GEAR-SUN 1183183 - Caterpillar

The piston height above the top face of the cylinder block is controlled by the length of the connecting rod. Six grades of length of connecting rods may be supplied in the engine. Four grades of length of connecting rods and one piston are available in service in order to obtain the correct piston height above the top face of the cylinder block. The different grades of length are manufactured by machining the hole in the piston pin bearing in an off-center position. Note: If the connecting rod is replaced, ensure that the same grade of length as the original connecting rod is used. However, if the crankshaft or the cylinder block is replaced, the required grade of length of the connecting rods may change.The color code is marked on the side of the connecting rod or on the connecting rod cap in order to identify the length grade for the connecting rod. The difference between each grade of length is 0.046 mm (0.0018 inch).Connecting rods are color coded. The color code is a reference for the length (Y) of the connecting rod. Refer to Table 2 for the different lengths of connecting rods.
Illustration 1 g00915056
Table 1
Length Grades for Connecting Rods    
Grade Letter    Color Code    Length (Y)    
F     Red    
165.728 to 165.761 mm (6.5247 to 6.5260 inch)    
G     Orange    
165.682 to 165.715 mm (6.5229 to 6.5242 inch)    
H     White    
165.637 to 165.670 mm (6.5211 to 6.5224 inch)    
J     Green    
165.591 to 165.624 mm (6.5193 to 6.5206 inch)    
K     Purple    
165.545 to 165.578 mm (6.5175 to 6.5188 inch)    
L     Blue    
165.499 to 165.532 mm (6.5157 to 6.4961 inch)    Serrated Connecting Rods and Flat Connecting Rods
Illustration 2 g00636808
(1) Inside diameter of connecting rod for the piston pin bearing ... 43.01 to 43.04 mm (1.693 to 1.694 inch) (2) Outside diameter of piston pin bearing ... 43.11 to 43.15 mm (1.6972 to 1.6988 inch)Inside diameter of piston pin bearing after reaming ... 39.723 to 39.738 mm (1.5638 to 1.5645 inch)Clearance between piston pin bearing and piston pin ... 0.023 to 0.044 mm (0.0009 to 0.0017 inch) (3) Distance between center of piston pin and center of connecting rod bearing bore ... 219.05 to 219.10 mm (8.624 to 8.626 inch) (4) Connecting rod bearings are available for remachined journals of the crankshaft which have the following undersize dimensions:0.25 mm (0.010 inch)0.51 mm (0.020 inch)0.76 mm (0.030 inch)Shell thickness Naturally aspirated engines ... 1.835 to 1.842 mm (0.0723 to 0.0725 inch) Turbocharged engines ... 1.835 to 1.844 mm (0.0723 to 0.0726 inch)Width of connecting rod bearing Naturally aspirated engines ... 31.62 to 31.88 mm (1.245 to 1.255 inch) Turbocharged engines ... 31.55 to 31.88 mm (1.240 to 1.255 inch)Bearing clearance Naturally aspirated engines ... 0.035 to 0.081 mm (0.0014 to 0.0032 inch) Turbocharged engines ... 0.030 to 0.081 mm (0.0012 to 0.0032 inch) (5) Inside diameter of connecting rod for connecting rod bearing