2008 INFINITI QX56 engine

ENGINE UNITEM-87
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6. Install main bearing caps.
• Align the identification number to the journal position to install.
• Install it with the front mark (indicated by the arrow) facing thefront of engine.
• Tap caps lightly to seat them in the installation position.
7. Follow the steps below to tighten each main bearing cap bolt.
a. Apply engine oil to threads and seating surfaces of bolts, and tighten all bolts temporarily.
b. Measure tightening angle using Tool. CAUTION:
Measure tightening angle usin g Tool. Do not measure visu-
ally.
• Rotate crankshaft by hand after bolts are tightened. Check if it rotates smoothly.
• Check crankshaft side clearance. Refer to EM-90, "
Inspection After Disassembly".
8. Install rear oil seal to rear oil seal retainer. CAUTION:
Do not damage or scratch ou ter circumference of oil seal.
• Install new rear oil seal in the direction shown.
KBIA2533E
Main bearing cap bolts in
order of 1 to 10 : 39.2 N·m (4.0 kg-m, 29 ft.-lb)
Main bearing cap sub
bolts in order of 11 to 20 : 29.4 N·m (3.0 kg-m, 22 ft-lb)
PBIC0090E
Tool number : KV10112100 (BT-8653-A)
Main bearing cap bolts in
order of 1 to 10 : 40
°
Main bearing cap sub bolts
in order of 11 to 20 : 30
°
Side bolts in order of 21 to
30 : 49 N·m (5.0 kg-m, 36 ft-lb)
WBIA0597E
SEM715A
Revision: March 2010
2008 QX56

EM-88
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
• Tap until flattened with the front edge of the rear oil sealretainer using suitable tool.
• Fit the rear oil seal until it is level with the rear end surface of
rear oil seal retainer.
9. Install rear oil seal retainer. • Apply liquid gasket thoroughly to rear oil seal retainer as
shown.
Use Genuine RTV Silicone Seal ant or equivalent. Refer to
GI-15, "
Recommended Chemical Products and Sealants".
• Apply new engine oil on the lips of rear oil seal. Do not touch.
10. Install the piston to the connecting rod.
a. Install the snap ring to the gr ooves of the piston rear side.
• Insert it fully into the groove to install.
b. Install the piston to the connecting rod. • Heat piston until piston pin can be pushed in by hand without excess force [approx. 60° to 70 C ° (140° to
158 °F)]. From the front to the rear, insert t he piston pin into the piston and the connecting rod.
• Assemble so that the front mark on the piston crown and the
oil holes and cylinder No. on the connecting rod are positioned
as shown.
c. Install the snap ring to the gr ooves of the piston front side.
• Insert it fully into the groove to install.
• After installing, make sure connecting rod moves smoothly.
11. Install piston rings. CAUTION:
Do not damage piston.
• Position each ring with the gap as shown, referring to the pis-ton front mark.
• Install the second ring with the stamped surface facing
upward.
PBIC0097E
SBIA0391E
KBIA2534E
Stamped mark Second ring : 2N
PBIC0100E
Revision: March 2010 2008 QX56

