1D
Crank Pin and Connecting Rod Bearings Inspection
Reference: Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and Assembly:M13A
Crank Pin Diameter
Inspect crank pin for uneven wear or damage. Measure crank pin for out-of-round or taper with a micrometer. If crank pin is damaged or out-of round or taper is out of limit, replace crankshaft or regrind crank pin to undersize and use undersize bearing.
Crank pin diameter
Connecting rod bearing size Crank pin diameter
Standard 41.982 – 42.000 mm
(1.6528 – 1.6535 in.)
0.25 mm (0.0098 in.) undersize 41.732 – 41.750 mm
(1.6430 – 1.6437 in.)
Out-of-round
A – B
Taper
a – b
Crank pin taper and out-of-round
Limit: 0.01 mm (0.0004 in.)
Connecting Rod Bearing General Information
Service connecting rod bearings are available in standard size and 0.25 mm (0.0098 in.) undersize, and standard size bearing has 5 kinds of bearings differing in tolerance.
For identification of undersize bearing, it is painted red at the position as indicated in the figure, undersize bearing thickness is 1.605 – 1.615 mm (0.0632 – 0.0635 in.) at the center of it.
1. Painting
Connecting Rod Bearing Visual Inspection
Inspect bearing shells for signs of fusion, pitting, burn or flaking and observe contact pattern. Bearing shells found in defective condition must be replaced.
Connecting Rod Bearing Clearance
1) Before checking bearing clearance, clean bearing and crank pin.
2) Install bearing in connecting rod and bearing cap.
3) Place a piece of gauging plastic (1) to full width of crank pin as contacted by bearing (parallel to crankshaft), avoiding oil hole.
4) Install rod bearing cap (1) to connecting rod.
When installing cap, be sure to point arrow mark (2) on cap to crankshaft pulley side, as shown in the figure. After applying engine oil to rod bolts, tighten cap nuts (3) gradually as follows.
a) Tighten all cap nuts to 15 N·m (1.5 kgf-m, 11.0 lbf-ft)
b) Retighten them to 45°
c) Repeat Step b) once again.
Tightening torque
Connecting rod bearing cap nut ( a ): 15 N·m (1.5 kgf-m, 11.0 lbf-ft) and extra tightening 45° twice
5) Remove cap and using a scale (1) on gauging plastic envelope (2), measure gauging plastic (2) width at the widest point (clearance).
If clearance exceed its limit, use a new standard size bearing and remeasure clearance.
Connecting rod bearing clearance
Standard: 0.029 – 0.047 mm (0.0011 – 0.0019 in.)
Limit: 0.065 mm (0.0026 in.)
6) If clearance can not be brought to within its limit even by using a new standard size bearing, regrind crank pin to undersize and use 0.25 mm undersize bearing.
NOTE:
After checking the rod bearing clearance, make sure that checking for “Connecting rod bolt deformation” in Piston Pins and Connecting Rods Inspection:M13A .
Selection of Connecting Rod Bearings
NOTE:
• If bearing is in malcondition, or bearing clearance is out of specification, select a new standard bearing according to the following procedure and install it.
• When replacing crankshaft or connecting rod and its bearing due to any reason, select new standard bearings to be installed by referring to numbers stamped on connecting rod and its cap and/or alphabets stamped on crank web of No.3 cylinder.
1) Check stamped numbers on connecting rod and its cap as shown.
Three kinds of numbers (“1”, “2” and “3”) represent the following connecting rod big end inside diameters.
For example, stamped number “1” indicates that corresponding connecting rod big end inside diameter is 45.000 – 45.006 mm (1.7717 – 1.7718 in.).
Connecting rod big end inside diameter
Stamped numbers connecting rod big end inside diameter
1 45.0000 – 45.0060 mm (1.7717 – 1.7718 in.)
2 45.0061 – 45.0120 mm (1.7719 – 1.7721 in.)
3 45.0121 – 45.0180 mm (1.7722 – 1.7723 in.)
[A]: Weight indication mark
[B]: Connecting rod big end inside diameter number
2) Next, check crankshaft pin diameter. On crank web No.3, four alphabets are stamped as shown in figure. Three kinds of alphabet (“A”, “B” and “C”) represent the following crankshaft pin diameter respectively.For example, stamped “A” indicates that corresponding crankshaft pin diameter is 41.994 – 42.000 mm (1.6533 – 1.6534 in.).
Crankshaft pin outer diameter
Stamped alphabet Crankshaft pin diameter
A 41.9940 – 42.0000 mm (1.6533 – 1.6534 in.)
B 41.9880 – 41.9939 mm (1.6531 – 1.6532 in.)
C 41.9820 – 41.9879 mm (1.6529 – 1.6530 in.)
[A]: Crankshaft pin diameter for No.1 cylinder
[B]: Crankshaft pin diameter for No.2 cylinder
[C]: Crankshaft pin diameter for No.3 cylinder
[D]: Crankshaft pin diameter for No.4 cylinder
3) There are five kinds of standard bearings differing in thickness. To distinguish them, they are painted in the following colors at the position as indicated in figure.
Each color indicated the following thickness at the center of bearing.
Standard size of connecting rod bearing thickness
Color painted Bearing thickness
Blue 1.4991 – 1.5020 mm (0.05902 – 0.05913 in.)
Yellow 1.4961 – 1.4990 mm (0.05890 – 0.05901 in.)
Nothing 1.4931 – 1.4960 mm (0.05878 – 0.05889 in.)
Black 1.4901 – 1.4930 mm (0.05867 – 0.05877 in.)
Green 1.4870 – 1.4900 mm (0.05855 – 0.05866 in.)
1. Paint
4) From number stamped on connecting rod and its cap and alphabets stamped on crank web No.3, determine new standard bearing to be installed to connecting rod big end inside, by referring to table.For example, if number stamped on connecting rod and its cap is “1” and alphabet stamped on crank web No.3 is “B”, install a new standard bearing painted in “Black” to its connecting rod big end inside.
Specification of new standard connecting rod bearing size
      Number stamped on connecting rod and its cap (connecting rod big end inside diameter)
      1 2 3
Alphabet stamped on crank web No.3 (Crankshaft pin diameter)
 		 A Green Black Nothing
B Black Nothing Yellow
C Nothing Yellow Blue
      New standard bearing to be installed.
5) Using scale (1) on gaging plastic (2), check bearing clearance with newly selected standard bearing.
If clearance still exceeds its limit, use next thicker bearing and recheck clearance.