Main Bearing Oil Clearance

Method by Calculation 

• Install main bearings (3) to cylinder block (1) and ladder assembly (2) and tighten ladder assembly bolts. Refer to CYLINDER BLOCK : Disassembly & Assembly .

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• Measure the inner diameter (A) of main bearing with bore gauge.
• (Bearing oil clearance) = (Main bearing inner diameter) - (Crankshaft main journal diameter)

• If measured value exceeds limit select proper main bearing. Use main bearing inner diameter and crankshaft main journal diameter to obtain specified bearing oil clearance. Refer to CYLINDER BLOCK : Disassembly & Assembly .

Method by Using Plastigage 

• Remove engine oil and dust on crankshaft main journal and surfaces of each bearing completely.
• Cut plastigage slightly shorter than bearing width and place it in crankshaft axial direction avoiding oil holes.
• Install main bearings on cylinder block and ladder assembly and tighten ladder assembly bolts. Refer to CYLINDER BLOCK : Disassembly & Assembly .
  CAUTION: Do not rotate crankshaft.
• Remove ladder assembly and bearings and using the scale (A) on the plastigage bag measure the plastigage width.

  Courtesy of NISSAN NORTH AMERICA, INC.

  NOTE: The procedure when measured value exceeds the limit is same as that described in "Method by Calculation".