Infinity_QX4_1998-2003

Cylinder Head

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Removal & Installation



3.3L Engine
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Relieve the fuel system pressure.
  6.  
  7. Remove the or disconnect the following:
    NOTE
    The cylinder head bolts vary in length. Note the bolt locations for assembly.



    Negative battery cable
     
    Accessory drive belts
     
    Front cover
     
    Timing belt. Refer to the Timing Belt unit repair section.
     
    Upper intake manifold
     
    Lower intake manifold
     
    Camshaft sprockets
     
    Rear timing cover
     
    Distributor
     
    Exhaust front pipes
     
    A/C compressor
     
    Alternator
     
    Power steering pump
     
    Accessory brackets
     
    Valve covers. Loosen the bolts in several passes and in sequence.

    Click image to see an enlarged view

    Fig. Valve cover bolt loosening sequence-3.3L engine



    Click image to see an enlarged view

    Fig. Cylinder head loosening sequence-3.3L engine



    Click image to see an enlarged view

    Fig. Exploded view of the cylinder head assembly-3.3L engine

     
    Cylinder heads with the exhaust manifolds attached. Loosen the bolts in several passes and in sequence.
     

  8.  

To install:

Click image to see an enlarged view

Fig. Cylinder head torque sequence-3.3L engine

  1. Install the cylinder heads and the lower intake manifold at the same time. Tighten the bolts in sequence as follows:
    1. Step 1: Tighten the cylinder head bolts to 22 ft. lbs. (29 Nm)
    2.  
    3. Step 2: Tighten the cylinder head bolts to 43 ft. lbs. (59 Nm)
    4.  
    5. Step 3: Loosen all cylinder head bolts completely
    6.  
    7. Step 4: Tighten the cylinder head bolts to 84 inch lbs. (10 Nm)
    8.  
    9. Step 5: Tighten the intake manifold fasteners to 35 inch lbs. (4 Nm)
    10.  
    11. Step 6: Tighten the intake manifold fasteners to 13 ft. lbs. (18 Nm)
    12.  
    13. Step 7: Tighten the intake manifold fasteners to 12 - 14 ft. lbs. (16 - 20 Nm)
    14.  
    15. Step 8: Loosen all intake fasteners completely
    16.  
    17. Step 9: Tighten the cylinder head bolts to 22 ft. lbs. (29 Nm)
    18.  
    19. Step 10: Tighten the cylinder head bolts 60 - 65 degrees OR tighten to 40 - 47 ft. lbs. (54 - 64 Nm)
    20.  
    21. Step 11: Tighten the cylinder head sub-bolts to 80 - 105 inch lbs. (9 - 12 Nm)
    22.  
    23. Step 12: Tighten the intake manifold fasteners to 35 inch lbs. (4 Nm)
    24.  
    25. Step 13: Tighten the intake manifold fasteners to 78 inch lbs. (9 Nm)
    26.  
    27. Step 14: Tighten the intake manifold fasteners to 70 - 84 inch lbs. (6 - 7 Nm)
    28.  

  2.  
  3. Install or connect the following:

    Valve covers
     
    Accessory brackets
     
    Power steering pump
     
    Alternator
     
    A/C compressor
     
    Exhaust front pipes
     
    Distributor
     
    Rear timing cover
     
    Camshaft sprockets
     
    Upper intake manifold
     
    Timing belt
     
    Front cover
     
    Accessory drive belts
     
    Negative battery cable
     

  4.  
  5. Fill the cooling system.
  6.  
  7. Start the engine and check for leaks.
  8.  

3.5L Engine
  1. Remove the engine from vehicle.
  2.  
  3. Remove the exhaust manifolds in reverse order of installation.
  4.  
  5. Place engine on a work stand.
  6.  
  7. Remove the aluminum oil pan
  8.  
  9. Remove the timing chain.
  10.  
  11. Remove the intake manifold in reverse order of installation.
  12.  
  13. Remove the water outlet.
  14.  
  15. Remove the rear timing chain case bolts. Loosen in numerical order as shown in the figure.

    Click image to see an enlarged view

    Fig. Rear timing case loosening sequence-3.5L engine

  16.  
  17. Remove the rear timing chain case.
  18.  
  19. Remove the O-rings to cylinder head.
  20.  
  21. Remove the O-rings to cylinder block.
  22.  
  23. Remove the intake valve timing control solenoid valves.
  24.  
  25. Remove the intake and exhaust camshafts and camshaft brackets. Equally loosen camshaft bracket bolts in several steps in the numerical order shown in the figure. For reinstallation, be sure to put marks on camshaft bracket before removal.

