1998 NISSAN PICK-UP Repair Manual

Removal
Removal order and pointsApplied model
2WD 4WD
1 Remove undercover.jj
2 Drain engine oil.jj
3Remove front propeller shaft
from front differential carrier.Ðj
4Remove front drive shaft fix-
ing bolts (RH & LH).Ðj
5Remove front suspension
crossmember.jj
6Remove differential front
mounting bolts (RH & LH)
and rear mounting bolts.Ðj
7Remove front differential car-
rier.ÐjRemoval order and pointsApplied model
2WD 4WD
8Remove front differential car-
rier mounting bracket.Ðj
9Remove transmission to rear
engine mounting bracket
nuts (RH & LH).jj
10Remove engine mounting
bolts or nuts (RH & LH).jj
11Lift up engine.
If necessary, disconnect
exhaust tube.jj
12 Remove oil pan.jj
WARNING:
lPlace vehicle on a flat and solid surface.
lPlace chocks at front and rear of rear wheels.
lYou should not remove oil pan until exhaust system and
cooling system have completely cooled off.
Otherwise, you may burn yourself and/or fire may break
out in the fuel line.
lWhen removing front and/or rear engine mounting bolts
or nuts, lift up slightly engine for safety work.
CAUTION:
lIn lifting engine, be careful not to hit against adjacent
parts, especially against accelerator wire casing end,
brake tube and brake master cylinder.
lFor tightening torque, refer to EM-71, MT and PD sec-
tions.
Remove oil pan bolts in order shown.
Installation
1. Install the oil pan gasket with the coated surface facing the
cylinder block and the notch facing the rear of the engine.
2. Tighten all bolts in reverse order of removal. For tightening
torque of oil pan and correct installing direction of drain plug
washer, refer to EM-71.
DEM022
DEM023
OIL PANTD
EM-52

DEM110
CYLINDER HEADTD
EM-53

CAUTION:
lWhen installing sliding parts such as rocker arms, cam-
shaft and oil seal, be sure to apply new engine oil on
their sliding surfaces.
lWhen tightening cylinder head bolts and rocker shaft
bolts, apply new engine oil to thread portions and seat
surfaces of bolts.
Removal
1. Set No. 1 cylinder at TDC (top dead center) on its compres-
sion stroke.
2. Drain engine coolant from drain plugs on cylinder block and
radiator.
3. Remove air cleaner and/or air duct.
4. Remove alternator adjusting bolt.
5. Disconnect exhaust manifold from front exhaust tube.
6. Disconnect radiator outlet hose and thermostat housing
water inlet hose.
7. Remove air intake housing.
8. Remove fuel injection tube assembly and spill tube.
9. Remove injection nozzle holder and top nozzle gasket using
deep socket wrench.
MEM125A
DEM024
DEM025
DEM026
CYLINDER HEADTD
EM-54

10. Remove rocker cover.
11. Remove rocker shaft with rocker arms.
12. Remove push rods.
13. Remove cylinder head bolts in numerical order and remove
cylinder head.
Head warpage or cracking could result from removing in
incorrect order.
Disassembly
1. Remove following parts:
a. Intake manifold
b. Exhaust manifold
c. Thermostat housing
d. Alternator adjusting bar & engine slinger
e. Glow plate and glow plugs
2. Remove valve component parts with Tool.
SEM607F
DEM028
SEM623B
SEM624B
DEM029-A
CYLINDER HEADTD
Removal (Cont'd)
EM-55

