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Nissan Frontier D40. Manual - part 590

EM-92

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

ENGINE UNIT

Measure the outer diameter of piston pin with a micrometer.

Connecting Rod Bushing Oil Clearance

(Connecting rod bushing oil clearance) = (Connecting rod bushing inner diameter) – (Piston pin outer diame-
ter)

• If the measured value is out of the standard, replace connecting rod assembly and/or piston and piston pin

assembly.

• If replacing piston and piston pin assembly, refer to

EM-106, "Standard and Limit"

• If replacing connecting rod assembly, refer to

EM-106, "Standard

and Limit"

to select connecting rod bearing.

Factory installed parts grading:
• Service parts apply only to grade “0”.

Unit: mm (in)

*: After installing in connecting rod.

CYLINDER BLOCK DISTORTION

• Remove gasket on the cylinder block surface, and also remove engine oil, scale, carbon, or other contami-

nation; using suitable tool.

CAUTION:

Do not allow any debris to enter engine oil or engine coolant passages.

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

PBIC0117E

Standard: 0.005 - 0.017 mm (0.0002 - 0.0007 in)

PBIC2196E

Grade

Connecting rod bushing

inner diameter

20.000 - 20.006
(0.7874 - 0.7876)

20.006 - 20.012
(0.7876 - 0.7879)

Piston pin hole diameter

19.993 - 19.999

(0.7871 - 0.7874)

19.999 - 20. 005
(0.7874 - 0.7876)

Piston pin outer diameter

19.989 - 19.995
(0.7870 - 0.7872)

19.995 - 20.001
(0.7872 - 0.7874)

PBIC3019E

ENGINE UNIT

EM-93

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

• Measure the distortion on the cylinder block upper face at some

different points in six directions with straightedge and feeler gauge.

• If it exceeds the limit, replace cylinder block and lower cylinder

block assembly.
NOTE:
Cylinder block cannot be replaced as a single part, because it is
machined together with lower cylinder block.

MAIN BEARING HOUSING INNER DIAMETER

• Install lower cylinder block without main bearings installed, and

tighten lower cylinder block bolts to the specified torque. Refer to

EM-79, "Disassembly and Assembly"

for the tightening procedure.

• Measure the inner diameter of main bearing housing with a bore

gauge.

• If out of the standard, replace cylinder block and lower cylinder

block assembly.
NOTE:
Cylinder block cannot be replaced as a single part, because it is
machined together with lower cylinder block.

PISTON TO CYLINDER BORE CLEARANCE

Cylinder Bore Inner Diameter

• Using a bore gauge, 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)] [(Y) is in longitudinal direction of the
engine].
NOTE:
When determining cylinder bore grade, measure cylinder bore at
(B) position.

• If the measured value exceeds the limit, or if there are scratches and/or seizure on the cylinder inner wall,

hone or re-bore the cylinder inner wall.

Piston Skirt Diameter

Limit: 0.1 mm (0.004 in)

PBIC0121E

Standard: 58.944 - 58.968 mm (2.3206 - 2.3216 in)

PBIC2012E

Standard inner diameter:

89.010 - 89.030 mm (3.5043 - 3.5051 in)

Wear limit:

0.2 mm (0.008 in)

Out-of-round [Difference between (X) and (Y)]:

0.015 mm (0.0006 in)

Taper limit [Difference between (A) and (C)]:

0.01 mm (0.0004 in)

SBIA0284E

EM-94

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

ENGINE UNIT

Measure the outer diameter of piston skirt with a micrometer.

Piston to Cylinder Bore Clearance

Calculate by piston skirt diameter and cylinder bore inner diameter [direction (X), position (B)].
(Clearance) = (Cylinder bore inner diameter) – (Piston skirt diameter)

• If it exceeds the limit, replace piston and piston pin assembly. Refer to

EM-99, "How to Select Piston and

Bearing"

Re-boring Cylinder Bore

Cylinder bore size is determined by adding piston to cylinder bore clearance to piston skirt diameter.

