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Home >> Nissan-Datsun >> 2003 >> Sentra SE-R Spec V >> Repair and Diagnosis >> Engine Mechanical >> Engine Mechanical - Qr25DE >> Cylinder Block >> Disassembly and Assembly >> Disassembly

Disassembly and Assembly: Disassembly

  1. Remove the engine and transaxle as an assembly from the vehicle, and separate the transaxle from the engine. Refer to REMOVAL AND INSTALLATION .
  2. Mount the engine on a suitable engine stand.
  3. Drain any remaining engine oil and coolant from the engine.
  4. Remove the following components and associated parts.
    5. CAUTION: Carefully handle the sensor and do not drop the sensor.
  5. Remove the knock sensor.
    6. CAUTION:
    • Avoid impacts such as a dropping.
    • Do not disassemble.
    • Keep it away from metal particles.
    • Do not place sensor close to magnetic materials.
    Fig 1: Removing Crankshaft Position Sensor (POS)
    G02007907Courtesy of NISSAN MOTOR CO., U.S.A.
  6. Remove Crankshaft Position sensor (POS).
    7. CAUTION:
    • Be careful not to damage the flywheel contact surface for the clutch disc.
    Fig 2: Removing Mounting Bolts
    G02007908Courtesy of NISSAN MOTOR CO., U.S.A.
    NOTE:
    • The flywheel two-block construction allows movement in response to transmission side pressure, or when twisted in its rotational direction, therefore, some amount of noise is normal.
  7. Remove the flywheel (M/T models) or drive plate (A/T models). Hold the crankshaft with a stopper plate and remove the mounting bolts.
  8. Remove pilot converter using Tool (A/T models).
    Fig 3: Removing Pilot Converter Using Tool
    G02007909Courtesy of NISSAN MOTOR CO., U.S.A.
  9. Remove the piston and connecting rod assemblies.
    Fig 4: Removing Piston & Connecting Rod Assemblies
    G02007910Courtesy of NISSAN MOTOR CO., U.S.A.
    1. Position the crankshaft and corresponding connecting rod, to be removed, to the bottom dead center stroke.
    2. Remove the connecting rod cap. Number the cap so it can be assembled in the same position.
    3. Using a hammer handle or similar tool, push the piston and connecting rod assembly out of the top of the cylinder block. Number the piston and rod so it can be assembled in the same position.
  10. Remove the connecting rod bearings. If reusing, number them so they can be assembled in the same position and direction.
    CAUTION:
    • When removing them, note the installation position. Keep them in the correct order.
    11. CAUTION:
    • When removing the piston rings, be careful not to damage the piston.
    • Be careful not to damage piston rings by expanding them excessively, if reusing them.
    • Before removing the piston rings, check the piston ring side clearance. Refer to PISTON RING SIDE CLEARANCE .
    Fig 5: Removing Piston Ring
    G02007911Courtesy of NISSAN MOTOR CO., U.S.A.
  11. Remove the piston rings from the piston.
    • Use a piston ring expander.
  12. Remove the piston from the connecting rod as follows.
    1. Using a snap ring pliers, remove the two snap rings.
      Fig 6: Removing Snap Ring
      G02007912Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Heat the piston to 60-70°C (140-158°F) with a heat gun, or equivalent.
      Fig 7: Heating Piston
      G02007913Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Push out piston pin with a punch of an outer diameter of approximately 19 mm (0.75 in).
      Fig 8: Pushing Out Piston Pin
      G02007914Courtesy of NISSAN MOTOR CO., U.S.A.
  13. Remove the lower cylinder block mounting bolts.
    • Before loosening the lower cylinder block mounting bolts, measure the crankshaft side clearance. Refer to CRANKSHAFT SIDE CLEARANCE .
    • Loosen them in the order shown in Fig 9 to remove them.
      Fig 9: Identifying Lower Cylinder Block Bolts Loosening Sequence
      G02007915Courtesy of NISSAN MOTOR CO., U.S.A.
  14. Remove the lower cylinder block.
    • Using Tool (seal cutter) cut the RTV Silicone Sealant and remove the lower cylinder block from the cylinder block.
      CAUTION: Be careful not to damage the mounting surface.
  15. Remove the crankshaft.
    CAUTION:
    • Do not damage or deform the signal plate while mounted on the crankshaft.
    • When setting the crankshaft on a flat surface, use a block of wood to avoid interference between the signal plate and the surface.
    • Do not remove signal plate unless it is necessary.
    Fig 10: Identifying Crankshaft & Signal Plate
    G02007916Courtesy of NISSAN MOTOR CO., U.S.A.
  16. Pull the rear oil seal out of the rear end of the crankshaft.
    CAUTION: Do not to damage the crankshaft or cylinder block when removing the rear oil seal.
    NOTE: When replacing the rear oil seal without removing the cylinder block, use a screwdriver to pull it out from between crankshaft and block.
  17. Remove the main bearings and thrust bearings from the cylinder block and lower cylinder block.
    CAUTION: Identify and number the bearings, if reusing them, so that they are assembled in the same position and direction.
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