Piston-To-Bore Clearance

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.

Using a bore gauge, measure cylinder bore for wear, out-of-round and taper.
Cylinder bore inner diameter

Fig 1: Cylinder Bore Diameter Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 2: Measuring Piston-To-Bore Clearance
Courtesy of NISSAN MOTOR CO., U.S.A.

If it exceeds the limit, rebore all cylinders. Replace cylinder block if necessary.

Out-of-round (X - Y):

Limit 0.015 mm (0.0006 in)

Taper (A - B - C):

Limit 0.015 mm (0.0006 in)
Check for scratches and seizure. If seizure is found, hone it.

Fig 3: Identifying Bore Limit
Courtesy of NISSAN MOTOR CO., U.S.A.
- If both cylinder block and piston are replaced with new ones, select piston of the same grade number punched on cylinder block rear position. These numbers are punched in either Arabic or Roman numerals.
  
  Fig 4: Locating Cylinder Bore And Bearing Housing Grade
  Courtesy of NISSAN MOTOR CO., U.S.A.
Measure piston skirt diameter.
Piston diameter "A": Refer to ( " PISTON, PISTON RING AND PISTON PIN ").

Measuring point "a" (Distance from the top): 41.0 mm (1.61 in)
Check that piston-to-bore clearance is within specification.
Piston-to-bore clearance "B": 0.010 - 0.030 mm (0.0004 - 0.0012 in)
Determine piston oversize according to amount of cylinder wear.
Oversize pistons are available for service.

Refer to ( " PISTON, PISTON RING AND PISTON PIN ").

Fig 5: Measuring Piston Skirt Diameter
Courtesy of NISSAN MOTOR CO., U.S.A.
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

C: Honing allowance 0.02 mm (0.0008 in)
Install main bearing caps, and tighten to the specified torque. Otherwise, cylinder bores may be distorted in final assembly.
Cut cylinder bores.
- When any cylinder needs boring, all other cylinders must also be bored.
- Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 in) or so in diameter at a time.
Hone cylinders to obtain specified piston-to-bore clearance.
Measure finished cylinder bore for out-of-round and taper.
- Measurement should be done after cylinder bore cools down.