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Nissan Altima L32. Manual - part 638

EM-88

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

CYLINDER BLOCK

• Install the main bearing caps with the main bearings removed and

tighten the bolts to the specified torque. Refer to

EM-76, "Disas-

sembly and Assembly"

• Using a bore gauge, measure the inner diameter of the main bear-

ing housing.

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

block assembly.

NOTE:

These components cannot be replaced as a single unit because

they were processed together.

PISTON TO CYLINDER BORE CLEARANCE

Inner Diameter of Cylinder Bore

• Using a bore gauge, measure cylinder bore for wear, out-of-round

and taper at 6 different points on each cylinder. (X and Y directions

at A, B and C). The Y axis is in the longitudinal direction of the

engine.

NOTE:

When determining cylinder bore grade, measure cylinder bore at B

position. Refer to

EM-99, "Standard and Limit"

• If there are scratches and/or seizure on the cylinder inner wall,

hone the inner wall.

Outer Diameter of Piston

• Measure piston skirt diameter using a micrometer. Refer to

EM-99,

"Standard and Limit"

• Measure point (distance from the top): 37.5 mm (1.476 in)

Piston to Cylinder Bore Clearance

• Calculate by outer diameter of piston skirt and inner diameter of cylinder (direction X, position B).

(Clearance) = (Inner diameter of cylinder) – (Outer diameter of piston skirt).

• If it 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”.

Standard

: 58.944 - 58.968 mm (2.3206 - 2.3216 in)

PBIC0269E

SBIA0284E

PBIC0125E

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

D: Bored diameter
A: Piston diameter as measured
B: Piston-to-bore clearance (standard value)
C: Honing allowance 0.02 mm (0.0008 in)

CYLINDER BLOCK

EM-89

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

2. Install lower cylinder block, and tighten to the specified torque. Otherwise, cylinder bores may be distorted

in final assembly.

3. Cut cylinder bores.
• 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.
• Measurement should be done after cylinder bore cools down.

OUTER DIAMETER OF CRANKSHAFT JOURNAL

• Measure outer diameter of crankshaft journals.

OUTER DIAMETER OF CRANKSHAFT PIN

• Measure outer diameter of crankshaft pin.

OUT-OF-ROUND AND TAPER OF CRANKSHAFT

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

journal and pin using 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).

CRANKSHAFT RUNOUT

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

both ends of the crankshaft.

• Place a dial gauge straight up on the No. 3 journal.

• While rotating the crankshaft, read the movement of the pointer on

the dial gauge, the total indicator runout reading.

OIL CLEARANCE OF CONNECTING ROD BEARING

Method of Measurement

Standard

: 54.955 - 54.979 mm (2.1636 - 2.1645 in)

Standard

: 44.956 - 44.974 mm (1.7699 - 1.7706 in)

PBIC0270E

Standard
Out-of-round (X - Y)

: 0.005 mm (0.0002 in)

Taper (A - B)

: 0.005 mm (0.0002 in)

PBIC0128E

Limit

: Less than 0.05 mm (0.002 in)

PBIC0271E

EM-90

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

CYLINDER BLOCK

• Install the connecting rod bearings to the connecting rod and the

cap, and tighten the connecting rod bolts to the specified torque.

Using a inside micrometer measure the inner diameter of connect-

ing rod bearing.

(Oil clearance) = (Inner diameter of connecting rod bearing) –

(Outer diameter of crankshaft pin)

• If clearance cannot be adjusted within the standard, grind crank-

shaft pin and use undersized bearing. Refer to

EM-93, "How to

Select Piston and Bearing"

Method of Using Plastigage

• Remove oil and dust on the crankshaft pin and the surfaces of

each bearing completely.

• Cut the 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 cap, and

tighten the connecting rod bolts to the specified torque.

CAUTION:

Never rotate the crankshaft.

• Remove the connecting rod cap and bearings, and using the scale

on the Plastigage bag, measure the Plastigage width.

NOTE:

The procedure when the measured value exceeds the limit is

same as that described in the method by calculation.

OIL CLEARANCE OF MAIN BEARING

Method of Measurement

• Install the main bearings to the cylinder block and bearing cap. Measure the main bearing inner diameter

with the bearing cap bolt tightened to the specified torque.

(Oil clearance) = (Inner diameter of main bearing) – (Outer diameter of crankshaft journal)

• If the measured value exceeds the limit, select main bearings referring to the main bearing inner diameter

and crankshaft journal outer diameter, so that the oil clearance satisfies the standard. Refer to

EM-93, "How

to Select Piston and Bearing"

Method of Using Plastigage

• Remove oil and dust on the crankshaft journal and the surfaces of

each bearing completely.

• Cut the Plastigage slightly shorter than the bearing width, and

place it in crankshaft axial direction, avoiding oil holes.

• 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 limit is

same as that described in the "Method by Calculation".

CRUSH HEIGHT OF MAIN BEARING

Standard

: 0.035 - 0.045 mm (0.0014 - 0.0018 in)

Limit

: 0.10 mm (0.0039 in)

PBIC0119E

EM142

Standard:
No. 1, 3, and 5 journals

: 0.012 - 0.022 mm (0.0005 - 0.0009 in)

No. 2 and 4 journals

: 0.018 - 0.028 mm (0.0007 - 0.0011 in)

Limit

: 0.1 mm (0.004 in)

EM142

CYLINDER BLOCK

EM-91

< DISASSEMBLY AND ASSEMBLY >

[QR25DE]

• When the bearing cap is removed after being tightened to the

specified torque with main bearings installed, the tip end of bearing

must protrude.

• If the standard is not met, replace main bearings.

OUTER DIAMETER OF LOWER CYLINDER BLOCK BOLT

• Perform only with M10 (0.39 in) bolts.

• Measure outer diameters (d1, d2) at two positions as shown.

• Measure d2 at a point within area (A) as shown.

• When the value of d1- d2 exceeds the limit (a large difference in

dimensions), replace the bolt with a new one.

OUTER DIAMETER OF CONNECTING ROD BOLT

• Measure outer diameter (d) at position as shown.

• When (d) exceeds the limit (when it becomes thinner), replace the

bolt with a new one.

MOVEMENT AMOUNT OF FLYWHEEL (M/T MODEL)

NOTE:

• Inspection for double mass flywheel only.

• Do not disassemble double mass flywheel.

Flywheel Deflection

• Measure deflection of flywheel contact surface to the clutch with a

dial gauge.

• Measure runout at 210 mm (8.27 in) dia.

• Measure axial displacement at 250 mm (9.84 in) dia.

• When measured value exceeds the limit, replace the flywheel with

a new one.

Movement Amount in Rotation Direction

• Check the movement amount in the following procedure.

Standard

: There must be crush height.

SEM502G

Limit

: 0.13 mm (0.0051 in)

PBIC0272E

Limit

: 7.75 mm (0.3051 in) or less

PBIC0273E

Limit

: 0.45 mm (0.0177 in) or less under no
load

Limit

: 1.3 mm (0.051 in) or less under 100N
(22.48 lb) force

SBIA0287E

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