Usage:
D348, D349 Engines;
641B, 650B, 651B, 657B, 660B, 666B, 772, 776, D10 Tractors;
773, 777 Trucks;
992 Loaders
Description of Change: A change has been made to the rod and piston group used in the above models. A new basic piston group is used, which has a new piston body of an improved design. The design improvements are:
... Keystone-type piston rings are now used. These piston rings have better resistance to deposits which can prevent free operation of the rings. Free operation of the rings will give a good seal for longer service life.
... The valve pockets machined into the top of the piston are now symmetrical (the same on both sides of the piston). With this design improvement, it is no longer necessary to have a mark on the piston for installation in a specific position. The new pistons can be installed either way in the cylinder. Formerly, it was necessary to install the pistons with the V-mark on the piston in alignment with the V-mark on the spacer plate.
... A relief (machined notch) is cut between the valve pocket and the outside diameter of the piston. This will prevent possible damage to the cylinder liner and the piston head land in some conditions of operation.
Adaptable As: Direct replacement.
