HOLDER-TOOTH 3970399 - Caterpillar

Truck EnginesDescription of Change: A new piston group is used in 1693 Truck Engines. The new group uses a piston body with an improved cast iron band for the keystone type piston rings. The location of the band in the piston body is the same as in the former 9L6054 Piston Group, but the shape of the band is changed from taper sides to flat sides for increased strength. At the same time, a change in core design makes the piston stronger around the top (crown area).Adaptable As: Direct replacement. The new 9N2875 Piston Group (Basic) is a direct replacement for the former 9L6054 Piston Group (Basic) which is canceled. The 4N5619 Piston Ring Group (Replacement) is not changed. The new piston is a little heavier than the former piston. The difference in weight is not enough to cause engine damage, but it can possibly cause a small increase in vibration if the new and former pistons are mixed in the same engine.In addition to the use of the new 9N2875 Piston Group for replacement of the 9L6054 Piston Group, the new group can be used for replacement of the earlier 1P435, 9S2266, 7N738 and 7N739 Piston Groups in all 1693 Engines. All of these earlier pistons had rectangular (square) type piston rings (in comparison with the improved keystone type rings), and installation of the later design pistons and rings will give longer service life. The recommendation is that the 7N738 and 7N739 Piston Groups not be installed for service replacement.