2011 INFINITI QX56 engine

EM-84
< REMOVAL AND INSTALLATION >
CAMSHAFT
 Move control shaft (A) to the small stopper and large stopper tocheck that the control shaft functions smoothly.
CAUTION:
Turn VVEL ladder assembly upside down to prevent the drive
shaft from dropping off.
RINK CHECK FOR BACK-LASH (BONDING) Check that the link and the shaft of drive shaft and control shaft are
not fixed.
 Check this by moving drive shaft and control shaft in the axial and
rotation directions.
 If there is an unusualness related to the above three items, replace VVEL ladder assembly & cylinder head
assembly.
NOTE:
VVEL ladder assembly cannot be replaced as a singl e part, because it is machined together with cylinder
head assembly.
INSPECTION AFTER ASSEMBLY
Inspection of Camshaft Sprocket (INT) Oil Groove
CAUTION:
 Perform this inspection only when DTC P0011, P 0021 are detected in self-diagnostic results of CON-
SULT-III and it is directed according to inspection procedure of EC section. Refer to EC-177, "
DTC
Logic".
 Check when engine is cold to prevent burns from the splashing engine oil.
1. Check engine oil level. Refer to LU-7, "
Inspection".
2. Perform the following procedure to prevent the engine from being unintentionally started while checking.
a. Release the fuel pressure. Refer to EC-153, "
Work Procedure".
b. Disconnect ignition coil and injector harness connectors.
3. Remove valve timing control solenoid valve. Refer to EM-61, "
Exploded View".
4. Crank engine, and then check that engine oil comes out from valve timing control solenoid valve hole (A). End crank after
checking.
WARNING:
Be careful not to touch rotati ng parts (drive belt, idler pul-
ley, and crankshaft pulley, etc.).
CAUTION:
 Prevent splashing by using a shop cloth to prevent the worker from injury from en gine oil and to prevent engine
oil contamination.
 Prevent splashing by using a shop cloth to prevent engine oil from being splashed to engine and
vehicle. Especially, be careful not to apply engine oil to rubber parts of drive belt, engine mount-
ing insulator, etc. Wipe engine oil out immediately if it is splashed.
: Engine front
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1 : Valve timing control cover (bank 2)
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Revision: 2010 May2011 QX56

CAMSHAFTEM-85
< REMOVAL AND INSTALLATION >
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5. Perform the following inspection if engine oil does not
come out from valve timing control solenoid valve
oil hole of the valve timing control cover.
 Remove oil filter, and then clean it. Refer to EM-61, "
Exploded View".
 Clean oil groove between oil strainer and valve timing control solenoid valve. Refer to LU-5, "
Engine
Lubrication System" and LU-6, "Engine Lubrication System Schematic".
6. Remove components between valve timing control solenoid valve and camshaft sprocket, and then check each oil groove for clogging.
 Clean oil groove if necessary. Refer to LU-5, "
Engine Lubrication System" and LU-6, "Engine Lubrica-
tion System Schematic".
7. After inspection, install removed parts in the reverse order.
Inspection for Leakage
The following are procedures for chec king fluid leakage, lubricant leakage.
 Before starting engine, check oil/fluid levels including engine coolant and engine oil. If any are less than the
required quantity, fill them to the specified level. Refer to MA-10, "
Fluids and Lubricants".
 Follow the procedure below to check for fuel leakage.
- Turn ignition switch to the “ON” position (with engi ne stopped). With fuel pressure applied to fuel piping,
check for fuel leakage 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. NOTE:
If hydraulic pressure inside chain tensioner drops after removal/installation, slack in guide may generate a
pounding noise during and just after the engine start. However, this does not indicate a malfunction. The
noise will stop after hydraulic pressure rises.
 Warm up engine thoroughly to check that there is no leak age of fuel, or any oil/fluids including engine oil and
engine coolant.
 Bleed air from lines and hoses of applicable lines, such as in cooling system.
 After cooling down engine, again check oil/fluid levels including engine oil and engine coolant. Refill them to
the specified level, if necessary.
Summary of the inspection items:
* Power steering fluid, brake fluid, etc. Items Before starting engine Engine running After engine stopped
Engine coolant Level Leakage Level
Engine oil Level Leakage Level
Transmission /
transaxle fluid AT & CVT Models Leakage Level / Leakage Leakage
MT Models Level / Leakage Leakage Level / Leakage
Other oils and fluids* Level Leakage Level
Fuel Leakage Leakage Leakage
Revision: 2010 May2011 QX56

