INFINITI QX4 2001 Factory Service Manual

SEM532G
3. Before installing the cylinder head gasket, be sure that No. 1
cylinder is at TDC.
IAt this time, the crankshaft key should face toward the right
bank.
SEM445G
4. Install cylinder heads with new gaskets.
IDo not rotate crankshaft and camshaft separately, or
valves will strike piston heads.
SEM957E
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):
0.11 mm (0.0043 in)
ILubricate threads and seat surfaces of the bolts with new
engine oil.
CYLINDER HEAD
Installation (Cont'd)
EM-48

SEM877EA
SEM878EA
SEM879EA
5. Install cylinder head outside bolts.
ITightening procedure:
a.Tighten all bolts to 98 N´m (10 kg-m, 72 ft-lb).
b.Completely loosen all bolts.
c.Tighten all bolts to 34 to 44 N´m (3.5 to 4.5 kg-m, 25 to 33
ft-lb).
d.Turn all bolts 90 to 95 degrees clockwise.
e.Turn all bolts 90 to 95 degrees clockwise.
ITighten in numerical order shown in the figure.
SEM444G
6. Install camshaft chain tensioners on both sides of cylinder
head.
SEM652F
7. Install exhaust and intake camshafts and camshaft brackets.
IIntake camshaft has a drill mark on camshaft sprocket
mounting flange. Install it on the intake side.
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CYLINDER HEAD
Installation (Cont'd)
EM-49

SEM653F
IIdentification marks are present on camshafts.
Bank INT/EXH ID mark Drill markPaint mark
M1 M2
RHINT R3 Yes Yes No
EXH R3 No No Yes
LHINT L3 Yes Yes No
EXH L3 No No Yes
SEM533G
IPosition camshaft
RH exhaust camshaft dowel pin at about 10 o'clock
LH exhaust camshaft dowel pin at about 2 o'clock
SEM564G
SEM446G
8. Before installing camshaft brackets, apply sealant to mating
surface of No. 1 journal head.
IUse Genuine RTV silicone sealant Part No. 999MP-A7007
or equivalent.
IRefer to ªPOSITION FOR APPLYING LIQUID GASKETº,
EM-21.
IInstall camshaft brackets in their original positions.
Align stamp mark as shown in the figure.
IIf any part of valve assembly or camshaft is replaced,
check valve clearance according to reference data.
After completing assembly check valve clearance. Refer
to ªCheckingº and ªAdjustingº in ªVALVE CLEARANCEº,
EM-52 and 54.
Reference data valve clearance (Cold):
Intake
0.26 - 0.34 mm (0.010 - 0.013 in)
Exhaust
0.29 - 0.37 mm (0.011 - 0.015 in)
ILubricate threads and seat surfaces of camshaft bracket
bolts with new engine oil before installing them.
CYLINDER HEAD
Installation (Cont'd)
EM-50

SEM885EA
SEM886EA
ITighten the camshaft brackets in the following steps.
Step Tightening torque Tightening order
1 1.96 N´m (0.2 kg-m, 17 in-lb)Tighten in the order of 7 to 10,
then tighten 1 to 6.
2 5.88 N´m (0.6 kg-m, 52 in-lb) Tighten in the numerical order.
39.02 - 11.8 N´m (0.92 - 1.20 kg-m,
79.9 - 104.2 in-lb)Tighten in the numerical order.
SEM443G
9. Install CVTC valves.
SEM534G
10. Install O-rings to cylinder block.
SEM447G
11. Install O-rings to cylinder head.
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CYLINDER HEAD
Installation (Cont'd)
EM-51

12. Apply sealant to the hatched portion of rear timing chain case.
IApply continuous bead of liquid gasket to mating surface of
rear timing chain case.
Refer to ªPOSITION FOR APPLYING LIQUID GASKETº,
EM-21.
IBefore installation, wipe off the protruding sealant.
SEM448G
13. Align rear timing chain case with dowel pins, then install on
cylinder head and block.
14. Tighten rear chain case bolts.
a. Tighten bolts in numerical order shown in the figure.
b. Repeat above step a.
15. Reinstall all removed parts in reverse order of removal.
SEM868E
Valve ClearanceNBEM0022CHECKINGNBEM0022S01Check valve clearance while engine is cold and not running.
1. Remove engine cover.
2. Remove air duct with air cleaner case, collectors, hoses, wires,
harnesses, connectors and so on.
3. Remove intake manifold collectors.
4. Remove ignition coils and spark plugs.
5. Remove RH and LH rocker covers.
6. Set No. 1 cylinder at TDC on its compression stroke.
IAlign pointer with TDC mark on crankshaft pulley.
CYLINDER HEAD
Installation (Cont'd)
EM-52

SEM418G
ICheck that valve lifters on No. 1 cylinder are loose and valve
lifters on No. 4 are tight.
If not, turn crankshaft one revolution (360É) and align as above.
SEM893E
7. Check only those valves shown in the figure.
Crank
positionValve
No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
INT EXH INT EXH INT EXH INT EXH INT EXH INT EXH
No. 1 TDCqqq q
SEM139D
IUsing a feeler gauge, measure clearance between valve lifter
and camshaft.
IRecord any valve clearance measurements which are out of
specification. They will be used later to determine the required
replacement adjusting shim.
Valve clearance for checking (Cold):
Intake
0.26 - 0.34 mm (0.010 - 0.013 in)
Exhaust
0.29 - 0.37 mm (0.011 - 0.015 in)
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CYLINDER HEAD
Valve Clearance (Cont'd)
EM-53

