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Nissan Frontier. Manual - part 725

ENGINE UNIT

EM-89

< UNIT DISASSEMBLY AND ASSEMBLY >

[QR25DE]

b. Install the piston to the connecting rod.

• Using a heat gun, heat the piston [approximately 60

° - 70° C (140° - 158° F)] until the piston pin can be

pushed in by hand without excessive force. From the front to the rear, insert the piston pin into the piston

and the connecting rod.

• Assemble so that the front mark on the piston crown and the

oil holes and the cylinder No. on the connecting rod are posi-

tioned as shown.

c. Install the piston pin snap ring into the front of the piston.

• Check that the connecting rod moves smoothly.

9. Using a piston ring expander, install the piston rings. Assemble

the components in their original positions.

CAUTION:

• When installing piston rings, be careful not to damage

piston.

• Be careful not to damage piston rings by expanding them

excessively.

• Position each ring with the gap as shown, referencing the pis-

ton front mark as the starting point.

• Install the top ring and the second ring with the stamped sur-

face facing upward.

10. Install the connecting rod bearings to the connecting rod and the

connecting rod cap. Assemble the components in their original

positions.

• When installing the connecting rod bearings, apply engine oil

to the bearing friction surface (inside). Do not apply oil to the

back surface, but thoroughly clean the back.

• When installing, align the connecting rod bearing stopper pro-

trusion with the notch of the connecting rod to install.

• Check the oil holes on the connecting rod and those on the

corresponding bearing are aligned.

11. Install the piston and connecting rod assembly to the crankshaft.

Assemble the components in their original positions.

• Rotate the crankshaft so the pin corresponding to the connect-

ing rod to be installed is at the bottom dead center position.

• Apply engine oil sufficiently to the cylinder bore, piston, and

crankshaft pin.

• Match the cylinder position number with the cylinder No. on

the connecting rod for installation.

• Install the piston with the front mark on the piston crown facing

the front of the engine using Tool.

CAUTION:

Be careful not to damage the cylinder wall and crankshaft pin, resulting from an interference of the

connecting rod big end.

PBIC0099E

Stamped mark

: 2ND (second ring)

PBIC0100E

PBIC0266E

Tool number

: EM03470000 (J-8037)

WBIA0620E

EM-90

< UNIT DISASSEMBLY AND ASSEMBLY >

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ENGINE UNIT

12. Install the connecting rod bearing caps. Assemble the compo-

nents in their original positions.

• Match the stamped cylinder number marks on the connecting

rod with those on the cap to install.

13. Tighten the connecting rod bolts using Tool in four steps as fol-

lows:

• Apply engine oil to the threads and seats of the connecting rod

bolts.

CAUTION:

Check tightening angle using Tool. Do not ighten by

visual inspection.

• Check the connecting rod side clearance. Refer to

EM-91, "Inspection After Disassembly"

• After tightening the bolts, make sure that the crankshaft rotates smoothly.

14. Install flywheel (M/T Models), or drive plate (A/T Models).

• Install drive plate, reinforcement plate and pilot converter as

shown.

• Using a drift with 33 mm (1.30 in) diameter, push pilot con-

verter into the end of the crankshaft.

• Press fit pilot bushing into the crankshaft as shown; using a

suitable drift of 19 mm (0.75 in)

15. Install the cylinder block heater (if equipped).

16. Install the knock sensor.

• Make sure that there is no foreign material on the cylinder

block mating surface and the back surface of the knock sen-

sor.

• Install the knock sensor with the connector facing lower left by

° as shown.

• Do not tighten the knock sensor bolt while holding the connec-

tor.

• Make sure that the knock sensor does not interfere with other

components.

SBIA0282E

Tool number

: KV10112100 (BT-8653-A)

Step 1

: 27.4 N·m (2.8 kg-m, 20 ft-lb)

Step 2

: 0 N·m (0 kg-m, 0 ft-lb)

Step 3

: 19.6 N·m (2.0 kg-m, 14 ft-lb)

Step 4

: 90

° - 95° (target 90° degrees)

WBIA0621E

KBIA0075E

Cylinder block heater

: 73.5 N·m (7.5 kg-m, 54 ft-lb)

Knock sensor bolt : 21.1 N·m (2.2 kg-m, 16 ft-lb)

PBIC3020E

ENGINE UNIT

EM-91

< UNIT DISASSEMBLY AND ASSEMBLY >

[QR25DE]

CAUTION:

If the knock sensor is dropped, replace it with new one.

