3-40. PISTONS, CONNECTING RODS AND LINERS.
Connecting Rod Bearings
3-40.1. PISTON - MAINTENANCE INSTRUCTIONS.
a. The trunk-type malleable iron piston is plated with a protective coating of tin which permits close fitting,
reduces scuffing and prolongs piston life. The top of the piston forms the combustion chamber bowl and is
designed to compress the air into the close proximity to the fuel spray.
b. Each piston is internally braced with fin-shaped ribs and circular struts, scientifically designed to draw
heat rapidly from the piston crown and transfer it to the lubricating oil spray to ensure better control of piston
c. The piston is cooled by a spray of lubricating oil directed at the underside of the piston head from a
nozzle in the top of the connecting rod, by fresh air from the blower to the top of the piston and indirectly by the
water jacket around the cylinder.
d. Each piston is balanced to close limits by machining a balancing rib, provided on the inside at the
bottom of the piston skirt.