Figure 3-22. Oil pump, disassembly and reassembly.
3-23. Connecting Rods and Pistons
(3) Remove the piston and connecting rod as
shown in figure 3-24A.
a. General. The connecting rods and caps are
c. Disassembly. Refer to figure 3-25 and
drop forged. The pistons are made of aluminum
disassemble piston and connecting rod in numerical
alloy and have three rings fitted on each piston. The
top ring is a compression ring. The center ring is the
scraper ring and the bottom ring is an oil ring.
(1) Use an inside micrometer to measure the
cylinder bores for wear. If the cylinder bores are
( 1 ) Remove the oil pump (para 3-22).
worn in excess of 3.2485 inches rebore to fit the
(2) Refer to figure 3-23 and remove the
next size of available oversize pistons.
(2) Place ring in cylinder bore in approximate
operating position and measure gap with a feeler
Replace rod caps immediately so they are on
gage. Refer to table 1-1 for proper piston ring gap.
the correct rod for reassembly. Rods and caps
If ring gap is too large, replace piston ring. If ring
are numbered on one side. These numbers
gap is too small, clamp a file in a vise and position
must be on the same side for reassembly. Rod
assemblies should be marked or tagged for
the ring on file with the file in ring gap. Lightly
reassembly into same cylinder.
squeeze ring together and move ring back and forth