12 Valve Cummins KDP Information
Cracked camshaft gears and/or cracked gear housings are amongst the most common failure points when a KDP becomes dislodged and begins dancing around the complex system of gears keeping the engine running in sync. The best scenario following a KDP event is that the dowel pin gently falls to the bottom of the front cover, eventually settling [peacefully] at the bottom of the oil pan where it can rest indefinitely without concern (a screen on the oil pump eliminates the possibility of damage occurring should the pin find its way into the oil pan). The worst case scenario is that the dowel pin becomes lodged between the camshaft and injection pump gears, causing a chain reaction of destruction that includes the pistons meeting the valvetrain and ultimately a catastrophic, unrepairable engine failure.
While affecting all 12v engines, KDP related failures are most common on 1994 to 1998 model year trucks, which utilize the Bosch P1700 injection pump. The [more desirable] P-pump engines are thought to experience different harmonics in the gear train and front cover assembly than 1989 to 1993 engines equipped with the VE44 rotary injection pump. Due to the potentially hazardous nature of the KDP, we highly recommend installing a KDP prevention tab on all 12v engines to permanently eliminate any and all concerns.
KDP Tabs & KDP Disaster Prevention Kits
A KDP prevention kit is relatively inexpensive insurance against the possibility of a premature, catastrophic engine failure. It works by installing a small metal tab over the dowel pin using an adjacent bolt that secures the gear housing to the engine block. Installation of the tab is simple, straight forward, and intuitive. However it requires removal of the front cover, a relatively invasive and time consuming process for first timers. In reality, the procedures are much more intimidating than they are difficult. Some KDP kits include a replacement front cover gasket, while more affordable solutions reseal the front cover using RTV silicon. There is some evidence to suggest that using RTV silicon is advantageous to the factory replacement gasket and may provide a more resilient seal in certain instances.
For 1994 - 1998 model year Dodge Rams equipped with the 12v Cummins, we highly recommend the following the kit: 12v Cummins KDP Tab & Complete Installation Kit