Crank Pin and Connecting Rod Bearings Inspection

WARNING: This page is about a different car, the 2004 Suzuki Vitara. However, it is still accessible from the selected car via links, so may be relevant.

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 then inspect rod bearing clearance as follow.
Crank Pin Diameter

Fig 1: Crank Pin & Connecting Rod Bearings Specifications Chart
Courtesy of SUZUKI OF AMERICA CORP.

Crank pin out-of-round (a - b)

Limit: 0.01 mm (0.0004 in.)

Crank pin taper (c - d)

Limit: 0.01 mm (0.0004 in.)

Fig 2: Measuring Crank Pin For Out-Of-Round Or Taper With Micrometer
Courtesy of SUZUKI OF AMERICA CORP.
Rod bearing:
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 General information
Serve 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 figure, undersize bearing thickness is 1.605 - 1.615 mm (0.0632 - 0.0635 in.) at the center of it.

Fig 3: Identifying Red Paint
Courtesy of SUZUKI OF AMERICA CORP.
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.
  
  Fig 4: Placing Piece Of Gauging Plastic To Full Width Of Crank Pin
  Courtesy of SUZUKI OF AMERICA CORP.
4. Install rod bearing cap to connecting rod.
  When installing cap, be sure to point arrow mark (1) on cap to crankshaft pulley side (2), as shown in Fig 5. After applying engine oil to rod bolts, tighten cap nuts to specified torque.
  
  NOTE: DO NOT turn crankshaft with gauging plastic installed.
  
  Tightening torque
  
  Connecting rod bearing cap nut (a): 45 N.m (4.5 kg-m, 32.5 lb-ft)
  
  Fig 5: Pointing Arrow Mark On Cap To Crankshaft Pulley Side
  Courtesy of SUZUKI OF AMERICA CORP.
5. Remove cap and using a scale (2) on gauging plastic envelope, measure gauging plastic width at the widest point (clearance).
  If clearance exceeds its limit, use a new standard size bearing and remeasure clearance.
  
  Connecting rod bearing clearance
  
  Standard: 0.045 - 0.063 mm (0.0018 - 0.0024 in.)
  
  Limit: 0.08 mm (0.0031 in.)
  
  Fig 6: Removing Cap & Using Scale On Gauging Plastic Envelope
  Courtesy of SUZUKI OF AMERICA CORP.
6. If clearance can not be brought to within its limit even by using a new standard size bearing, regrind crank pin to undersize as follows.
  1. Install 0.25 mm undersize bearing to connecting rod big end.
  2. Measure bore diameter of connecting rod big end.
  3. Regrind crank pin to the following finished diameter:
    Finished crank pin diameter = Measured big end bore diameter (including undersize bearing) - 0.054 mm (0.0021 in.)
  4. Confirm that bearing clearance is within above standard value.
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 No. 3.
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 53.0000 - 53.0060 mm (2.0867 - 2.0868 in.).
  
  Connecting rod big end inside diameter
  
  Fig 7: Connecting Rod Big End Inside Diameter Specifications Chart
  Courtesy of SUZUKI OF AMERICA CORP.
  
  Fig 8: Identifying Connecting Rod Big End Inside Diameter Number
  Courtesy of SUZUKI OF AMERICA CORP.
2. Next, check crankshaft pin diameter. On crank web No. 3, six 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 49.9940 - 50.0000 mm (1.9683 - 1.9685 in.).
  Crankshaft pin diameter
  
  Fig 9: Crankshaft Pin Diameter Specifications Chart
  Courtesy of SUZUKI OF AMERICA CORP.
  
  Fig 10: Identifying Crankshaft Pin Diameter
  Courtesy of SUZUKI OF AMERICA CORP.
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
  
  Fig 11: Standard Size Of Connecting Rod Bearing Thickness Specification Chart
  Courtesy of SUZUKI OF AMERICA CORP.
  
  Fig 12: Identifying Painted Mark
  Courtesy of SUZUKI OF AMERICA CORP.
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
  
  Fig 13: Standard Connecting Rod Bearing Size Specification Chart
  Courtesy of SUZUKI OF AMERICA CORP.
5. Check bearing clearance with newly selected standard bearing referring to "Selection of Connecting Rod Bearing" under Crank Pin and Connecting Rod Bearings Inspection .
  If clearance still exceeds its limit, use next thicker bearing and recheck clearance.