Install lower cylinder block, and tighten bolts to the specified torque. Otherwise, cylinder bores may be dis-
torted in final assembly. Refer to

EM-79, "Disassembly and Assembly"

for the tightening procedure.

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.

Hone cylinders to obtain the specified piston to cylinder bore clearance.

Measure the finished cylinder bore for out-of-round and taper.
NOTE:
Measurement should be done after cylinder bore cools down.

CRANKSHAFT MAIN JOURNAL DIAMETER

• Measure the outer diameter of crankshaft main journals with a

micrometer.

• If out of the standard, measure the main bearing oil clearance.

Then use undersize bearing. Refer to

EM-106, "Standard and

Limit"

CRANKSHAFT PIN JOURNAL DIAMETER

Measure point

: Distance from the top 42.98 mm (1.692 in)

Standard

: 88.990 - 89.010 mm (3.5035 - 3.5043 in)

PBIC0125E

Standard

: 0.010 - 0.030 mm (0.0004 - 0.0012 in)

Limit

: 0.08 mm (0.0031 in)

Re-bored size calculation: D = A + B - C

where,

D: Bored diameter

A: Piston diameter as measured

B: Piston - to - cylinder bore clearance (standard value)

C: Honing allowance 0.02 mm (0.0008 in)

Standard: 54.955 - 54.979 mm (2.1636 - 2.1645 in) dia.

PBIC0270E

ENGINE UNIT

EM-95

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

• Measure the outer diameter of crankshaft pin journal with a micrometer.

• If out of the standard, measure the connecting rod bearing oil clearance. Then use undersize bearing. Refer

EM-106, "Standard and Limit"

OUT-OF-ROUND AND TAPER OF CRANKSHAFT

• Measure the dimensions at four different points as shown on each

main journal and pin journal with a micrometer.

• Out-of-round is indicated by the difference in dimensions 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 limit, correct or replace crankshaft.
• If corrected, measure the bearing oil clearance of the corrected main journal and/or pin journal. Then select

main bearing and/or connecting rod bearing. Refer to

EM-106, "Standard and Limit"

CRANKSHAFT RUNOUT

• Place a V-block on a precise flat table to support the journals on

the both end of crankshaft.

• Place a dial indicator straight up on the No. 3 journal.
• While rotating crankshaft, read the movement of the pointer on the

dial indicator. (Total indicator reading)

• If it exceeds the limit, replace crankshaft.

CONNECTING ROD BEARING OIL CLEARANCE

Method by Calculation

• Install connecting rod bearings to connecting rod and cap, and tighten connecting rod bolts to the specified

torque. Refer to

EM-79, "Disassembly and Assembly"

for tightening procedure.

• Measure the inner diameter of connecting rod bearing with an

inside micrometer.
(Bearing oil clearance) = (Connecting rod bearing inner diameter)
– (Crankshaft pin journal diameter)

• If the clearance exceeds the limit, select proper connecting rod

bearing according to connecting rod big end diameter and crank-
shaft pin journal diameter to obtain the specified bearing oil clear-
ance. Refer to

EM-99, "How to Select Piston and Bearing"

Method of Using Plastigage

• Remove engine oil and dust on 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 connecting rod bearings to connecting rod and cap, and tighten connecting rod bolts to the specified

torque. Refer to

EM-79, "Disassembly and Assembly"

for the tightening procedure.

Standard: 44.956 - 44.974 mm (1.7699-1.7706 in) dia.

Limit:

Out-of-round [Difference between (X) and (Y)]

: 0.0025 mm (0.0001 in)

Taper [Difference between (A) and (B)]

: 0.0025 mm (0.0001 in)

PBIC2203E

Limit

: 0.05 mm (0.0020 in)

PBIC2541E

Standard

: 0.035 - 0.045 mm (0.0014 - 0.0018 in)

PBIC1642E

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