffness materials. At the same time, the top layer can offer a non-abrasive surface to the chain for maximum life with minimum wear and friction." The top layer comes out of the mold with a smooth finish, including with the gears to guide the chain; the bottom layer is molded in its final shape, including all reinforcing ribs and mounting and pivot points for assembly.

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