NISSAN PICK-UP 1998 Repair Manual

SEM812F
CYLINDER BLOCKKA
EM-38

CAUTION:
lWhen installing sliding parts (bearings, pistons, etc.),
lubricate contacting surfaces with new engine oil.
lPlace removed parts such as bearings and bearing caps
in their proper order and direction.
lWhen installing connecting rod nuts and main bearing
cap bolts, apply new engine oil to threads and seating
surfaces.
lDo not allow any magnetic materials to contact the ring
gear teeth of flywheel or drive plate.
Disassembly
PISTON AND CRANKSHAFT
1. Remove intake manifold.
2. Place engine on a work stand.
3. Drain coolant and oil.
4. Remove oil pan.
5. Remove water pump.
6. Remove timing chain.
7. Remove cylinder head.
8. Remove pistons with connecting rod.
9. Remove bearing caps and crankshaft.
lBefore removing bearing caps, measure crankshaft end
play. Refer to EM-47.
lBolts should be loosened in two or three steps.
Inspection
PISTON AND PISTON PIN CLEARANCE
1. Measure inner diameter of piston pin hole ``dp''.
Standard diameter ``dp'':
21.002 - 21.008 mm (0.8268 - 0.8271 in)
2. Measure outer diameter of piston pin ``Dp''.
Standard diameter ``Dp'':
20.993 - 20.998 mm (0.8265 - 0.8267 in)
3. Calculate piston pin clearance.
dp þ Dp = 0.008 - 0.012 mm (0.0003 - 0.0005 in)
If it exceeds the above value, replace piston assembly with
pin.
SEM744-A
EEM118
AEM023
AEM024
CYLINDER BLOCKKA
EM-39

PISTON RING SIDE CLEARANCE
Side clearance: mm (in)
Top ring 0.01 - 0.03 (0.0004 - 0.0012)
2nd ring 0.03 - 0.07 (0.0012 - 0.0028)
Oil ring 0.085 - 0.115 (0.0033 - 0.0045)
Max. limit of side clearance:
0.1 mm (0.004 in)
If out of specification, replace piston ring.
If clearance exceeds maximum limit with new ring, replace pis-
ton.
PISTON RING END GAP
End gap: mm (in)
Top ring
0.28 - 0.43 (0.0110 - 0.0169)
2nd ring
0.45 - 0.60 (0.0177 - 0.0236)
(R or T is punched on the ring.)
0.55 - 0.70 (0.0217 - 0.0276)
(N is punched on the ring.)
Oil ring
0.20 - 0.60 (0.0079 - 0.0236)
Max. limit of ring gap:
0.5 mm (0.020 in)
If out of specification, replace piston ring. If gap exceeds maxi-
mum limit with a new ring, rebore cylinder and use oversized
piston and piston rings. Refer to SDS, EM-95.
lWhen replacing the piston, check cylinder block surface for
scratches or seizure. If scratches or seizure are found, hone
or replace the cylinder block.
CONNECTING ROD BEND AND TORSION
Bend: mm (in)
Limit 0.15 (0.0059) per 100 (3.94) length
Torsion: mm (in)
Limit 0.3 (0.012) per 100 (3.94) length
If it exceeds the limit, replace connecting rod assembly.
SEM249CA
SEM250C
SEM038F
SEM003F
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-40

CYLINDER BLOCK DISTORTION AND WEAR
1. Clean upper face of cylinder block.
Use a reliable straightedge and feeler gauge to check the
flatness of cylinder block surface. Check along six positions
shown in figure.
Limit:
0.1 mm (0.004 in)
2. If out of specification, resurface it.
The limit for cylinder block resurfacing is determined by cyl-
inder head resurfacing.
Amount of cylinder head resurfacing is ``A''
Amount of cylinder block resurfacing is ``B''
The maximum limit is as follows:
A+B=0.2mm(0.008 in)
Nominal cylinder block height
from crankshaft center:
246.95 - 247.05 mm (9.7224 - 9.7264 in)
3. If necessary, replace cylinder block.
PISTON-TO-BORE CLEARANCE
1. Using a bore gauge, measure cylinder bore for wear, out-of-
round and taper.
Standard inner diameter:
Refer to SDS, EM-91.
Wear limit: 0.2 mm (0.008 in)
Out-of-round (X þ Y) standard: 0.015 mm (0.0006 in)
Taper (A þ B) standard: 0.010 mm (0.0004 in)
If it exceeds the limit, rebore all cylinders. Replace cylinder
block if necessary.
2. Check for scratches and seizure. If seizure is found, hone it.
lIf cylinder block and piston are replaced, match piston
grade with grade number on cylinder block upper sur-
face.
3. Measure piston skirt diameter.
Piston diameter ``A'':
Refer to SDS, EM-95.
Measuring point ``a'' (Distance from the top):
Approximately 52 mm (2.05 in)
4. Check that piston-to-bore clearance is within specification.
Piston-to-bore clearance ``B'':
0.020 - 0.040 mm (0.0008 - 0.0016 in)
5. Determine piston oversize according to amount of cylinder
wear.
Oversize pistons are available for service. Refer to SDS,
EM-95.
SEM255CB
SEM619F
SEM257C
SEM258C
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-41

