Timing Case Dowel Pin
In the back of the timing gear case, there is an assembly index pin pressed into a hole. Some holes do not fit tightly around the pin and the pin can vibrate out of the hole, then fall into the gear train. The pin is then rattled around by the timing gears until it either falls into the oil pan, gets kicked out through the side of the timing case, or passes through gear train bending the camshaft and ruining the gears and case. A small number of 12 Valve engines
Response from Cummins:
The timing pin diameter from the supplier and the hole drilled for the pin, are designed to be 'press fit' dimensions. In some rare cases, the supplied timing pin dimension and the drilled hole dimension, may not provide the correct 'press fit'. During assembly line manufacturing, it is impossible to determine the amount of 'press fit' between the pin and the drilled hole, once the pin is installed into the bore.
A few of the pins have not had the correct 'press fit' in the drilled hole and have worked out of the hole. This does cause extensive damage to the gears and gear cover. The percentage of failure is very, very low and did not justify a major campaign of all engines. If an unexpected failure should occur during the warranty period of the engine, the repair will be handled under normal warranty practices.
Early in 1998 the gear cover was changed to a 'blind hole' design, which would not let the dowel pin move out of the bore. If you have a great fear of this pin coming out, we suggest discussing this issue with your local Dodge dealer or Cummins distributor, to determine the appropriate action in each situation.
The pin itself can be replaced if desired or Locktite can be used to hold it in place, without having to replace the pin or gear housing assembly.
Inspection and securing of the timing pin:
1. Remove the damper, pulley and gear cover from front of engine.
2. Tap on the dowel pin with a flat punch to insure that it is seated in the bore.
3. Clean all the oil from area with solvent and dry completely.
4. Apply some wicking type Locktite on the dowel pin and housing and let the Locktite cure.
5. Reinstall the cover with a new seal and gasket.
6. Reinstall damper and pulley.
We hope this helps you understand the dowel issue better.
Thank you for your interest in Cummins power or products. Please let us know if you need assistance in locating the nearest Cummins-authorized distributor or dealer. Please feel free to use our International Dealer Locator: found on the Customer Assistance page of the Cummins website.