Nissan Frontier D40. Manual - part 618

EM-204

< ON-VEHICLE REPAIR >

[VQ40DE]

CYLINDER HEAD

6.

Remove valve oil seals using Tool.

7.

If valve seat must be replaced, refer to 

EM-205, "Inspection After Disassembly"

.

8.

If valve guide must be replaced, refer to 

EM-205, "Inspection After Disassembly"

.

9.

Remove spark plug tube, as necessary.
• Using pair of pliers, pull spark plug tube out of cylinder head. 

CAUTION:

• Take care not to damage cylinder head.
• Once removed, spark plug tube will be deformed and cannot be reused. Do not remove it unless

absolutely necessary.

ASSEMBLY

1.

When valve guide is removed, install it. Refer to 

EM-205, "Inspection After Disassembly"

.

2.

When valve seat is removed, install it. Refer to 

EM-205, "Inspection After Disassembly"

.

3.

Install valve oil seals using Tool.

4.

Install valve spring seat.

5.

Install valves.
• Install it in the original position.

NOTE:
Larger diameter valves are for intake side.

6.

Install valve spring (uneven pitch type).
• Install narrow pitch end (paint mark) to cylinder head side

(valve spring seat side).

7.

Install valve spring retainer.

Tool number

: KV10107902 (J-38959)

WBIA0489E

Tool number

:

—

 (J-39386)

Height (H) (Without valve spring seat installed)

Intake and exhaust

: 14.3 - 14.9 mm (0.563 - 0.587 in)

WBIA0490E

SEM085D

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8.

Install valve collet.
• Compress valve spring using Tool, attachment and adapter

using Tool. Install valve collet with magnet hand.

CAUTION:

When working, take care not to damage valve lifter holes
or valve stems.

• Tap valve stem edge lightly with plastic hammer after installa-

tion to check its installed condition.

9.

Install valve lifter.
• Install it in the original position.

10. Install spark plug tube.

• Press-fit spark plug tube as follows:

a.

Remove old liquid gasket adhering to cylinder head mounting hole.

b.

Apply sealant to area within approximately 12 mm (0.47 in) from edge of spark plug tube press-fit side.
Use Genuine High Strength Locking Sealant or equivalent. Refer to 

GI-22, "Recommended Chemi-

cal Products and Sealants"

.

c.

Press-fit spark plug tube so that its height (H) is as specified
using suitable drift.

CAUTION:

• When press-fitting, take care not to deform spark plug

tube.

• After press-fitting, wipe off liquid gasket protruding onto

cylinder-head upper face.

11. Install spark plug.

Inspection After Disassembly

INFOID:0000000005274355

VALVE DIMENSIONS

• Check dimensions of each valve. For dimensions, refer to 

EM-242, "Standard and Limit"

.

• If dimensions are out of the standard, replace valve and check the valve seat contact.

VALVE GUIDE CLEARANCE

Valve Stem Diameter

Measure the diameter of valve stem with micrometer.

Valve Guide Inner Diameter

Measure the inner diameter of valve guide with inside micrometer.

Tool numbers

: KV10109220 (

—

)

: KV10116200 (J-26336-B)

: KV10115900 (J-26336-20)

WBIA0578E

Standard press-fit height (H)

: 38.1 - 39.1 mm (1.500 - 1.539 in)

PBIC2638E

Standard

Intake

: 5.965 - 5.980 mm (0.2348 - 0.2354 in)

Exhaust

: 5.955 - 5.970 mm (0.2344 - 0.2350 in)

SEM938C

EM-206

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CYLINDER HEAD

Valve Guide Clearance

(Valve guide clearance) = (Valve guide inner diameter) – (Valve stem diameter).

• If the calculated value exceeds the limit, replace valve and/or valve guide.

VALVE GUIDE REPLACEMENT

When valve guide is removed, replace with oversized [0.2 mm (0.008 in)] valve guide.

1.

To remove valve guide, heat cylinder head to 110

°

 to 130

°

C

(230

°

 to 266

°

F) by soaking in heated oil.

2.

Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US
ton, 2.0 Imp ton) pressure] or hammer and suitable tool.

WARNING:

Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.

3.

Ream cylinder head valve guide hole using suitable tool.

Standard

Intake and Exhaust

: 6.000 - 6.018 mm (0.2362 - 0.2369 in)

Valve guide clearance:

Standard

Intake

: 0.020 - 0.053 mm (0.0008 - 0.0021 in)

Exhaust

: 0.030 - 0.063 mm (0.0012 - 0.0025 in)

Limit

Intake

: 0.08 mm (0.003 in)

Exhaust

: 0.09 mm (0.004 in)

SEM008A

SEM931C

Valve guide hole diameter (for service parts):

Intake and exhaust

: 10.175 - 10.196 mm (0.4006 - 0.4014 in)

SEM932C

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4.

Heat cylinder head to 110

°

 to 130

°

C (230

°

 to 266

°

F) by soaking

in heated oil.

5.

Press valve guide from camshaft side to the dimensions as
shown using suitable tool.

WARNING:

Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.

6.

Apply reamer finish to valve guide using suitable tool.

VALVE SEAT CONTACT

• After confirming that the dimensions of valve guides and valves are

within the specifications, perform this procedure.

• Apply prussian blue (or white lead) onto contacting surface of valve

seat to check the condition of the valve contact on the surface.

• Check if the contact area band is continuous all around the circum-

ference.

• If not, grind to adjust valve fitting and check again. If the contacting

surface still has “NG” conditions even after the re-check, replace
valve seat.

VALVE SEAT REPLACEMENT

When valve seat is removed, replace with oversized [0.5 mm (0.020 in)] valve seat.
1.

Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess
in cylinder head. Set the machine depth stop to ensure this. Refer to 

EM-242, "Standard and Limit"

.

CAUTION:

Prevent to scratch cylinder head by excessive boring.

SEM008A

Projection “L”

Intake and exhaust

: 12.6 - 12.8 mm (0.496 - 0.504 in)

SEM950E

Standard:

Intake and exhaust

: 6.000 - 6.018 mm (0.2362 - 0.2369 in)

SEM932C

SBIA0322E