Connecting Rod Clearance Inspection

• If it exceeds the maximum specification, replace the connecting rod or crankshaft.

Standard side clearance at the large end of connecting rod 0.14-0.36 mm {0.006-0.014 in} 

Maximum side clearance at the large end of connecting rod 0.465 mm {0.0183 in} 

Fig 1: Checking Connecting Rod Clearance

Courtesy of MAZDA MOTORS CORP.

1. Cut the plastigauge as wide as the connecting rod bearing width, place it parallel to the crankshaft, avoiding the oil hole.
2. Install the lower connecting rod bearing and connecting rod cap. (See CYLINDER BLOCK ASSEMBLY (I) .)
3. Remove the connecting rod cap. (See CYLINDER BLOCK DISASSEMBLY (II) .)
4. Measure the oil clearance at the large end of the connecting rod.
   • If it exceeds the maximum specification, replace the bearing or grind the crank pin and use oversize bearings so that the specified clearance is obtained.
     Fig 2: Identifying Connecting Rod Bearing Plastigauge

     Courtesy of MAZDA MOTORS CORP.

   Standard bearing oil clearance at the large end of the connecting rod 0.026-0.052 mm {0.0011-0.0020 in} 

   Maximum bearing oil clearance at the large end of the connecting rod 0.10 mm {0.0039 in} 

   Connecting rod bearing size 

   STD: 1.502-1.519 mm {0.05914-0.05980 in} 

   OS 0.25: 1.628-1.631 mm {0.06410-0.06421 in} 

   OS 0.50: 1.753-1.756 mm {0.06902-0.06913 in}