TM 10-3950-672-24-2
Some housings are machined for the use of an optional
engine barring device.
Piston and Rod Assemblies
Piston features include: high swirl combustion bowl cast
aluminum body and three ring grooves. Always check
the part number to be sure that the correct configuration
is used during piston replacement.
The piston ring sets are also different. While both sets
consist of three rings, the top ring of the
turbocharged/aftercooled set has a keystone profile
which operates in a ni-resist insert cast into the piston.
The naturally aspirated top ring is square cut and
operates in a groove machined into the aluminum
piston.
A free floating, hollow piston pin is used to attach the
piston to the connecting rod. Lubrication of the pin and
journal is accomplished by residual spray from piston
cooling.
5-165