17. Install the crankshaft position sensor (POS).

18. Installation of remaining components is in reverse order of removal.

Inspection After Disassembly

INFOID:0000000009478080

CRANKSHAFT END PLAY

• Measure the clearance between thrust bearings and crankshaft

arm when crankshaft is moved fully forward or backward with a dial

indicator.

• If the measured value exceeds the limit, replace thrust bearings,

and measure again. If it still exceeds the limit, replace crankshaft

also.

CONNECTING ROD SIDE CLEARANCE

• Measure the side clearance between connecting rod and crank-

shaft arm with a feeler gauge.

• If the measured value exceeds the limit, replace connecting rod,

and measure again. If it still exceeds the limit, replace crankshaft

also.

PISTON TO PISTON PIN OIL CLEARANCE

Piston Pin Hole Diameter

Measure the inner diameter of piston pin hole with an inside

micrometer.

Piston Pin Outer Diameter

Crankshaft position
sensor bolt

: 7.0 N·m (0.71 kg-m, 62 in-lb)

Standard

: 0.10 - 0.26 mm (0.0039 - 0.0102 in)

Limit

: 0.30 mm (0.0118 in)

PBIC2377E

Standard

: 0.20 - 0.35 mm (0.0079 - 0.138 in)

Limit

: 0.50 mm (0.0197 in)

KBIA0071E

Standard: 19.993 - 20.005 mm (0.7871 - 0.7876 in)

PBIC0116E

EM-92

< UNIT DISASSEMBLY AND ASSEMBLY >

[QR25DE]

ENGINE UNIT

Measure the outer diameter of piston pin with a micrometer.

Piston to Piston Pin Oil Clearance

(Piston to piston pin oil clearance) = (Piston pin hole diameter) – (Piston pin outer diameter)

• If oil clearance is out of the standard, replace piston and piston pin assembly.

• When replacing piston and piston pin assembly. Refer to

EM-108, "Standard and Limit"

NOTE:

• Piston is available together with piston pin as assembly.

• Piston pin (piston pin hole) grade is provided only for the parts installed at the plant. For service parts, no

grades can be selected. (Only grade “0” is available.)

PISTON RING SIDE CLEARANCE

• Measure the side clearance of piston ring and piston ring groove

with a feeler gauge.

• If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit,

replace piston also.

PISTON RING END GAP

• Make sure that cylinder bore inner diameter is within the specifica-

tion. Refer to

EM-108, "Standard and Limit"

• Lubricate with new engine oil to piston and piston ring, and then

insert piston ring until middle of cylinder with piston, and measure

piston ring end gap with a feeler gauge.

• If the measured value exceeds the limit, replace piston ring, and measure again.

Standard: 19.989 - 20.001 mm (0.7870 - 0.7874 in)

PBIC0117E

Standard: 0.002 - 0.006 mm (0.0001 - 0.0002 in)

Standard:

Top ring

: 0.045 - 0.080 mm (0.0018 - 0.0031 in)

2nd ring

: 0.030 - 0.070 mm (0.0012 - 0.0028 in)

Oil ring

: 0.065 - 0.135 mm (0.0026 - 0.0053 in)

Limit:

Top ring

: 0.11 mm (0.0043 in)

2nd ring

: 0.10 mm (0.0039 in)

SEM024AA

Standard:

Top ring

: 0.21 - 0.31 mm (0.0083 - 0.0122 in)

2nd ring

: 0.32 - 0.47 mm (0.0126 - 0.0185 in)

Oil ring (rail ring) : 0.20 - 0.60 mm (0.0079 - 0.0236 in)

Limit:

Top ring

: 0.54 mm (0.0213 in)

2nd ring

: 0.65 mm (0.0256 in)

Oil ring (rail ring) : 0.95 mm (0.0374 in)

SEM822B

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