2009 INFINITI QX56 engine

EM-92
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
(Piston pin clearance) = (Piston pin hole diameter) – (Piston pin
diameter)
• If clearance exceeds specification, replace either or both the pis-
ton/piston pin assembly and the connecting rod assembly with ref-
erence to the specification of each part.
• Use the piston selection table to replace piston/piston pin assem-
bly. Refer to EM-101, "
How to Select Piston and Bearing".
• Use the connecting rod bearing selection table to replace connect- ing rod. Refer to EM-101, "
How to Select Piston and 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 avail-
able).
• Follow "Connecting Rod Bushing Oil Clearance (Small End)" for the values for each grade at the plant.
PISTON RING SIDE CLEARANCE
• Measure side clearance of the piston ring and piston ring grooveusing suitable tool.
• If out of specification, replac e piston and/or piston ring assembly.
PISTON RING END GAP
• Check if the diameter of the cyli nder bore is within specification.
Refer to EM-108, "
Standard and Limit".
• Insert the piston ring into the middle of the cylinder using the pis- ton, and measure the gap.
• If out of specification, replace piston ring. 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 - 0.185 mm (0.0006 - 0.0073 in)
Limit: Top ring : 0.11 mm (0.0043 in)
2nd ring : 0.10 mm (0.0039 in)
SEM024AA
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)
PBIC0118E
Revision: December 20092009 QX56

ENGINE UNITEM-93
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CONNECTING ROD BEND AND TORSION
• Check connecting rod alignment using suitable tool.
• If measurement exceeds the limi
t, replace connecting rod assem-
bly.
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-83, "
Disassembly and Assembly".
• If measurement exceeds the standard, replace connecting rod.
CONNECTING ROD BUSHING OIL CLEARANCE (SMALL END)
Connecting Rod Inside Diameter (Small End)
• Measure inside diameter of bushing using suitable tool.
Piston Pin Diameter
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
SEM003F
SEM038F
Standard : 57.000 - 57.013 mm (2.2441 - 2.2446 in)
PBIC1641E
Standard : 22.000 - 22.006 mm (0.8661 - 0.8664 in)
PBIC0120E
Revision: December 20092009 QX56

EM-94
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
• 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 measured value exceeds the standard, replace the connectingrod assembly and/or piston and piston pin assembly.
• If replacing the piston and piston pin assembly, use 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-101, "
How to Select Piston and Bearing".
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 en ter the oil or coolant passages.
• Measure block upper face for distortion in six directions as shown.
• If measurement exceeds the limit, replace cylinder block.
MAIN BEARING HOUSING INSIDE DIAMETER
Standard : 21.989 - 21.995 mm (0.8657 - 0.8659 in)
PBIC0117E
Standard : 0.005 - 0.017 mm (0.0002 - 0.0007 in)
KBIA2536E
Grade 0
Connecting rod bushing inside diameter 22.000 - 22.006
(0.8661 - 0.8664)
Piston pin diameter 21.989 - 21.995
(0.8657 - 0.8659)
Piston pin hole diameter 21.993 - 21.999
(0.8659 - 0.8661)
KBIA2496E
Standard : 0.03 mm (0.0012 in)
Limit : 0.1 mm (0.004 in)
SEM123C
Revision: December 20092009 QX56

ENGINE UNITEM-95
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• Install the main bearing caps with the main bearings removed, and
tighten the bolts to the specified torque. Refer to EM-83, "
Disas-
sembly and Assembly".
• Measure inside diameter of main bearing housing.
• If out of the standard, replace cylinder block and main bearing 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 the cylinder bore for wear, out-of-round and taper at six
different 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 measured value exceeds the repair limit, or if ther e are scratches and/or seizure on the cylinder inner wall,
hone or bore the inner wall.
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)
PBIC0124E
Standard : 97. 980 - 98. 010 mm (3.8575 - 3.8587 in)
PBIC0125E
Revision: December 20092009 QX56

EM-96
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
• Measure point ″H″.
Piston to Cylinde r Bore Clearance
• Calculate by using diameter of the piston skirt and the 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 pi ston-to-bore clearance to piston diameter “A”.
2. Install main bearing caps, and tighten them to the specified torque. Otherwise, cylinder bores may be dis-
torted in final assembly.
3. Cut the 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 one time. Cut only 0.05 mm (0.0020 in) or so in diameter at atime.
4. Hone cylinders to obtain the 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 bearing.
CRANKSHAFT PIN DIAMETER
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)
Revision: December 20092009 QX56

