2004 INFINITI QX56 Meter

CYLINDER BLOCK
EM-91
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Revision: August 20072004 QX56

If out of specification, replace piston ring. If gap still exceeds the limit even with a new ring, re-bore cylin-
der and use oversized piston and piston ring.
CONNECTING ROD BEND AND TORSION

Check the connecting rod alignment using suitable tool.

If measurement exceeds the limit, replace connecting rod
assembly.
CONNECTING ROD BEARING (BIG END)

Install the connecting rod cap without the connecting rod bearing
installed. After tightening the connecting rod bolt to the specified
torque, measure the connecting rod large end inside diameter.
Refer to EM-77, "
ASSEMBLY" .

If measurement exceeds the standard, replace the connecting
rod.
CONNECTING ROD BUSHING OIL CLEARANCE (SMALL END)
Connecting Rod Inside Diameter (Small End)

Measure inside diameter of bushing using suitable tool.Limit:
Bend
: 0.15 mm (0.0059 in) per 100 mm (3.94 in) length
To r s i o n
: 0.30 mm (0.0118 in) per 100 mm (3.94 in) length
SEM 00 3F
SEM 03 8F
Standard : 57.000 - 57.013 mm (2.2441 - 2.2446 in)
PBIC1641E
Standard : 22.000 - 22.006 mm (0.8661 - 0.8664 in)
PBIC0120E

EM-92Revision: August 2007
CYLINDER BLOCK
2004 QX56
Piston Pin Diameter

Measure diameter of piston pin using suitable tool.
Connecting Rod Bushing Oil Clearance (Small End)
(Connecting rod small end oil clearance) = (Inside diameter of con-
necting rod small end) – (Piston pin diameter)

If the measured value exceeds the standard, replace the con-
necting rod assembly and/or piston and piston pin assembly.

If replacing the piston and piston pin assembly, refer to the Table
for Selective Fitting for Piston to select the piston corresponding
to the applicable bore grade of the cylinder block to be used.
Refer to EM-83, "
HOW TO SELECT PISTON" .
Factory installed parts grading:

Only grade 0 is available.
Unit: mm (in)
CYLINDER BLOCK DISTORTION

Remove any oil, scale, gasket, sealant and carbon deposits from the cylinder block surface.
CAUTION:
Do not allow any debris to enter the oil or coolant passages.

Measure the block upper face for distortion in six directions as
shown.

If measurement exceeds the limit, replace the cylinder block.Standard : 21.989 - 21.995 mm (0.8657 - 0.8659 in)
PBIC0 117 E
Standard : 0.005 - 0.017 mm (0.0002 - 0.0007 in)
KBIA2536E
Grade 0
Connecting rod bushing inside diameter22.000 - 22.006
(0.8661 - 0.8664)
Piston pin diameter21.989 - 21.995
(0.8657 - 0.8659)
Piston pin hole diameter21.993 - 21.999
(0.8659 - 0.8661)
KBIA2496E
Standard : 0.03 mm (0.0012 in)
Limit : 0.1 mm (0.004 in)
SEM 12 3C

CYLINDER BLOCK
EM-93
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Revision: August 20072004 QX56
MAIN BEARING HOUSING INSIDE DIAMETER

Install the main bearing caps with the main bearings removed,
and tighten the bolts to the specified torque. Refer to EM-77,
"ASSEMBLY" .

Measure the inside diameter of the main bearing housing.

If out of the standard, replace the cylinder block and main bear-
ing caps as an assembly.
NOTE:
These components must be replaced as a single unit, because
they were processed together.
PISTON TO CYLINDER BORE CLEARANCE
Cylinder Bore Diameter

Measure cylinder bore for wear, out-of-round and taper at six dif-
ferent points on each cylinder ("X" and "Y" directions at "A", "B"
and "C").
NOTE:
When determining cylinder bore grade, measure cylinder bore at
B position.

If the measured value exceeds the repair limit, or if there are
scratches and/or seizure on the cylinder inner wall, hone or bore the inner wall.

An oversize piston is provided. When using an oversize piston, hone the cylinder so that the clearance
between the piston and cylinder satisfies the standard.