EM-86
< REMOVAL AND INSTALLATION >
CYLINDER HEAD
CYLINDER HEAD
Exploded ViewINFOID:0000000006289571
CAUTION:
A high degree of precision is required for a valve on the intake side. Never remove the valve related
parts unless necessary.
1. Valve lifter (EXH) 2. Valve collet (EXH) 3. Valve spring retainer (EXH)
4. Valve oil seal (EXH) 5. Valve spring (with valve spring seat)
(EXH)6. Valve guide (EXH)
7. Spark plug 8. Valve lifter (INT) 9. Valve collet (INT)
10. Valve spring retainer (INT) 11. Valve oil seal (INT) 12. Valve spring (with valve spring seat)
(INT)
13. Cylinder head bolt 14. Cylinder head (bank 2) 15. Valve seat (EXH)
16. Valve (EXH) 17. Cylinder head gasket (bank 2) 18. Oil filter (for VVEL ladder assembly)
19. Cylinder block 20. Valve (INT) 21. Valve seat (INT)
22. Cylinder head gasket (bank 1) 23. Cylinder head (bank 1) 24. Engine coolant temperature sensor
A. Comply with the installation proce-
dure when tightening. Refer to
EM-
87, "Removal and Installation".
Refer to GI-4, "
Components" for symbol marks in the figure.
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Revision: 2010 May2011 QX56

CYLINDER HEADEM-87
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NOTE:
 As for replacement of parts on the intake side as
shown in the exploded view, replace VVEL ladder assem-
bly & cylinder head assembly. (Only valve oil seals are replaceable as a single part.)
 VVEL ladder assembly cannot be replaced as a singl e part, because it is machined together with cylinder
head assembly.
Removal and InstallationINFOID:0000000006289572
REMOVAL
1. Remove the following parts:  Rocker cover and spark plug: Refer to EM-33, "
Exploded View".
 Intake manifold: Refer to EM-30, "
Exploded View".
 Exhaust manifold: Refer to EM-40, "
Exploded View".
 Water inlet and thermostat housing: Refer to CO-20, "
Exploded View".
 Water pipe and heater pipe: Refer to CO-20, "
Exploded View".
 Timing chain: Refer to EM-61, "
Exploded View".
 Camshaft (EXH) and VVEL ladder assembly: Refer to EM-74, "
Exploded View".
2. Remove cylinder head.  Loosen mounting bolts in reverse order as shown in the figure.
 Use TORX socket and power tool.
3. Remove cylinder head gaskets.
4. Remove oil filter (for VVEL ladder asse mbly) from cylinder block, if necessary.
5. Remove valve lifter.  Identify installation positions, and store them without mixing them up.
INSTALLATION
1. Install oil filter (for VVEL l adder assembly) (1) in the direction
shown in the figure, if removed.
 Check that the oil filter does not protrude from the upper sur-
face of cylinder block (2) after installation.
A: Bank 2
B: Bank 1
: Engine front
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Revision: 2010 May2011 QX56