3. Remove valve oil seals with Tool.
4. Disassemble rocker shaft assembly.
a. Remove rocker shaft lock bolt.
b. Remove valve rocker and rocker shaft bracket.
If it is difficult to remove rocker shaft bracket, immerse
rocker shaft assembly in oil of 70ÉC (158ÉF) for a few min-
utes and then remove bracket.
Inspection
CYLINDER HEAD DISTORTION
Cylinder head distortion: mm (in)
Standard
Less than 0.07 (0.0028)
Limit
0.2 (0.008)
If beyond the specified limit, correct with a surface grinder. Cyl-
inder head height should be greater than 89.7 mm (3.531 in)
after surface has been ground.
VALVE GUIDE CLEARANCE
lValve guide clearance should be measured parallel with
rocker arm. (Generally, a large amount of wear occurs in
this direction.)
Stem to guide clearance: mm (in)
Limit
Intake 0.15 (0.0059)
Exhaust 0.20 (0.0079)
Maximum allowable deflection
(Dial indicator reading)
Intake 0.30 (0.0118)
Exhaust 0.40 (0.0157)
lTo determine the correct replacement part, measure
valve stem diameter and valve guide inner diameter.
Valve stem diameter: mm (in)
Standard
Intake
7.962 - 7.977 (0.3135 - 0.3141)
Exhaust
7.945 - 7.960 (0.3128 - 0.3134)
SEM626BA
SEM627B
SEM648B
SEM586A
EM030
CYLINDER HEADTD
Disassembly (Cont'd)
EM-56

Valve guide inner diameter:
8.000 - 8.015 mm (0.3150 - 0.3156 in)
VALVE GUIDE REPLACEMENT
1. 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.
2. Press service valve guide onto cylinder head using suitable
tool until the guide projects out 15.8 to 16.2 mm (0.622 to
0.638 in).
3. Ream valve guide.
Finished size:
8.000 - 8.015 mm (0.3150 - 0.3156 in)
VALVE SEATS
Check valve for any evidence of pitting at valve contact surface,
and reseat or replace if worn out excessively.
lWhen repairing valve seats, check valve and valve guide
for wear beforehand. If worn, replace them. Then correct
valve seat.
lThe cutting should be done with both hands for uniform
cutting.
SEM649B
SEM628B
SEM629BA
SEM630B
SEM024-A
CYLINDER HEADTD
Inspection (Cont'd)
EM-57

REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses or remove valve seats with
Tool.
Place a copper seat between contact surface of Tool and
cylinder head.
2. If the valve seat for the exhaust side is oversized, machine
its mating area (on the cylinder head side) to the dimensions
indicated in the table below. Refer to the figure at the left for
machining procedures.
Unit: mm (in)
Oversized valve
seatBore diameter ``d''
TD25
0.2 (0.008)38.695 - 38.710
(1.5234 - 1.5240)
0.4 (0.016)38.895 - 38.910
(1.5313 - 1.5319)
3. Place new valve seats on dry ice and allow them to cool for
five minutes.
WARNING:
Do not touch cooled valve seats with bare hand.
4. Heat cylinder head to 80ÉC (176ÉF).
5. Install cooled valve seats on cylinder head with Tool.
6. Stake exhaust valve seat at five places with punch.
When staking valve seat, select different places than those
staked before.
SEM631B
DEM031
SEM632B
SEM087
CYLINDER HEADTD
Inspection (Cont'd)
EM-58

7. Cut or grind valve seat using suitable tool at the specified
dimensions as shown in SDS, EM-100.
8. After cutting, lap valve seat with a lapping compound.
9. Check contact condition of valve seat.
COMBUSTION CHAMBER
Check combustion chamber for cracks and other damage. If
necessary, replace.
REPLACING COMBUSTION CHAMBER
Usually combustion chamber should not be removed.
1. Remove combustion chamber so that cylinder head cannot
be damaged.
2. Install combustion chamber.
Identification of combustion chambers
Identification mark
(on combustion chamber)Outer diameter
``D'' mm (in)Engine
3 places 37 (1.46) TD25
(1) Cool combustion chamber with dry ice for approximately 5 to
10 minutes.
WARNING:
Do not touch cooled combustion chamber with bare hand.
(2) Align combustion chamber knock pin with cylinder head
notch, and drive in combustion chamber with a soft hammer.
3. Check amount of protrusion of combustion chamber.
Protrusion:
Standard
þ0.05 to 0.10 mm (þ0.0020 to 0.0039 in)
VALVE DIMENSIONS
Check dimensions in each valve. For dimensions, refer to SDS.
When valve head has been worn down to 0.5 mm (0.020 in)
in margin thickness, replace the valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 in) or
less.
SEM633B
DEM107
.
SEM634B
SEM188A
CYLINDER HEADTD
Inspection (Cont'd)
EM-59