INFINITI QX56 2008 Factory Service Manual

EM-68
< ON-VEHICLE REPAIR >
CYLINDER HEAD
CYLINDER HEAD
Exploded ViewINFOID:0000000006055158
Removal and InstallationINFOID:0000000006055159
REMOVAL
1. Remove the engine assembly from the vehicle. Refer to EM-78, "Removal and Installation".
2. Remove the following components and related parts: • Drive belt auto tensioner and idler pulley. Refer to EM-14, "
Drive Belt Auto Tensioner and Idler Pulley".
• Generator assembly and bracket. Refer to CHG-22, "
Removal and Installation".
• Fuel tube and fuel injector assembly. Refer to EM-40, "
Removal and Installation".
• Intake manifold. Refer to EM-26, "
Removal and Installation".
• Thermostat housing and hose. Refer to CO-22, "
Removal and Installation".
• Rocker cover. Refer to EM-38, "
Removal and Installation".
• Oil pan and oil strainer. Refer to EM-33, "
Removal and Installation".
3. Remove the crankshaft pulley, front cover, oil pump, and timing chain. Refer to EM-45, "
Removal and
Installation".
4. Remove the camshaft sprockets and camshafts. Refer to EM-53, "
Removal and Installation".
5. Remove the cylinder head bolts in reverse of order shown.
6. Remove the cylinder heads.
INSPECTION AFTER REMOVAL
Cylinder Head Bolts Diameter
1. Harness bracket 2. Engine coolant temperature sensor 3. Washer
4. Cylinder head gasket (LH) 5. Cylinder head (RH) 6. Cylinder head bolt
7. Cylinder head gasket (RH) 8. Cylinder head (LH)
KBIA2528E
PBIC0068E
Revision: March 2010 2008 QX56

CYLINDER HEADEM-69
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• Cylinder head bolts are tightened by plastic zone tightening
method. Whenever the size difference between d1 and d2 exceeds
the limit, replace the bolt with a new one.
• If reduction of diameter appears in a position other than d2, use it as d2 point.
INSTALLATION
1. Install a new cylinder head gasket.
2. Install the cylinder head. Follow the steps below to tighten the bolts in the numerical order shown.
CAUTION:
• If cylinder head bolts are re-used, check their diameters
before installation. Refer to "Cylinder Head Bolts Diame-
ter".
a. Apply engine oil to threads and seating surface of the bolts.
b. Measure the tightening angle using Tool. CAUTION:
Measure the tightening angl e using Tool. Do not measure
visually.
3. Installation of the remaining components is in the reverse order of removal.
INSPECTION AFTER INSTALLATION
• Before starting engine, check oil/fluid levels incl uding engine coolant and engine oil. If less than required
quantity, fill to the specified level. Refer to MA-12, "
Fluids and Lubricants".
• Use procedure below to check for fuel leakage.
• Turn ignition switch ON (with engine stopped). With fuel pressure applied to fuel piping, check for fuel leak-
age at connection points.
• Start engine. With engine speed increased, check again for fuel leakage at connection points.
• Run engine to check for unusual noise and vibration.
• Warm up engine thoroughly to make sure there is no leak age of fuel, exhaust gas, or any oils/fluids including
engine oil and engine coolant.
• Bleed air from passages in lines and hoses, such as in cooling system.
• After cooling down engine, again check oil/fluid levels including engine oil and engine coolant. Refill to spec- ified level, if necessary.
• Summary of the inspection items: Limit (d1 - d2) : 0.23 mm (0.0091 in)
KBIA0189E
PBIC0068E
Step a : 44.1 N·m (4.5 kg-m, 33 ft-lb)
Step b : 70°
clockwise
Step c : Loosen in the reverse order of tightening.
Step d : 44.1 N·m (4.5 kg-m, 33 ft-lb)
Step e : 60 ° clockwise
Step f : 60° clockwise
WBIA0603E
Tool number : KV10112100 (BT-8653-A)
Revision: March 2010 2008 QX56

EM-70
< ON-VEHICLE REPAIR >
CYLINDER HEAD
*Power steering fluid, brake fluid, etc.
Disassembly and AssemblyINFOID:0000000001538829
DISASSEMBLY
1. Remove the spark plug. Refer to EM-16, "Removal and Installation".
2. Remove the valve lifter. • Identify the installation positions, and store them without mixing them up.
Item Before starting engine Engine runningAfter engine stopped
Engine coolant LevelLeakage Level
Engine oil LevelLeakage Level
Transmission/
transaxle fluid A/T and CVT Models
LeakageLevel/Leakage Leakage
M/T Models Level/Leakage LeakageLevel/Leakage
Other oils and fluids* LevelLeakage Level
Fuel LeakageLeakage Leakage
Exhaust gas —Leakage —
1. Spark plug 2. Valve lifter3. Valve collet
4. Valve spring retainer 5. Valve spring6. Valve spring seat
7. Valve oil seal 8. Valve guide9. Valve seat
10. Valve (INT) 11. Valve (EXH)12. Cylinder head (LH bank)
13. Spark plug tube 14. Cylinder head (RH bank)
WBIA0470E
Revision: March 2010 2008 QX56

