2004 INFINITI QX56 service

PREPARATION
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Commercial Service ToolsEBS00IL6
(Kent-Moore No.)
Tool nameDescription
Power toolLoosening bolts and nuts
Spark plug wrench Removing and installing spark plug
(J-24239-01)
Cylinder head bolt wrenchLoosening and tightening cylinder head bolt,
and use with angle wrench [SST:
KV10112100 (BT-8653-A)]
a: 13 (0.51) dia.
b: 12 (0.47)
c: 10 (0.39)
Unit: mm (in)
Valve seat cutter set Finishing valve seat dimensions
Pulley pullerRemoving crankshaft pulley
Piston ring expander Removing and installing piston ring
Valve guide drift Removing and installing valve guide
Intake & Exhaust:
a: 9.5 mm (0.374 in) dia.
b: 5.5 mm (0.217 in) dia.
PBIC0190E
S-NT047
NT583
S-NT048
ZZA0010D
S-NT030
S-NT015

CYLINDER HEAD
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CYLINDER HEADPFP:11041
On-Vehicle ServiceEBS00ILS
CHECKING COMPRESSION PRESSURE
1. Warm up engine thoroughly. Then stop engine.
2. Release fuel pressure. Refer to EC-46, "
FUEL PRESSURE RELEASE" .
a. Remove fuel pump fuse, and start engine.
Refer to PG-78, "
FUSE AND RELAY BOX" or fuel pump fuse location.

Let fuel pump fuse removed until the end of step 7.
b. After engine stalls, crank it two or three times to release all fuel pressure.
3. Remove ignition coil and spark plug from each cylinder.
Refer to EM-27, "
REMOVAL" .
4. Connect engine tachometer (not required in use of CONSULT-II).
5. Install compression tester with Tool into spark plug hole.
6. With accelerator pedal fully depressed, turn ignition switch to “START” for cranking. When the gauge
pointer stabilizes, read the compression pressure and engine rpm. Perform these steps to check each cyl-
inder.
Unit: kPa (kg/cm2 , psi) /rpm
CAUTION:
Always use a fully charged battery to obtain specified engine speed.

If the engine speed is out of specified range, check battery liquid for proper gravity. Check engine
speed again with normal battery gravity.

If compression pressure is below minimum value, check valve clearances and parts associated with
combustion chamber (valve, valve seat, piston, piston ring, cylinder bore, cylinder head, cylinder head
gasket). After the checking, measure compression pressure again.

If some cylinders have low compression pressure, pour small amount of engine oil into the spark plug
hole of the cylinder to re-check it for compression.
–If the added engine oil improves the compression, the piston rings may be worn out or damaged. Check
the piston rings and replace if necessary.
–If the compression pressure remains at low level despite the addition of engine oil, the valves may be
malfunctioning. Check the valves for damage. Replace the valve or valve seat accordingly.

If two adjacent cylinders have respectively low compression pressure and their compression remains
low even after the addition of engine oil, the gaskets may be leaking, or valve in adjacent cylinders may
be damaged. Inspect and repair as required.
7. After inspection is complete, install removed parts. Installation is in the reverse order of removal.
8. Start engine, and confirm that engine runs smoothly.
9. Perform trouble diagnosis. If DTC appears, erase it. Refer to EC-71, "
TROUBLE DIAGNOSIS" . Tool number : EG15050500 (J-45402)
WBIA0605E
Standard MinimumDeference limit
between cylinders
1,520 (15.5, 220) / 200 1,324 (13.5, 192) / 200 98 (1.0, 14) / 300

CYLINDER HEAD
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2. Remove the valve guide using suitable tool.
CAUTION:
Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.
3. Ream cylinder head valve guide hole using suitable tool.
4. Heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in
heated oil.
5. Press valve guide from camshaft side to dimensions as shown.
CAUTION:
Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.
6. Ream cylinder head valve guide hole using suitable tool.
SEM 93 1C
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)
SEM 93 2C
SEM 00 8A
KBIA2530E
Valve guide hole diameter:
Intake and exhaust : 6.000 - 6.018 mm
(0.2362 - 0.2369 in)
SEM 93 2C

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CYLINDER HEAD
2004 QX56
VALVE SEAT CONTACT

After confirming that the dimensions of valve guides and valves
are within specifications, perform this procedure.

