It had nothing to do with the design of the dampener, but it had to do with its application. That style dampener is still used today on the Magnum engine with a lower rpm. When the 8.3 was first installed in the 1600 series, the rpm was cranked up to match the 400 series engines which was faster than the engine used in the Magnum. Tweaking the pump in the field to get to the high end of the rpm spec for better performance also didn't help. The new style viscous dampener will handle the extra rpm where the older rubber bonded style won't. That said, there are alot of the older ones still running in this area. We usually see 1 or 2 a year fail, which is a very small number considering that there are still many of those combines still around.