2003/07/01 Caterpillar

Engine: Commercial

3500 Family All

Caterpillar Products:

3500 Family Generator Sets and Power Modules

The quality and the service life of Cat Remanufactured Camshafts are equivalent to the quality and to the service life of new camshafts.

Remanufacturing Processes

Camshafts for 3500 Engines are remanufactured with the same grinding process that is used in the manufacture of new camshafts.

For remanufacturing, each individual lobe is precisely measured. Only the minimum amount of material is removed during the grinding. This process ensures that the maximum depth of the case is maintained.

Dimensionally, remanufactured camshafts are equivalent to new camshafts. The remanufactured camshafts have the same specifications and tolerances as new camshafts for these characteristics: size of lobe, profile of lobe, hardness and depth of case.

The metallurgy of remanufactured camshafts is equivalent to new camshafts. The remanufactured camshafts are inspected with the same methods as new camshafts for evidence of burns from grinding, for cracks, and for imperfections on the surface. Detailed inspections are performed for each camshaft.

Metal Fatigue

Metal fatigue is indicated by cracking and/or by spalling (chipping or flaking) of the surface. Fatigue on the surface indicates that the camshaft has been operated at loads that exceeded the limit of the metal's strength for resisting fatigue. A camshaft that has fatigue on the surface will fail.

The presence of metal fatigue is identified during manufacture by the magnetic particle inspection. Any camshaft that exhibits signs of metal fatigue is scrapped.

Some 3500 Engines have exhibited fatigue in the lobe for the fuel injector's lifter. The chance of this occurrence is equal for remanufactured camshafts and for new camshafts. This problem has been addressed by design changes to the profile of the lifter's crown. Because Caterpillar has confidence in the reliability of remanufactured camshafts, the remanufactured camshafts have been specified in the required parts for the Product Support project.

Reliability of Camshafts

A limited number of remanufactured camshafts for 3500 Engine parts have only been available since June 2002. In October 2002, remanufactured camshafts were included in the parts for remanufactured 3500 Engines. Because of the limited number, the remanufactured camshafts have been seeded with new camshafts for distribution of parts and for remanufactured engines.

Because of the limited availability of remanufactured camshafts and of the limited data from the field, a validated prediction on the reliability of the remanufactured camshafts is pending. However, the initial data that has been gathered does not indicate any difference between the reliability of remanufactured camshafts and new camshafts.

Caterpillar is confident in the quality and in the reliability of Cat Remanufactured Camshafts.