ARMY TM 9-6115-670-14&P
6-54
6.23. CONNECTING ROD.
This task covers: a. Test
b. Repair
c. Replace
INITIAL SETUP
Tools
General Mechanic's Tool Kit
(Item 1, Appendix B)
Inside Micrometer Caliper
(Item 42, Appendix B)
Outside Micrometer Caliper
(Item 43, Appendix B)
Connecting Rod Alignment Tool
(Item 14, Appendix B)
Connecting Rod Small End Bushing Tool
(Item 17, Appendix B)
Equipment Conditions
Piston removed from cylinder (para 6.22.).
Materials/Parts
Connecting Rod
Small End Bushing
Piston Pin
Crankpin Bearing
TEST
a. Remove connecting rod from piston (perform steps a and b of REPLACE).
b. Test oil clearance between piston pin and small end bushing.
(1)
Use outside micrometer caliper to measure the OD of the piston pin where it contacts the
bushing. OD should be between 0.78748 and 0.78783 in. (20.002 and 20.011 mm) (Sheet
1).
(2)
Use inside micrometer caliper to measure the ID of the small end bushing. ID should be
between 0.78839 and 0.78897 in. (20.025 and 20.040 mm) (Sheet 1).
(3)
Calculate the oil clearance.
(4)
If oil clearance exceeds 0.0039 in. (0.10 mm), repair connecting rod by replacing small
end bushing.
(5)
Recalculate the oil clearance. If it still exceeds 0.0039 in. (0.10 mm), replace the piston
pin.