    Click image to see an enlarged view

    Fig. Right camshaft loosening sequence-3.5L engine



    Click image to see an enlarged view

    Fig. Left camshaft loosening sequence-3.5L engine

  26.  
  27. Remove the RH and LH camshaft chain tensioners from cylinder head.
  28.  
  29. Remove the cylinder head bolts. Cylinder head bolts should be loosened in two or three steps.
  30.  
  31. Remove the cylinder head.
  32.  

To install:

  1. Before installing rear timing chain case, remove old liquid gasket from mating surface using a scraper. Also remove old liquid gasket from mating surface of cylinder block. Remove old liquid gasket from the bolt hole and thread.
  2.  
  3. Before installing cam bracket, remove old liquid gasket from mating surface using a scraper.
  4.  
  5. Before installing the cylinder head gasket, be sure that No. 1 cylinder is at TDC. At this time, the crankshaft key should face toward the right bank.
  6.  
  7. Install cylinder heads with new gaskets.
    NOTE
    Do not rotate crankshaft and camshaft separately, or valves will strike piston heads.


    CAUTION
    Cylinder head bolts are tightened by plastic zone tightening method. Whenever the size difference between d1 and d2 exceeds the limit, replace them with new ones. Limit (d1 - d2): 0.0043 in. Lubricate threads and seat surfaces of the bolts with new engine oil.



    Click image to see an enlarged view

    Fig. Head bolt checking-3.5L engine



    Click image to see an enlarged view

    Fig. Right cylinder head bolt torque sequence-3.5L and 4.0L engines



    Click image to see an enlarged view

    Fig. Left cylinder head bolt torque sequence-3.5L and 4.0L engines

  8.  
  9. Install cylinder head outside bolts Tighten in numerical order shown in the figure. Tightening procedure:
    1. Tighten all bolts to 98 Nm (10 kg-m, 72 ft-lb).
    2.  
    3. Completely loosen all bolts.
    4.  
    5. Tighten all bolts to 34 to 44 Nm (3.5 to 4.5 kg-m, 25 to 33 ft-lb).
    6.  
    7. Turn all bolts 90 to 95 degrees clockwise.
    8.  
    9. Turn all bolts 90 to 95 degrees clockwise.
    10.  

  10.  
  11. Install camshaft chain tensioners on both sides of cylinder head.
  12.  
  13. Install exhaust and intake camshafts and camshaft brackets.
    NOTE
    Intake camshaft has a drill mark on camshaft sprocket mounting flange. Install it on the intake side. Position camshaft. RH exhaust camshaft dowel pin at about 10 o-clock; LH exhaust camshaft dowel pin at about 2 o-clock



    Click image to see an enlarged view

    Fig. Camshaft identification-3.5L engine

  14.  
  15. Before installing camshaft brackets, apply sealant to mating surface of No. 1 journal head. Use Genuine RTV silicone sealant or equivalent. Install camshaft brackets in their original positions. Align stamp mark as shown in the figure. If any part of valve assembly or camshaft is replaced, check valve clearance according to reference data. After completing assembly check valve clearance. Valve clearance (Cold):
    NOTE
    Lubricate threads and seat surfaces of camshaft bracket bolts with new engine oil before installing them.



    Click image to see an enlarged view

    Fig. Right camshaft bolt torque sequence-3.5L engine



    Click image to see an enlarged view

    Fig. Left camshaft bolt torque sequence-3.5L engine



    Intake 0.26 - 0.34 mm (0.010 - 0.013 in)
     
    Exhaust 0.29 - 0.37 mm (0.011 - 0.015 in)
     

  16.  
  17. Install intake valve timing control solenoid valves.
  18.  
  19. Install O-rings to cylinder block.
  20.  
  21. Install O-rings to cylinder head.
  22.  
  23. Apply sealant to the hatched portion of rear timing chain case. Apply continuous bead of liquid gasket to mating surface of rear timing chain case. Before installation, wipe off the protruding sealant.
  24.  
  25. Align rear timing chain case with dowel pins, then install on cylinder head and block.
  26.  
  27. Tighten rear chain case bolts.

    Click image to see an enlarged view

    Fig. Rear timing case bolt torque sequence-3.5L engine

    1. Tighten bolts in numerical order shown in the figure.
    2.  
    3. Repeat above step a.
    4.  

  28.  
  29. Reinstall all removed parts in reverse order of removal.
  30.  

 
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