EM-88
< REMOVAL AND INSTALLATION >
CYLINDER HEAD
2. Install new cylinder head gaskets.
3. Install cylinder head as per the following: CAUTION:
 If cylinder head bolts are re-used, check their ou ter diameters before installation. Refer to EM-92,
"Inspection".
 Before installing cylinder head, inspect cylinder head distortion. Refer to EM-92, "
Inspection".
 Tighten cylinder head bolts in numerical order as shown in fig- ure.
 Use TORX socket.
a. Apply new engine oil to threads and seat surfaces of cylinder head bolts.
b. Tighten all cylinder head bolts.
c. Tighten all cylinder head bolts (clockwise).
d. Completely loosen all cylinder head bolts.
CAUTION:
In step “d”, loosen bolts in the reverse order of that indi-
cated in the figure.
e. Tighten all cylinder head bolts.
f. Tighten all cylinder head bolts (clockwise).
g. Tighten all cylinder head bolts again (clockwise).
CAUTION:
Check the tightening angle us ing the angle wrench [SST:
KV10112100 (BT8653-A)] (A). Never make judgment by
visual inspection.
 Check tightening angle indicated on the angle wrench indica- tor plate.
4. Install valve lifter.  Install it in the original position.
5. Install in the reverse order of removal.
A: Bank 2
B: Bank 1
: Engine front
: 40.0 N·m (4.1 kg-m, 30 ft-lb)
Angle tightening: 75 degrees : 0 N·m (0 kg-m, 0 ft-lb)
: 40.0 N·m (4.1 kg-m, 30 ft-lb)
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Angle tightening: 90 degrees
Angle tightening: 90 degrees
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Revision: 2010 May2011 QX56

EM-92
< REMOVAL AND INSTALLATION >
CYLINDER HEAD
a. Apply new engine oil on new valve oil seal joint and seal lip.
b. Using the valve oil seal drift [SST: KV10115600 (J-38958)] (A),press fit valve seal to height (b) shown in figure.
4. Install valve. NOTE:
Larger diameter valves are for intake side.
5. Install valve spring (with valve spring seat).  Install narrow pitch (B) end [paint mark (C)] to cylinder headside (valve spring seat side).
6. Install valve spring retainer.
7. Install valve collet.  Compress valve spring with the valve spring compressor [SST:
KV10116200 (J26336-A)] (A), the attachment [SST:
KV10115900 (J26336-20)] (C) and the adapter [SST:
KV10109220 ( — )] (B). Install valve collet with a magnet
hand.
CAUTION:
When working, take care not to damage valve lifter holes.
 Tap valve stem edge lightly with plastic hammer after installa- tion to check its installed condition.
InspectionINFOID:0000000006289573
INSPECTION AFTER DISASSEMBLY
Cylinder Head Bolt s Outer Diameter
 Cylinder head bolts are tightened by plastic zone tightening
method. Whenever the size difference between (B) and (A)
exceeds the limit, replace them with new one.
 If reduction of outer diameter appears in a position other than (A),
use it as (A) point. Height (b)
Intake, Exhaust : 14.3 - 14.9 mm (0.563 - 0.587 in)
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A : Wide pitch
: Cylinder head side
Paint mark color
Intake : Light green
Exhaust : Light blue
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Limit [(B) - (A)] : 0.18 mm (0.0071 in)
c : 55 mm (2.17 in)
d : 12 mm (0.47 in)
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Revision: 2010 May2011 QX56