ENGINE UNITEM-89
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12. Install the connecting rod bearings to the connecting rod and
connecting rod cap.
• When installing the connecting rod bearings, apply engine oilto the bearing surface (inside). Do not apply oil to the back
surface, but thoroughly clean it.
• When installing, align the connecting rod bearing stopper pro-
trusion with the cutout of the connecting rod to install.
• Check that the oil holes on the connecting rod and those on the corresponding bearing are aligned.
13. Install the piston and connecting rod assembly to the crankshaft using Tool.
• Position the crankshaft pin corresponding to the connecting
rod to be installed onto bottom dead center.
• Apply engine oil sufficiently to the cylinder bore, piston, and
crankshaft pin.
• Match the cylinder position with the cylinder No. on the con- necting rod to install.
• Install the piston with the front mark on the piston crown facing the front of the engine.
CAUTION:
Be careful not to damage the crankshaft pin, resu lting from an interference of the connecting rod
big end.
14. Install connecting rod cap. • Match the stamped cylinder number marks on the connectingrod with those on the cylinder cap to install.
15. Tighten connecting rod bolts using Tool. • Apply engine oil to threads and seats of connecting rod bolts.
• After tightening bolts, make sure the crankshaft rotatessmoothly.
• Check connecting rod side clearance. Refer to EM-90,
"Inspection After Disassembly".
PBIC0266E
Tool number : EM03470000 (J-8037)
WBIA0626E
KBIA2536E
Tool number : KV10112100 (BT-8653-A)
Connecting rod bolts
Step 1 : 19.6 N·m (1.5 kg-m, 11 ft-lb)
Step 2: 90° clockwise
WBIA0627E
Revision: March 2010 2008 QX56

EM-90
< DISASSEMBLY AND ASSEMBLY >
ENGINE UNIT
16. Install knock sensors.CAUTION:
If knock sensor is dropped, replace it with a new one.
• Make sure that there is no foreign material on the cylinderblock mating surface and the back surface of knock sensor.
• Install it with its connector facing the center of the cylinder
block side.
• Do not tighten knock sensor bolts while holding connector.
• Make sure knock sensor does not interfere with other parts.
• Position the sub-harness as shown before installing intake manifold.
17. Installation of the remaining components is in the reverse order of removal.
18. Remove engine assembly from engine stand.
19. Install drive plate. • Align dowel pin of crankshaft rear end with pin holes of eachpart to install.
• Install drive plate, reinforcement plate and pilot converter (if not installed in step 4) as shown.
• Face the chamfered or rounded edge side to the crankshaft.
Inspection After DisassemblyINFOID:0000000001538833
CRANKSHAFT END PLAY
KBIA2493E
KBIA2549E
KBIA2494E
KBIA2537E
Revision: March 2010 2008 QX56

ENGINE UNITEM-91
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• Move the crankshaft fully forward and backward and measure the
clearance between the thrust bear ings and crankshaft arm using
suitable tool.
• If measured value exceeds the repair limit, replace the thrust bear- ings, and measure again. If it still exceeds the repair limit, replace
crankshaft also.
CONNECTING ROD SIDE CLEARANCE
• Measure side clearance between the connecting rod and crank-shaft arm using suitable tool.
• If measured value exceeds the repair limit, replace the connecting rod bearings, and measure again. If it still exceeds the repair limit,
replace the crankshaft also.
PISTON AND PISTON PIN CLEARANCE
Piston Pin Hole Diameter
• Measure diameter of piston pin hole using suitable tool.
Piston Pin Diameter
• Measure diameter of piston pin using suitable tool.
Piston and Piston Pin Clearance
Standard : 0.10 - 0.26 mm (0.0039 - 0.0102 in)
Limit : 0.30 mm (0.0118 in)
PBIC0114E
Standard : 0.20 - 0.40 mm (0.0079 - 0.0157 in)
Limit : 0.40 mm (0.0157 in)
PBIC0115E
Standard : 21.993 - 21.999 mm (0.8659 - 0.8661 in)
PBIC0116E
Standard : 21.989 - 21.995 mm (0.8657 - 0.8659 in)
PBIC0117E
Revision: March 2010 2008 QX56

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 the "Connecting Rod Bushing Oil Clearance (Small End)" procedure 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.
Follow the "Piston to Cylinder Bore Clearance" procedure.
• Insert the piston ring into the middle of the cylinder using the pis- ton, and measure the gap.
• If out of specification, replace pi ston ring. If the gap still exceeds the li mit even with a new ring, re-bore the
cylinder and use oversized piston and 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 - 0.050 mm (0.0006 - 0.0020 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: March 2010 2008 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-82, "
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: March 2010 2008 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: March 2010 2008 QX56