If oversize piston is used, use it for all cylinders with oversize piston rings.
Piston Skirt Diameter

Measure piston skirt diameter using suitable tool.Standard : 68.944 - 68.968 mm (2.7143 - 2.7153 in)
PBIC1643E
PBIC0123E
Standard diameter:
98.000 - 98.030 mm (3.8583 - 3.8594 in)
Wear limit:
0.20 mm (0.0079 in)
Out-of-round (Difference between X and Y):
Limit: 0.015 mm (0.0006 in)
Taper limit (Difference between A and C):
Limit: 0.010 mm (0.0004 in)
Piston oversize Grade No. 0 (Service) : 0.20 mm (0.0079 in)
PBIC0124E
Standard : 97. 980 - 98. 010 mm (3.8575 - 3.8587 in)
PBIC0125E

EM-94Revision: August 2007
CYLINDER BLOCK
2004 QX56

Measure point “H”.
Piston to Cylinder Bore Clearance

Calculate by using diameter of piston skirt and cylinder bore diameter (direction X, position B).
(Clearance) = (Cylinder bore diameter) – (piston skirt diameter)

If calculation exceeds the limit, replace piston/piston pin assembly.
Reboring Cylinder Bore
1. Cylinder bore size is determined by adding piston-to-bore clearance to piston diameter “A”.
2. Install main bearing caps, and tighten to the specified torque. Otherwise, cylinder bores may be distorted
in final assembly.
3. Cut cylinder bores.
NOTE:

When any cylinder needs boring, all other cylinders must also be bored.

Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 in) or so in diameter at a
time.
4. Hone cylinders to obtain specified piston-to-bore clearance.
5. Measure finished cylinder bore for out-of-round and taper.
NOTE:
Measurement should be done after cylinder bore cools down.
CRANKSHAFT JOURNAL DIAMETER

Measure diameter of crankshaft journals.

If measurement is out of standard, measure the main bearing oil clearance. Then use the undersize bear-
ing. Refer to EM-96, "
MAIN BEARING OIL CLEARANCE" . Distance from the top : 39 mm (1.54 in)
KBIA2545E
Standard : 0.010 - 0.030 mm (0.0004 - 0.0012 in)
Limit : 0.08 mm (0.0031 in)
Rebored size calculation: D = A +B - C
where,
D: Bored diameter
A: Piston diameter as measured
B: Piston - to - bore clearance (standard value)
C: Honing allowance 0.02 mm (0.0008 in)
Standard : 63.940 - 63.964 mm (2.5173 - 2.5183 in)

CYLINDER BLOCK
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Revision: August 20072004 QX56
CRANKSHAFT PIN DIAMETER

Measure diameter of crankshaft pin using suitable tool.

If measurement is out of standard, measure the connecting rod
bearing oil clearance. Then use the undersize bearing. Refer to
EM-95, "
CONNECTING ROD BEARING OIL CLEARANCE" .
OUT-OF-ROUND AND TAPER OF CRANKSHAFT

Measure the dimensions at four different points shown on each
journal and pin.

Out-of-roundness is indicated by the difference in dimension
between "X" and "Y" at "A" and "B".

Taper is indicated by the difference in dimension between "A"
and "B" at "X" and "Y".

If the measured value exceeds the standard, correct or replace the crankshaft.

If corrected, measure the bearing oil clearance of the corrected journal or pin. Then select the main bear-
ing or connecting rod bearing. Refer to EM-96, "
MAIN BEARING OIL CLEARANCE" or EM-95, "CON-
NECTING ROD BEARING OIL CLEARANCE" .
CRANKSHAFT RUNOUT

Place a V-block on a precise flat table to support the journals on
both ends of the crankshaft.

Measure at the No. 3 journal.

While rotating the crankshaft, read the movement of the pointer
on the dial gauge.

Half of the movement shows the runout.

If measurement exceeds the limit, replace the crankshaft.
CONNECTING ROD BEARING OIL CLEARANCE
Method of Measurement

Install the connecting rod bearings to the connecting rod and the cap, and tighten the connecting rod bolt
to the specified torque. Refer to EM-77, "
ASSEMBLY" . Standard : 53.956 - 53.974 mm (2.1243 - 2.1250 in)
PBIC0127E
Limit
Out-of-round (Difference between X and Y)
: 0.002 mm (0.0001 in)
Taper (Difference between A and B)
: 0.002 mm (0.0001 in)
PBIC1685E
Limit : Less than 0.05 mm (0.002 in)
PBIC0129E

EM-96Revision: August 2007
CYLINDER BLOCK
2004 QX56
Measure the inside diameter of connecting rod bearing.
(Oil clearance) = (Inside diameter of connecting rod bearing) –
(Crankshaft pin diameter)

If clearance cannot be adjusted within the standard, grind crank-
shaft pin and use undersized bearing. Refer to EM-85, "
HOW
TO SELECT MAIN BEARING" .
Method of Using Plastigage

Remove oil and dust on the crankshaft pin and the surfaces of
each bearing completely.

