Nissan Micra K11 silhouetteK11

CYLINDER BLOCK — Inspection (Cont'd); Crankshaft; Bearing Clearance (Supplement-V)

EM-5038prose procedure

Piston diameter 'A' is given as a single value (76.939 mm). Piston-to-bore clearance 'B' is the resulting range (0.07-0.10 mm). NEM297 explicitly numbers main bearing No.1 at the flywheel side — same convention as the main-bearing-cap loosening order on EM-5036.

Continued from EM-5037

Inspection (Cont'd)

Piston-to-bore clearance (continued)

  1. 3
    Measure piston skirt diameter.
    Piston diameter "A": 76.939 mm (3.0291 in)
    Micrometer measuring the piston skirt diameter at location 'A' (perpendicular to the piston pin axis) — illustrates Inspection step 3 (measure piston diameter 'A').
    NEM319
  2. 4
    Check piston-to-bore clearance. If out of specification, replace piston and/or cylinder block.
    Piston-to-bore clearance "B": 0.07 - 0.10 mm (0.003 - 0.004 in)

CRANKSHAFT

Crankshaft inspection

  1. 1
    Check crankshaft main and pin journals for score, wear or cracks.
  2. 2
    With a micrometer, measure journals for taper and out-of-round.
    Out-of-round (X − Y): Less than 0.005 mm (0.0002 in)
    Taper (A − B): Less than 0.005 mm (0.0002 in)
    Crankshaft journal measurement schematic: side view labelling planes A and B along the journal axis (for taper A-B), with cross-section view labelling axes X and Y across the journal (for out-of-round X-Y). Caption: 'Taper: A - B Out-of-round: X - Y'.
    SEM316A
  3. 3
    Measure crankshaft runout.
    Runout (Total indicator reading): Less than 0.05 mm (0.0020 in)
    Crankshaft supported on V-blocks with a dial indicator riding on the centre main journal — illustrates Crankshaft step 3 (measure crankshaft runout / total indicator reading).
    SEM346D

BEARING CLEARANCE

Main bearing

Main bearing clearance

  1. 1
    Set main bearings in their proper positions on cylinder block and main bearing cap.
    Thrust bearing is fitted upper only.
    Upper bearings have an oil groove; lower bearings do not.
    No.1 bearing is at the flywheel side.
    Exploded view of main bearing positions in the cylinder block: upper-bank shows the thrust bearing (upper only), upper bearings with oil grooves, with 'No.1 bearing (flywheel side)' callout and a 'Front' arrow. Lower-bank shows the lower bearings without oil grooves seated in the main bearing caps. Used for Bearing Clearance / Main bearing step 1.
    NEM297
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