High-pressure oil tank of DuPont™ Zytel® nylon for high-performance BMW motorcycle

The new BMW K 1200 S motorcycle, launched in September 2004, has dry-sump lubrication, developed for use in racing cars. This technology offers maximum operating safety even under extreme conditions, and it reduces motor height, as it does away with the oil-pan. To replace the oil-pan, a separate oil-tank of glass-reinforced DuPont™ Zytel® nylon acts as the oil reservoir. Developed by the Mahle Group of Stuttgart, this tank holds 2.8 litres of oil and is located in the triangle of the frame, just behind the motor and above the rear wheel. The motor develops 167 hp and has maximum torque of 130 Nm.

“The oil-tank for the K 1200 S is a critical part from a safety point of view,” comments Jörg Stange of Mahle’s OEM marketing department. “It must stay leak-proof in normal use throughout the lifetime of the motorcycle. If oil were to leak from it and drip onto the rear wheel, severe falls could be the result. That is why we chose Zytel® 70G35 HSLRA4, a resin tested and proven in our own company.”

This DuPont 66-type nylon, reinforced with 35 percent glass fibre, offers high stiffness and strength, so that the tank withstands the extremely high internal pressures created when the motor starts up with an overfilled tank. “Thanks to the melt’s easy-flow properties, this Zytel® type can be processed very cost-effectively,” Stange adds. “That is particularly important for this oil tank, because we produce the cover and the main body together in a single tool. The good flow characteristics also contribute to the part’s high-class surface finish, which is a requirement for this highly visible part.” The resin chosen by Mahle offers very good resistance to a broad range of chemicals, and to hot oil in particular; it is suitable for use at continuous temperatures from –20 °C to +140 °C.