Cut a plastigage slightly shorter than the bearing width, and
place it in crankshaft axial direction, avoiding oil holes.

Install the connecting rod bearings to the connecting rod and
connecting rod bearing cap, and tighten the connecting rod bolt
to the specified torque.
CAUTION:
Never rotate the crankshaft.

Remove the connecting rod bearing cap and bearings, and
using the scale on the plastigage bag, measure the plastigage
width.
NOTE:
The procedure when the measured value exceeds the repair limit is same as that described in “Method of
Measurement.”
MAIN BEARING OIL CLEARANCE
Method of Measurement

Install the main bearings to the cylinder block and main bearing
cap. Measure the main bearing inside diameter with the bearing
cap bolt tightened to the specified torque. Refer to EM-77,
"ASSEMBLY" .
(Oil clearance) = (Inside diameter of main bearing) – (Crank-
shaft journal diameter)

If the measured value exceeds the repair limit, select main bearings referring to the main bearing inside
diameter and crankshaft journal diameter, so that the oil clearance satisfies the standard. Refer to EM-85
.Standard : 0.020 - 0.039 mm (0.0008 - 0.0015 in)
Limit : 0.055 mm (0.0022 in)
PBIC1642E
KBIA2550E
Standard:
No. 1 and 5 journals
: 0.001 - 0.011 mm (0.00004 - 0.0004 in)
No. 2, 3 and 4 journals
: 0.007 - 0.017 mm (0.0003 - 0.0007 in)
Limit:
No.1 and 5 journals
: 0.021 mm (0.0008 in)
No. 2, 3 and 4 journals
: 0.027 mm (0.0011 in)
PBIC1644E

CYLINDER BLOCK
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Revision: August 20072004 QX56
Method of Using Plastigage

Remove oil and dust on the crankshaft journal and the surfaces
of each bearing completely.

Cut a plastigage slightly shorter than the bearing width, and
place it in crankshaft axial direction, avoiding oil holes.

Install the main bearings to the cylinder block and main bearing
cap, and tighten the main bearing bolts to the specified torque.
CAUTION:
Never rotate the crankshaft.

Remove the bearing cap and bearings, and using the scale on
the plastigage bag, measure the plastigage width.
NOTE:
The procedure when the measured value exceeds the repair limit is same as that described in “Method of
Measurement”.
CRUSH HEIGHT OF MAIN BEARING

When the bearing cap is removed after being tightened to the
specified torque with main bearings installed, the tip end of bear-
ing must protrude. Refer to EM-77, "
ASSEMBLY" for the tight-
ening procedure.

If the standard is not met, replace main bearings.
CRUSH HEIGHT OF CONNECTING ROD BEARING

When the connecting rod bearing cap is removed after being
tightened to the specified torque with connecting rod bearings
installed, the tip end of bearing must protrude. Refer to EM-77,
"ASSEMBLY" for the tightening procedure.

If the standard is not met, replace connecting rod bearings.
MAIN BEARING CAP BOLT DIAMETER

Check for bolts (M9 and M12) installed from lower side using the
following procedure.
NOTE:

Side bolt (M10) is outside the target.

Figure shows M12 bolt.

Measure bolt diameter "d1" from the tip of bolt to dimension "a".

Measure bolt diameter "d2" from the dimension between the tip
of bolt and dimension "b" as base station to dimension "c".
NOTE:
Measure "d2" at that point if narrower part in the threads is
determined by visual check.

Calculate the difference between "d1" and "d2".
KBIA2551E
Standard : There must be crush height
SEM 50 2G
Standard : There must be crush height.
PBIC1646E
KBIA2497E

EM-98Revision: August 2007
CYLINDER BLOCK
2004 QX56
M9 bolt
M12 bolt

Replace applicable bolts if outside the limit.
CONNECTING ROD BOLT DIAMETER

Measure diameter "d" at position shown.

When “d” exceeds the limit (when it becomes thinner), replace
the bolt with a new one.Dimension “a” : 9 mm (0.35 in)
Dimension “b” : 15 mm (0.59 in)
Dimension “c” : 20 mm (0.79 in)
Limit : 0.10 mm (0.0039 in)
Dimension “a” : 12 mm (0.47 in)
Dimension “b” : 55 mm (2.17 in)
Dimension “c” : 20 mm (0.79 in)
Limit : 0.15 mm (0.0059 in)
Limit : 7.75 mm (0.3051 in) or less.
SBIA0286E