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Home >> Infiniti >> 2015 >> QX60 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (Engine Mechanical (Except Hybrid)) >> Removal And Installation >> Cylinder Head >> Inspection After Disassembly >> Valve Seat Replacement

Valve Seat Replacement

WARNING: This page is about a different car, the 2016 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.
  1. Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in cylinder head. Set the machine depth stop to ensure this.
    G04073072Courtesy of NISSAN NORTH AMERICA, INC.
  2. Ream cylinder head recess for service valve seat.
    Oversize : 0.5 mm (0.020 in)
    Intake : 38.500 - 38.516 mm (1.5157 - 1.5164 in)
    Exhaust : 32.100 - 32.116 mm (1.2638 - 1.2644 in)

    Be sure to ream in circles concentric to the valve guide center. 

    This will enable valve seat to fit correctly. 

  3. Heat cylinder head to 110 - 130°C (230 - 266°F) by soaking in heated oil.
  4. Press fit valve seat until it seats on the bottom.
  5. Cut or grind valve seat using suitable tool to the specified dimensions. Refer to CYLINDER HEAD .
  6. After cutting, lap valve seat with abrasive compound.
  7. Check valve seating condition.
    Seat face angle (α) : 45° 15' - 45° 45' degrees/minutes
    Contacting width (W) for intake : 1.18 - 1.22 mm (0.0465 - 0.0480 in)
    Contacting width (W) for exhaust : 1.38 - 1.42 mm (0.0543 - 0.0559 in)
    G04159865Courtesy of NISSAN NORTH AMERICA, INC.
  8. Use a depth gauge to measure the distance between the mounting surface of the cylinder head spring seat and the valve stem end. If the distance is shorter than specified, repeat step 5 to adjust it. If it is longer, replace the valve seat with a new one.
    G04159866Courtesy of NISSAN NORTH AMERICA, INC.
    Valve seat resurface limit (L) intake : 41.16 - 41.76 mm (1.6205 - 1.6441 in)
    Valve seat resurface limit (L) exhaust : 41.09 - 41.69 mm (1.6177 - 1.6413 in)
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