SEM894E
8. Turn crankshaft 240É and align as above.
9. Set No. 3 cylinder at TDC on its compression stroke.
10. Check only those valves shown in the figure.
Crank
positionValve
No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
INT EXH INT EXH INT EXH INT EXH INT EXH INT EXH
No. 3 TDCqq qq
SEM958E
11. Turn crankshaft 240É and align as above.
12. Set No. 5 cylinder at TDC on its compression stroke.
13. Check only those valves shown in the figure.
Crank
positionValve
No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
INT EXH INT EXH INT EXH INT EXH INT EXH INT EXH
No. 5 TDCqqqq
14. If all valve clearances are within specification, install the fol-
lowing parts. If they are out of specification, adjust the valve
clearances.
IIntake manifold collectors
IRH and LH rocker covers
IAll spark plugs
IAll ignition coils
SEM449G
ADJUSTINGNBEM0022S02Adjust valve clearance while engine is cold.
1. Turn crankshaft, to position cam lobe on camshaft of valve that
must be adjusted upward.
2. Thoroughly wipe off engine oil around adjusting shim using a
rag.
3. Using a extra-fine screwdriver, turn the round hole of the
adjusting shim in the direction of the arrow.
CYLINDER HEAD
Valve Clearance (Cont'd)
EM-54

SEM869EA
4. Place Tool (A) around camshaft as shown in figure.
Before placing Tool (A), rotate notch toward center of cyl-
inder head (See figure.), to simplify shim removal later.
CAUTION:
Be careful not to damage cam surface with Tool (A).
5. Rotate Tool (A) (See figure.) so that valve lifter is pushed down.
SEM870E
6. Place Tool (B) between camshaft and the edge of the valve
lifter to retain valve lifter.
CAUTION:
ITool (B) must be placed as close to camshaft bracket as
possible.
IBe careful not to damage cam surface with Tool (B).
7. Remove Tool (A).
SEM871E
8. Blow air into the hole to separate adjusting shim from valve
lifter.
SEM872E
SEM145D
9. Remove adjusting shim using a small screwdriver and a mag-
netic finger.
10. Determine replacement adjusting shim size following formula.
IUsing a micrometer determine thickness of removed shim.
ICalculate thickness of new adjusting shim so valve clearance
comes within specified values.
R = Thickness of removed shim
N = Thickness of new shim
M = Measured valve clearance
Intake:
N=R+[Mþ0.30 mm (0.0118 in)]
Exhaust:
N=R+[Mþ0.33 mm (0.0130 in)]
Shims are available in 64 sizes from 2.32 mm (0.0913 in)
to 2.95 mm (0.1161 in), in steps of 0.01 mm (0.0004 in).
ISelect new shim with thickness as close as possible to calcu-
lated value.
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CYLINDER HEAD
Valve Clearance (Cont'd)
EM-55

SEM873E
SEM146D
11. Install new shim using a suitable tool.
IInstall with the surface on which the thickness is stamped
facing down.
SEM874E
12. Place Tool (A) as mentioned in steps 2 and 3.
13. Remove Tool (B).
14. Remove Tool (A).
15. Recheck valve clearance.
Valve clearance:
Unit: mm (in)
Cold Hot* (reference data)
Intake 0.26 - 0.34 (0.010 - 0.013) 0.304 - 0.416 (0.012 - 0.016)
Exhaust 0.29 - 0.37 (0.011 - 0.015) 0.308 - 0.432 (0.012 - 0.017)
*: Approximately 80ÉC (176ÉF)
CYLINDER HEAD
Valve Clearance (Cont'd)
EM-56

Removal and InstallationNBEM0042WARNING:
ISituate vehicle on a flat and solid surface.
IPlace chocks at front and back of rear wheels.
IDo not remove engine until exhaust system has com-
pletely cooled off. Otherwise, you may burn yourself
and/or fire may break out in fuel line.
IFor safety during subsequent steps, the tension of wires
should be slackened against the engine.
IBefore disconnecting fuel hose, release fuel pressure
from fuel line.
Refer to EC-39, ªFuel Pressure Releaseº.
IBefore removing front axle from transmission, place
safety stands under designated front supporting points.
Refer to GI section for lifting points and towing.
IBe sure to hoist engine and transmission in a safe man-
ner.
IFor engines not equipped with engine slingers, attach
proper slingers and bolts described in PARTS CATALOG.
CAUTION:
IWhen lifting engine, be careful not to strike adjacent parts,
especially accelerator wire casing, brake lines, and brake
master cylinder.
IIn hoisting the engine, always use engine slingers in a
safe manner.
IBefore separating engine and transmission, remove
crankshaft position sensor (POS) from the assembly.
IAlways take extra care not to damage edge of crankshaft
position sensor (POS), or ring gear teeth.GI
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ENGINE ASSEMBLY
Removal and Installation
EM-57