CYLINDER HEADEM-93
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Cylinder Head Distortion
NOTE:
When performing this inspection, cylinder block distortion should be also checked. Refer to
EM-115, "
Inspec-
tion".
1. Using a scraper, wipe out oil, scale, gasket, s ealant and carbon deposits from surface of cylinder head.
CAUTION:
Never allow gasket fragments to enter engine oil or engine coolant passages.
2. At each of several locations on bottom surface of cylinder head, measure the distortion in six directi ons (A), (B), (C), (D), (E), and
(F).
 If it exceeds the limit, replace VVEL ladder assembly & cylinder head assembly.
NOTE:
Cylinder head assembly cannot be replaced as a single part,
because it is machined together with VVEL ladder assembly.
Valve Dimensions
 Check the dimensions of each valv e. For the dimensions, refer to EM-135, "CylinderHead".
 If dimensions are out of the standard.
- Replace valve (EXH) and check valve seat contact. Refer to "VALVE SEAT CONTACT". (Exhaust side)
- Replace VVEL ladder assembly & cylinder head assembly. Refer to EM-86, "
Exploded View". (Intake side)
NOTE:
Since the valve (INT) cannot be replaced by the pi ece, VVEL ladder assembly & cylinder head assembly
replacement are required.
Valve Guide Clearance
Valve Stem Diameter
 Measure the diameter of valve stem with micrometer (A).
Valve Guide Inner Diameter
 Measure the inner diameter of valve guide with bore gauge.
Valve Guide Clearance
 (Valve guide clearance) = (Valve guide inner diameter) – (Valve
stem diameter)
 If the calculated value exceeds the limit.
- Replace valve (EXH) and/or valve guide (EXH). Refer to EM-86, "
Exploded View". (Exhaust side)
- Replace VVEL ladder assembly & cylinder head assembly. Refer to EM-86, "
Exploded View". (Intake side)
NOTE:
Since the valve (INT) and valve guide (INT) cannot be repl aced by the piece, VVEL ladder assembly & cylin-
der head assembly replacement are required.
Valve Seat Contact
 After confirming that the dimensions of valve guides and valves are within the specifications, perform this
procedure.
 Apply prussian blue (or white lead) onto contacting surfac e of valve seat to check the condition of the valve
contact on the surface. Limit : Refer to
EM-135, "
CylinderHead".
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Standard : Refer to EM-135, "CylinderHead".
Standard : Refer to EM-135, "
CylinderHead".
Standard : Refer to EM-135, "
CylinderHead".
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Revision: 2010 May2011 QX56

EM-94
< REMOVAL AND INSTALLATION >
CYLINDER HEAD
 Check if the contact area band is continuous all around the circum-ference.
- If not, grind to adjust valve fitting and check again. If the contacting surface still has “NG” conditions even after the re-check, replace
valve seat (EXH). Refer to EM-86, "
Exploded View". (Exhaust
side)
- If not, replace VVEL ladder assembly & cylinder head assembly. Refer to EM-86, "
Exploded View". (Intake side)
NOTE:
Since the valve seat (INT) cannot be replaced by t he piece, VVEL ladder assembly & cylinder head assem-
bly replacement are required.
Valve Spring (with valve spring seat) Squareness
 Set a try square (A) along the side of valve spring (with valve
spring seat) and rotate spring. Measure the maximum clearance
between the top of spring and try square.
 If it exceeds the limit.
- Replace valve spring (with valve spring seat) (EXH). Refer to EM-
86, "Exploded View". (Exhaust side)
- Replace VVEL ladder assembly & cylinder head assembly. Refer
to EM-86, "
Exploded View". (Intake side)
NOTE:
Since the valve spring (with valve spring seat) (INT) c annot be replaced by the piece, VVEL ladder assembly
& cylinder head assembly replacement are required.
Valve Spring Dimensions and Valve Spring Pressure Load
 Check the valve spring (with valve spring seat) pressure at speci- fied spring height.
 If the installation load or load with valve open is out of the stan- dard.
- Replace valve spring (with valve spring seat) (EXH). Refer to EM-
86, "Exploded View". (Exhaust side)
- Replace VVEL ladder assembly & cylinder head assembly. Refer to EM-86, "
Exploded View". (Intake side)
NOTE:
Since the valve spring (with valve spring seat) (INT) c annot be replaced by the piece, VVEL ladder assembly
& cylinder head assembly replacement are required.
INSPECTION AFTER ASSEMBLY
Inspection for Leakage
The following are procedures for checking fluid leakage, lubricant leakage.
 Before starting engine, check oil/fluid levels includi ng engine coolant and engine oil. If any are less than the
required quantity, fill them to the specified level. Refer to MA-10, "
Fluids and Lubricants".
 Follow the procedure below to check for fuel leakage.
- Turn ignition switch to the “ON” position (with engi ne stopped). With fuel pressure applied to fuel piping,
check for fuel leakage at connection points.
- Start engine. With engine speed increased, che ck again for fuel leakage at connection points.
 Run engine to check for unusual noise and vibration. NOTE:
A: OK
B: NG
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B : Contact
Limit : Refer to EM-135, "CylinderHead".
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Standard
: Refer to EM-135, "
CylinderHead".
SEM113
Revision: 2010 May2011 QX56