Nissan Altima L32. Instruction — part 621

EM-20

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CAMSHAFT VALVE CLEARANCE

CAMSHAFT VALVE CLEARANCE

Camshaft valve clearance

INFOID:0000000004202113

• Perform this inspection as follows after removal, installation, or replacement of the camshaft or any valve-

related parts, or if there are any unusual engine conditions due to changes in valve clearance over time

(starting, idling, and/or noise).

1. Warm up the engine, then stop it.
2. Remove the fender protector side cover RH using power tool. Refer to

EXT-19, "Removal and Installation"

(Coupe models) or

EXT-40, "Removal and Installation"

(Sedan models).

3. Remove the rocker cover using power tool.

Refer to

EM-39, "Removal and Installation"

.

4. Turn crankshaft pulley in normal direction (clockwise when

viewed from front) to align TDC identification mark (without paint

mark) with timing indicator.

5. At this time, check that the both intake and exhaust cam lobes of

No. 1 cylinder face outside.

• If they do not face outside, turn crankshaft pulley once more.

6. Measure valve clearances with a feeler gauge at locations

marked (X) in the table below.

• No.1 cylinder compression TDC.

KBIA0190E

KBIA0400J

Cylinder

No.1

No.2

No.3

No.4

Valve

INT

EXH

INT

EXH

INT

EXH

INT

EXH

Measurable

×

×

×

x

KBIA0248E

CAMSHAFT VALVE CLEARANCE

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• Use a feeler gauge to measure the clearance between valve

and camshaft.

*Approximately 80

°C (176°F)

CAUTION:

If inspection was carried out with cold engine, check that values with fully warmed up engine are

still within specifications.

7. Turn crankshaft one complete revolution (360

°) and align mark on crankshaft pulley with pointer.

8. Measure valve clearances with a feeler gauge at locations

marked (X) in the table below.

• No.4 cylinder compression TDC.

• If out of specifications, make necessary adjustment.

ADJUSTMENT

• Perform adjustment depending on selected head thickness of valve lifter.

• The specified valve lifter thickness is the dimension at normal temperatures. Ignore dimensional differences

caused by temperature. Use the specifications for hot engine condition to adjust.

1. Remove camshaft. Refer to

EM-41, "Removal and Installation"

.

2. Remove the valve lifters at the locations that are outside the standard.
3. Measure the center thickness of the removed valve lifters with a

micrometer.

4. Use the equation below to calculate valve lifter thickness for replacement.

• Valve lifter thickness calculation.

t = t1 + (C1 - C2)

t = Thickness of replacement valve lifter.

t1 = Thickness of removed valve lifter.

C1 = Measured valve clearance.

C2 = Standard valve clearance.

Valve clearance standard:
Cold

Intake

: 0.24 - 0.32 mm (0.009 - 0.013 in)

Exhaust

: 0.26 - 0.34 mm (0.010 - 0.013 in)

Hot*

Intake

: 0.304 - 0.416 mm (0.012 - 0.016 in)

Exhaust

: 0.308 - 0.432 mm (0.012 - 0.017 in)

Cylinder

No.1

No.2

No.3

No.4

Valve

INT

EXH

INT

EXH

INT

EXH

INT

EXH

Measurable

x

×

x

×

KBIA0185E

KBIA0249E

KBIA0057E

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CAMSHAFT VALVE CLEARANCE

• Thickness of a new valve lifter can be identified by stamp

marks on the reverse side (inside the cylinder).

Stamp mark 696 indicates a thickness of 6.96 mm (0.2740 in)

Available thickness of valve lifter: 26 sizes with a range of

7.88 to 8.38 mm (0.3102 to 0.3299 in), in steps of 0.02 mm

(0.0008 in), when assembled at the factory.

5. Install the selected valve lifter.
6. Install camshaft.
7. Instructionly turn crankshaft pulley a few turns.
8. Check that valve clearances for cold engine are within specifica-

tions, by referring to the specified values.

9. After completing the repair, check valve clearances again with the specifications for warmed engine. Use

a feeler gauge to measure the clearance between the valve and camshaft. Make sure the values are

within specifications.

* Approximately 80C

° (176°F)

Valve clearance standard:
Cold

Intake

: 0.24 - 0.32 mm (0.009 - 0.013 in)

Exhaust

: 0.26 - 0.34 mm (0.010 - 0.013 in)

Hot*

Intake

: 0.304 - 0.416 mm (0.012 - 0.016 in)

Exhaust

: 0.308 - 0.432 mm (0.012 - 0.017 in)

KBIA0119E

COMPRESSION PRESSURE

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COMPRESSION PRESSURE

Compression pressure

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CHECKING COMPRESSION PRESSURE

1. Warm up the engine to full operating temperature.
2. Release the fuel pressure. Refer to

EC-550, "Inspection"

(California),

EC-1038, "Inspection"

(Except Cali-

fornia).

3. Remove the ignition coil and spark plug from each cylinder.

Refer to

EM-14, "Removal and Installation"

.

4. Connect engine tachometer (not required in use of CONSULT-lIl).
5. Disconnect the fuel injector harness connector to avoid any residual fuel injection during the measure-

ment.

6. Install the compression tester with the adapter into the spark

plug hole.

• Use compression tester whose end (rubber portion) is smaller than

20 mm (0.79 in) in diameter. Otherwise, it may be caught by cylin-

der head during removal.

7. With the accelerator pedal fully depressed, turn the ignition switch to the “START” position to crank over

the engine. When the gauge pointer stabilizes, read the compression pressure and engine rpm. Perform

these steps to check each cylinder.

Unit: kPa (kg/cm

2

, psi) / rpm

CAUTION:

Always use a fully charged battery to obtain specified engine cranking speed.

• If the engine speed is out of specified rpm range, check the battery. Check engine speed again with a fully

charged battery.

• If compression pressure is below minimum value, check valve clearances and parts associated with com-

bustion chamber (valve, valve seat, piston, piston ring, cylinder bore, cylinder head, cylinder head gasket).

After the checking, measure compression pressure again.

• If some cylinders have low compression pressure, pour small amount of engine oil into the spark plug hole of

the cylinder to re-check it for compression.

• If the added engine oil improves the compression, the piston rings may be worn or damaged. Check the pis-

ton rings and replace if necessary.

KBIA0130E

SEM387C

Standard

Minimum

Difference limit between cylinders

1,250 (12.8, 181.3) / 250

1,060 (10.8, 153.7) / 250

100 (1.0, 14) / 250