CYLINDER HEADEM-71
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3. Remove the valve collet using Tools.
CAUTION:
When working, take care not to damage valve lifter holes.
4. Remove the valve spring retainer, valve spring and valve spring seat.
5. Inspect the valve guide clearance. Refer to EM-72, "
Inspection After Disassembly".
6. Push the valve stem to the combustion chamber side, and remove the valve. • Identify the installation positions, and store them without mixing them up.
7. Remove the valve oil seal using Tool.
8. Replace the valve seat if necessary. Refer to EM-72, "
Inspection After Disassembly".
9. Replace the valve guide if necessary. Refer to EM-72, "
Inspection After Disassembly".
10. Remove the spark plug tube, as necessary. • Remove the spark plug tube out of the cylinder head using suitable tool.
CAUTION:
• Do not damage the cylinder head.
• Do not remove the spark plug tube unless absolutely necessary. Once removed, the spark plug tube will be deformed and cannot be reused.
ASSEMBLY
1. Install the valve guide if necessary. Refer to EM-72, "Inspection After Disassembly".
2. Install the valve seat if necessary. Refer to EM-72, "
Inspection After Disassembly".
3. Install the valve oil seal using Tool.
• Apply new engine oil on the new valve oil seal joint and seallip.
• Install the valve oil seal to the specified height "H".
4. Install the valves in their original position.
5. Install the valve spring seats. Tool number
: KV10116200 (J-26336-A)
: KV10115900 (J-26336-20)
: KV10109220 ( — )
Tool number : KV10107902 (J-38959)
WBIA0578E
WBIA0478E
Tool number : KV10115600 (J-38958)
Height "H" (without valve spring installed) Intake and exhaust : 14.3 - 14.9 mm (0.563 - 0.587 in)
WBIA0490E
Revision: March 2010 2008 QX56

EM-72
< ON-VEHICLE REPAIR >
CYLINDER HEAD
6. Install the valve springs.• Install the narrow pitch end (paint mark side) to the cylinderhead side.
7. Install the valve spring retainers.
8. Install the valve collet using Tools.
CAUTION:
When working, take care not to damage valve lifter holes.
9. Install the valve lifters. • Install the removed parts in their original locations.
• If installing new lifters, select the correct size lifter for proper valve clearance. Refer to EM-18, "
Va l v e
Clearance".
10. Install the spark plug tube if necessary, following the procedure below.
a. Remove any old liquid gasket adhering to the cylinder-head spark plug tube hole.
b. Apply liquid gasket to area within approximately 12 mm (0.47 in) from the edge of the spark plug tube
press-fit side.
Use Genuine RTV Silicone Seal ant or equivalent. Refer to GI-15, "
Recommended Chemical Prod-
ucts and Sealants".
c. Press-fit the spark plug tube to the specified height “H” using suitable tool.
CAUTION:
• When press-fitting, take care not to deform the spark plugtube.
• After press-fitting, wipe off any liquid gasket protruding
onto the cylinder-head upper face.
11. Install the spark plugs.
Inspection After DisassemblyINFOID:0000000001538830
CYLINDER HEAD DISTORTION
1. Remove any oil, scale, gasket, sealant and carbon deposits from the cylinder head surface. CAUTION:
Do not allow any debris to en ter the oil or coolant passages.
SEM085D
Tool number : KV10116200 (J-26336-A)
: KV10115900 (J-26336-20)
: KV10109220 ( — )
WBIA0578E
Standard press-fit height “H” :38.4 - 39.4 mm (1.512 - 1.551 in)
KBIA1248E
Revision: March 2010 2008 QX56

CYLINDER HEADEM-73
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2. Measure the bottom surface of the cylinder head for distortion in
six directions as shown, using suitable tools.
• If measurement exceeds the limit, replace the cylinder head.
VALVE DIMENSIONS
• Check the dimensions of each va lve. Follow the "VALVE DIMEN-
SIONS" procedure.
• If the dimensions are out of the standard, replace the valve.
VALVE GUIDE CLEARANCE
Valve Stem Diameter
Measure the diameter of the va lve stem using suitable tool.
Valve Guide Inside Diameter
Measure the inside diameter of the valve guide using suitable tool.
Valve Guide Clearance
• (Valve guide clearance) = (Valve guide inside diameter) – (Valve stem diameter).
• If the calculated value exceeds the limit, replace valve and/or valve guide. When the valve guide must be
replaced, follow the "VALVE GUIDE REPLACEMENT" procedure. Standard : 0.03 mm (0.0012 in)
Limit : 0.1mm (0.004 in)
PBIC0075E
SEM188A
Standard
Intake : 5.965 - 5.980 mm (0.2348 - 0.2354 in)
Exhaust : 5.955 - 5.970 mm (0.2344 - 0.2350 in)
SEM938C
StandardIntake and Exhaust : 6.000 - 6.018 mm (0.2362 - 0.2369 in)
Valve guide clearance:
Standard Intake : 0.020 - 0.053 mm (0.0008 - 0.0021 in)
Exhaust : 0.030 - 0.063 mm (0.0012 - 0.0025 in)
Limit Intake : 0.08 mm (0.0031 in)
Exhaust : 0.09 mm (0.0035 in)
Revision: March 2010 2008 QX56

