Main bearing: Notes

WARNING: This page is about a different car, the 2002 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

Set main bearings in their proper positions on cylinder block and main bearing cap.

Fig 1: Locating Upper Main Bearing With Oil Groove
Courtesy of NISSAN MOTOR CO., U.S.A.
Install main bearing cap and bearing beam to cylinder block.
Tighten all bolts in correct order.
Measure inner diameters "A" of each main bearing.

Fig 2: Measuring Inner Diameters Of Each Main Bearing
Courtesy of NISSAN MOTOR CO., U.S.A.
Measure outer diameters "Dm" of each crankshaft main journal.
Calculate main bearing clearance.
Main bearing clearance = A - Dm

Standard: 0.035 - 0.045 mm (0.0014 - 0.0018 in)

Limit: 0.065 mm (0.0026 in)
- If it exceeds the limit, replace bearing.
- If clearance cannot be adjusted using any standard bearing grade, grind crankshaft journal and use undersized bearing.
  
  Fig 3: Measuring Outer Diameters Of Each Crankshaft Main Journal
  Courtesy of NISSAN MOTOR CO., U.S.A.
1. When grinding crankshaft journal, confirm that "L" dimension in fillet roll is more than the specified limit.
  "L": 0.1 mm (0.004 in)
2. Refer to SERVICE DATA AND SPECIFICATION (SDS) for grinding crankshaft and available service parts.
  
  Fig 4: Measuring Bearing Clearance
  Courtesy of NISSAN MOTOR CO., U.S.A.
If crankshaft or cylinder block is replaced with a new one, select thickness of main bearings as follow:
1. Grade number of each cylinder block main journal is punched on the respective cylinder block. These numbers are punched in either Arabic or Alphabet. Refer to "CYLINDER BLOCK ".
  If measured diameter is out of grade punched, decide suitable grade using table in Service Data And Specifications .
  
  Fig 5: Identifying Cylinder Bore Bearing Housing Grade
  Courtesy of NISSAN MOTOR CO., U.S.A.
2. Grade number of each crankshaft main journal is punched on the respective crankshaft. These numbers are punched in either Arabic or Alphabet. Refer to "CRANKSHAFT ".
  If measured diameter is out of grade punched, decide suitable grade using table in Service Data And Specifications .
3. Select main bearing with suitable thickness according to the following table.
  Refer to "AVAILABLE MAIN BEARING " for available main bearings.
  
  Fig 6: Identifying Journal Diameter Pin Diameter Grade
  Courtesy of NISSAN MOTOR CO., U.S.A.