ENGINE UNITEM-97
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• Measure diameter of crankshaft pin using suitable tool.
• If measurement is out of standard, measure connecting rod bear-
ing oil clearance. Then use undersize bearing.
OUT-OF-ROUND AND TAPER OF CRANKSHAFT
• Measure dimensions at four di fferent points as 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 measured value exceeds the standard, correct or replace crankshaft.
• If corrected, measure the bearing oil clearance of the corrected journal or pin. Then select the main bearing or connecting rod bearing.
CRANKSHAFT RUNOUT
• Place a V-block on a precise flat table to support the journals onboth ends of the crankshaft.
• Measure at No. 3 journal using suitable tool.
• While rotating crankshaft, read the movement of the pointer.
• Half of the movement shows the runout.
• If measurement exceeds the limit, replace crankshaft.
CONNECTING ROD BEARING OIL CLEARANCE
Method of Measurement
• Install connecting rod bearings to the connecting rod and cap. Tighten connecting rod bolts to the specified
torque. Refer to EM-83, "
Disassembly and Assembly".
Measure inside diameter of connecting rod bearing.
(Oil clearance) = (Inside diameter of connecting rod bearing) –
(Crankshaft pin diameter)
• If clearance cannot be adjusted wit hin the standard, grind crank-
shaft pin and use undersized bearing. Refer to EM-101, "
How to
Select Piston and Bearing".
Method of Using Plastigage
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
Standard : 0.020 - 0.039 mm (0.0008 - 0.0015 in)
Limit : 0.055 mm (0.0022 in)
PBIC1642E
Revision: December 20092009 QX56

EM-98
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
• Remove oil and dust on the crankshaft pin and surfaces of eachbearing completely.
• Cut a plastigage slightly shorter than the bearing width, and place
it in the crankshaft axial direction, avoiding oil holes.
• Install the connecting rod beari ngs to the connecting rod and con-
necting rod bearing cap, and tighten the connecting rod bolts to the
specified torque.
CAUTION:
Do not rotate crankshaft with plastigage installed.
• Remove the connecting rod bear ing cap and bearings. Measure
the plastigage width using the scale on the plastigage bag.
NOTE:
The procedure when the measured value exceeds the repair limit is the 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 bolts tightened to the specified torque. Refer to EM-83, "
Disas-
sembly and Assembly".
(Oil clearance) = (Inside diameter of main bearing) – (Crankshaft
journal diameter)
• If measured value exceeds the repair limit, select main bearings referring to the main bearing inside diame-
ter and crankshaft journal diameter, so that the oil clearance satisfies the standard. Refer to EM-101, "
How
to Select Piston and Bearing".
Method of Using Plastigage
• Remove oil and dust on the crankshaft journal and 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:
Do not rotate crankshaft with plastigage installed.
• Remove bearing cap and bearings. Measure plastigage width using the scale on the plastigage bag.
NOTE:
The procedure when the measured value exceeds the repair limit
is the same as that descri bed in “Method of Measurement”.
CRUSH HEIGHT OF MAIN BEARING
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
KBIA2551E
Revision: December 20092009 QX56

ENGINE UNITEM-99
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• When the bearing cap is removed after being tightened to the
specified torque with main bearings installed, the tip end of the
bearing must protrude. Refer to EM-83, "
Disassembly and Assem-
bly" for the tightening procedure.
• If standard is not met, replace main bearings.
CRUSH HEIGHT OF CONNECTING ROD BEARING
• When connecting rod bearing cap is removed after being tightened to the specified torque with the connecting rod bearings installed,
the tip end of the bearing must protrude. Refer to EM-83, "
Disas-
sembly and Assembly" for tightening procedure.
• If 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 tip of the bolt to dimension "a".
• Measure bolt diameter ″d2″ from the dimension between tip of the
bolt and dimension ″b ″ as base station to dimension ″c″ .
NOTE:
If a narrower part in the threads is determined by visual check,
measure ″d2″ at that point.
• Calculate the difference between ″d1″ and ″d2″ .
M9 bolt
M12 bolt
• Replace applicable bolts if outside the limit.
CONNECTING ROD BOLT DIAMETER
• Measure diameter ″d ″ at position shown.
Standard : There must be crush height
SEM502G
Standard : There must be crush height.
PBIC1646E
KBIA2497E
Dimension “a” : 9 mm (0.35 in)
Dimension “b” : 15 mm (0.59 in)
Dimension “c” : 20 mm (0.79 in)
Limit : 0.15 mm (0.0059 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)
Revision: December 20092009 QX56