Piston To Cylinder Bore Clearance

Cylinder Bore Diameter

• Measure the cylinder bore for wear, out-of-round and taper at six different points on each cylinder [(X) and (Y) directions at (A), (B) and (C)].
  NOTE: When determining cylinder bore grade, measure cylinder bore at (B) position.
  Fig 1: Identifying Cylinder Bore Diameter Measuring Points Location In X And Y Direction

  Courtesy of NISSAN NORTH AMERICA, INC.

  Standard diameter: 98.000 - 98.030 mm (3.8583 - 3.8594 in) 

  Wear limit: 0.20 mm (0.0079 in) 

  Out-of-round (Difference between "X" and "Y"): 

  Limit: 0.015 mm (0.0006 in) 

  Taper limit (Difference between "A" and "C"): 

  Limit: 0.010 mm (0.0004 in) 

  Fig 2: Measuring Cylinder Bore Dimension Using Bore Gauge

  Courtesy of NISSAN NORTH AMERICA, INC.
• If measured value exceeds the repair limit, or if there are scratches and/or seizure on the cylinder inner wall, hone or bore the inner wall.

Piston Skirt Diameter

• Measure piston skirt diameter using suitable tool.

  Standard: 97.980 - 98.010 mm (3.8575 - 3.8587 in) 

  Fig 3: Measuring Piston Skirt Diameter Using Micrometer

  Courtesy of NISSAN NORTH AMERICA, INC.
• Measure point "H".

Distance from the top: 39 mm (1.54 in) 

Fig 4: Identifying Piston Height

Courtesy of NISSAN NORTH AMERICA, INC.

Piston to Cylinder Bore Clearance

• Calculate by using diameter of the piston skirt and the cylinder bore diameter (direction X, position B). (Clearance) = (Cylinder bore diameter) - (piston skirt diameter)

  Standard: 0.010 - 0.030 mm (0.0004 - 0.0012 in) 

  Limit: 0.08 mm (0.0031 in) 

• If calculation exceeds the limit, replace piston/piston pin assembly.

Reboring Cylinder Bore

1. Cylinder bore size is determined by adding piston-to-bore clearance to piston diameter (A).

   Rebored size calculation: D = A + B - C where, 

   D: Bored diameter 

   A: Piston diameter as measured 

   B: Piston - to - bore clearance (standard value) 

   C: Honing allowance 0.02 mm (0.0008 in) 

2. Install main bearing caps, and tighten them to the specified torque. Otherwise, cylinder bores may be distorted in final assembly.
3. Cut the cylinder bores.
   NOTE:

   • When any cylinder needs boring, all other cylinders must also be bored.
   • Do not cut too much out of cylinder bore at one time. Cut only 0.05 mm (0.0020 in) or so in diameter at a time.
4. Hone cylinders to obtain the specified piston-to-bore clearance.
5. Measure finished cylinder bore for out-of-round and taper.