EM-74
< ON-VEHICLE REPAIR >
CYLINDER HEAD
VALVE GUIDE REPLACEMENT
When the valve guide is removed, replace it with an oversized (0.2 mm, 0.008 in) valve guide.
1. To remove the valve guide, heat the cylinder head to 110° to
130° C (230° to 266°F) by soaking it in heated oil.
2. Remove the valve guide using suitable tool. CAUTION:
Cylinder head contains heat. When working, wear protec-
tive equipment to avo id getting burned.
3. Ream the cylinder head valve guide hole using suitable tool.
4. Heat the cylinder head to 110 ° to 130° C (230° to 266° F) by
soaking it in heated oil.
SEM008A
SEM931C
Valve guide hole diameter:
Standard
Intake and exhaust : 9.975 - 9.996 mm (0.3927 - 0.3935 in)
Oversize (service) Intake and exhaust : 10.175 - 10.196 mm (0.4006 - 0.4014 in)
SEM932C
SEM008A
Revision: March 2010 2008 QX56

CYLINDER HEADEM-75
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5. Press the valve guide from the camshaft side to the dimensions
as shown.
CAUTION:
Cylinder head contains heat . When working, wear protec-
tive equipment to avo id getting burned.
6. Ream the cylinder head valve guide using suitable tool.
VALVE SEAT CONTACT
• After confirming that the dimensions of the valve guides and valves are within specifications, perform this procedure.
• Apply prussian blue (or white lead) onto the contacting surface of the valve seat to check the condition of the valve contact on the
surface.
• Check if the contact area band is continuous all around the circum- ference.
• If not, grind to adjust the valve fi t and check again. If the contacting
surface still has NG conditions even after the re-check, replace the
valve seat.
VALVE SEAT REPLACEMENT
When the valve seat is removed, replace it with oversized (0.5 mm, 0.020 in) valve seat.
1. Bore out the old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in the cylinder head. Set the machine depth stop to ensure this.
2. Ream the cylinder head recess diameter for service valve seat.
• Be sure to ream in circles concentric to the valve guide center.
• This will enable valve seat to fit correctly.
KBIA2530E
Valve guide inside diameter:
Intake and exhaust : 6.000 - 6.018 mm (0.2362 - 0.2369 in)
SEM932C
SBIA0322E
Oversize [0.5 mm (0.020 in)] (Service):
Intake : 38.500 - 38.516 mm (1.5157 - 1.5164 in)
Exhaust : 32.700 - 32.716 mm (1.2874 - 1.2880 in)
SEM795A
Revision: March 2010 2008 QX56

EM-76
< ON-VEHICLE REPAIR >
CYLINDER HEAD
3. Heat the cylinder head to 110° to 130° C (230° to 266° F) by
soaking it in heated oil.
4. Cool the valve seats well with dry ice. Force fit the valve seat into the cylinder head. CAUTION:
• Avoid directly touching cold valve seats.
• Cylinder head contains heat. When working, wear protective eq uipment to avoid getting burned.
5. Finish the seat to the specified dimensions using suitable tool. Follow the "VALVE SEAT CONTACT" procedure.
CAUTION:
When using valve seat cutter, firmly grip the cutter handle
with both hands. Then, pr ess on the contacting surface all
around the circumference to cu t in a single drive. Improper
pressure on the cutter or cutting many different times may
result in stage valve seat.
6. Grind to obtain the dimensions indicated as shown. • Using compound, grind to adjust valve fitting.
7. Check again for normal contact. Follow the "VALVE SEAT CONTACT" procedure.
VALVE SPRING SQUARENESS
SEM008A
SEM934C
KBIA2531E
KBIA2544E
Revision: March 2010 2008 QX56

CYLINDER HEADEM-77
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• Set try square along the side of valve spring and rotate the spring.
Measure the maximum clearance between the top face of spring
and try square.
• If measurement is not within specifications, replace the valve spring.
VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
• Check the valve spring pressure at the specified spring height.
• If measurement is not within specifications, replace the valve spring. Limit : Less than 2.2 mm (0.087 in)
PBIC0080E
Standard:
Intake and exhaustFree height: 50.58 mm (1.9913 in)
Installation height: 37.0 mm (1.457 in)
Installation pressure: 165.8 - 187.0 N (16.9 - 19.1 kg, 37- 42 lb)
Height during valve open: 28.2 mm (1.110 in)
Load with valve open: 314.8 - 355.0 N (32.1 - 36.2 kg, 71 - 80 lb)
SEM113
Revision: March 2010 2008 QX56