Apply prussian blue (or white lead) onto contacting surface of
valve seat to check the condition of the valve contact on the sur-
face.

Check if the contact area band is continuous all around the cir-
cumference.

If not, grind to adjust valve fitting and check again. If the contact-
ing surface still has NG conditions even after the re-check,
replace valve seat.
VALVE SEAT REPLACEMENT
When valve seat is removed, replace with oversized (0.5 mm, 0.020 in) valve seat.
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.
2. Ream 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.
3. Heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in
heated oil.
4. Provide valve seats cooled well with dry ice. Force fit valve seat into cylinder head.
CAUTION:

Avoid directly touching cold valve seats.

Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.
5. Finish seat to the specified dimensions using suitable tool. Refer
to EM-103, "
Valve Seat" .
CAUTION:
When using valve seat cutter, firmly grip the cutter handle
with both hands. Then, press on the contacting surface all
around the circumference to cut in a single drive. Improper
pressure on the cutter or cutting many different times may
result in stage valve seat.
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)
SEM 79 5A
SEM 00 8A
SEM 93 4C

EM-82Revision: August 2007
CYLINDER BLOCK
2004 QX56
19. Install drive plate.

Align dowel pin of crankshaft rear end with pin holes of each
parts to install.

Install drive plate, reinforcement plate and pilot converter (if
not installed in step 4) as shown.

Face chamfered or rounded edge side to crankshaft.
How to Select Piston and Bearing EBS00ILY
DESCRIPTION
*For the service parts, the grade for fitting cannot be selected between a piston pin and a connecting rod.
(Only 0 grade is available.) The information at the shipment from the plant is described as a reference.

The identification grade stamped on each part is the grade for the dimension measured in new condition.
This grade cannot apply to reused parts.

For reused or repaired parts, measure the dimension accurately. Determine the grade by comparing the
measurement with the values of each selection table.

For details of the measurement method of each part, the reuse standards, and the selection method of the
selective fitting parts, refer to the text.
KBIA2494E
KBIA2537E
Connecting points Connecting parts Selection items Selection methods
Between cylinder block to
crankshaftMain bearingMain bearing grade (bearing
thickness)Determined by match of cylin-
der block bearing housing
grade (Housing inside diame-
ter) and crankshaft journal
grade (journal outside diame-
ter)
Between crankshaft to connect-
ing rodConnecting rod bearingConnecting rod bearing grade
(bearing thickness)Connecting rod bearing grade
= crankshaft pin grade (pin
diameter). No grade exists for
inside diameter of connecting
rod large end.
Between cylinder block to pis-
tonPiston and piston pin assembly.
The piston is available together
with piston pin as an assembly.Piston grade (piston diameter)Piston grade = cylinder bore
grade (diameter of bore)
*Between piston to connecting
rod———

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HOW TO SELECT PISTON
Piston Selective Fitting When New Cylinder Block is Used:

Check the cylinder bore grade on the bottom face of cylinder
block, and select the piston of the same grade.
When Cylinder Block is Reused
1. Measure the cylinder block bore diameter.
2. Determine the bore grade by comparing the measurement with the values under the “Cylinder bore diam-
eter” of the piston selection table. Use oversized piston if clearance of standard grade piston is outside the
specified value.
Piston Selection Table
Unit: mm (in)
CAUTION:
Oversize must be used in all cylinders when using oversized parts.
NOTE:

The piston is available together with piston pin as an assembly.

The piston pin (piston pin bore) grade is provided only for the parts installed at the plant. For service parts,
no grades can be selected (Only 0 grade is available.).

Hone cylinder to obtain specified clearance between piston and cylinder bore when using an oversized
piston. Be sure to use the same oversized piston rings.
KBIA2495E
KBIA2496E
Grade number (Mark) 1 2 3
Cylinder bore diameter 98.000-98.010 (3.8583-3.8587) 98.010-98.020 (3.8587-3.8590) 93.020-98.030 (3.8590-3.8594)
Piston diameter 97.980-97.990 (3.8575-3.8579) 97.990-98.000 (3.8579-3.8583) 98.000-98.010 (3.8583-3.8587)
Piston oversize (Service) : 0.20 mm (0.0079 in)

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Undersize Bearings Usage Guide

When the specified oil clearance is not obtained with standard size connecting rod bearings, use under-
size (US) bearings.

When using undersize bearing, measure the bearing inside diameter with bearing installed, and grind the
crankshaft pin so that the oil clearance satisfies the standard.
Bearing undersize table
Unit: mm (in)
CAUTION:
In grinding the crankshaft pin to use undersize bearings, keep
the fillet R (All crankshaft pins).
HOW TO SELECT MAIN BEARING
When New Cylinder Block and Crankshaft are Used
1. Apply main bearing housing grade on bottom face of cylinder
block to the row in the "Main Bearings Selection Table".
2. Apply journal diameter grade on crankshaft front to the column
in the "Main Bearings Selection Table".
3. Read the symbol at the cross point of selected row and column in the "Main Bearings Selection Table".
CAUTION:

Initial clearance for No.1, 5 journal and No. 2, 3, 4 journal is different. Use two different selection
lists for each part.

No.1, 5 journal and No. 2, 3, 4 journal have the same signs but different measures. Do not con-
fuse.
4. Apply the symbol to the "Main Bearings Grade Table" to select.
NOTE:

Grade list applies to all journals.

Service parts are available as a set of both upper and lower.
2 1.506 - 1.509 (0.0593 - 0.0594) Green
3 1.509 - 1.512 (0.0594 - 0.0595) Yellow
Undersize Thickness
0.25 (0.0098) 1.627 - 1.635 (0.0641 - 0.0644)
Fillet R : 1.5 - 1.7 mm (0.059 - 0.067 in)
PB I C 0 111E
KBIA2495E
PBIC0 110 E

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CYLINDER BLOCK
2004 QX56
Piston and Piston Pin Clearance
(Piston pin clearance) = (Piston pin hole diameter) – (Piston pin
diameter)

If clearance exceeds specification, replace either or both of pis-
ton/piston pin assembly and connecting rod assembly with refer-
ence to specification of each part.

Refer to piston selection table to replace piston/piston pin
assembly. Refer to EM-83, "
HOW TO SELECT PISTON" .

Refer to connecting rod bearing selection table to replace con-
necting rod. Refer to EM-84, "
HOW TO SELECT CONNECTING
ROD BEARING" .
NOTE:
The connecting rod small end grade and piston pin hole (piston
pin) grade are provided only for the parts installed at the plant.
For service parts, no grades can be selected. (Only 0 grade is
available.)

Refer to EM-92, "Connecting Rod Bushing Oil Clearance (Small
End)" for the values for each grade at the plant.
PISTON RING SIDE CLEARANCE

Measure side clearance of piston ring and piston ring groove
using suitable tool.

If out of specification, replace piston and/or piston ring assembly.
PISTON RING END GAP

Check if diameter of cylinder bore is within specification.
Refer to EM-94, "
Piston to Cylinder Bore Clearance" .

Insert piston ring until middle of cylinder with piston, and mea-
sure gap.Standard : 0.002 - 0.006 mm (0.0001 - 0.0002 in)
KBIA2496E
KBIA2536E
Standard:
Top ring : 0.035 - 0.085 mm (0.0014 - 0.0033 in)
2nd ring : 0.030 - 0.070 mm (0.0012 - 0.0028 in)
Oil ring : 0.015 - 0.050 mm (0.0006 - 0.0020 in)
Limit:
Top ring : 0.11 mm (0.0043 in)
2nd ring : 0.10 mm (0.0039 in)
SEM 02 4AA
Standard:
Top ring : 0.23 - 0.33 mm (0.0091 - 0.0130 in)
2nd ring : 0.25 - 0.40 mm (0.0098 - 0.0157 in)
Oil ring : 0.20 - 0.60 mm (0.0079 - 0.0236 in)
Limit:
Top ring : 0.56 mm (0.0220 in)
2nd ring : 0.52 mm (0.0205 in)
Oil ring : 0.96 mm (0.0378 in)
PBIC0 118 E