6. Cylinder bore size is determined by adding piston-to-bore
clearance to piston diameter ``A''.
Rebored size calculation:
D=A+BþC
where,
D: Bored diameter
A: Piston diameter as measured
B: Piston-to-bore clearance
C: Honing allowance 0.02 mm (0.0008 in)
7. Install main bearing caps and tighten bolts to the specified
torque. This will prevent distortion of cylinder bores.
8. Cut cylinder bores.
lWhen any cylinder needs boring, all other cylinders
must also be bored.
lDo not cut too much out of cylinder bore at a time. Cut
only 0.05 mm (0.0020 in) or so at a time.
9. Hone cylinders to obtain specified piston-to-bore clearance.
10. Measure finished cylinder bore for out-of-round and taper.
lMeasurement should be done after cylinder bore cools
down.
CRANKSHAFT
1. Check crankshaft main and pin journals for score, wear or
cracks.
2. With a micrometer, measure journals for taper and out-of-
round.
Out-of-round (X þ Y): mm (in)
Main journal Less than 0.01 (0.0004)
Crank pin Less than 0.005 (0.0002)
Taper (A þ B): mm (in)
Main journal Less than 0.01 (0.0004)
Crank pin Less than 0.005 (0.0002)
3. Measure crankshaft runout.
Runout (Total indicator reading):
Less than 0.10 mm (0.0039 in)
BEARING CLEARANCE
lUse Method A or Method B. Method A is preferred because
it is more accurate.
Method A (Using bore gauge and micrometer)
Main bearing
1. Set main bearings in their proper positions on cylinder block
and main bearing cap.
SEM316A
SEM254C
SEM448C
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-42

2. Install main bearing cap to cylinder block.
lTighten all bolts in correct order in two or three stages.
3. Measure inner diameter ``A'' of each main bearing.
4. Measure outer diameter ``Dm'' of each crankshaft main jour-
nal.
5. Calculate main bearing clearance.
Main bearing clearance=AþDm
Standard:
0.020 - 0.047 mm (0.0008 - 0.0019 in)
Limit:
0.1 mm (0.004 in)
6. If it exceeds the limit, replace bearing.
7. If clearance cannot be adjusted within the standard of any
bearing, grind crankshaft journal and use undersized bear-
ing.
a. When grinding crankshaft journal, confirm that ``L''
dimension in fillet roll is more than the specified limit.
``L'': 0.1 mm (0.004 in)
b. Refer to SDS for grinding crankshaft and available ser-
vice parts.
8. If crankshaft is reused, measure main bearing clearance and
select thickness of main bearing.
If crankshaft or cylinder block is replaced, select thickness of
main bearings as follows:
a. Grade number of each cylinder block main journal is punched
on the respective cylinder block. These numbers are
punched in either Arabic or Roman numerals.
EEM119
AEM026
SEM964
EEM120
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-43

b. Grade number of each crankshaft main journal is punched on
crankshaft. These numbers are punched in either Arabic or
Roman numerals.
c. Select main bearing with suitable thickness according to the
following example or table.
For example:
Main journal grade number: 1
Crankshaft journal grade number: 2
Main bearing grade number=1+2
= 3 (Yellow)
Main bearing grade number and identification color:
Main journal grade number
012
Crankshaft
journal grade
number0 0 (Black) 1 (Brown) 2 (Green)
1 or I 1 (Brown) 2 (Green) 3 (Yellow)
2 or II 2 (Green) 3 (Yellow) 4 (Blue)
Connecting rod bearing (Big end)
1. Install connecting rod bearing to connecting rod and cap.
2. Install connecting rod cap to connecting rod.
lTighten bolts to the specified torque.
3. Measure inner diameter ``C'' of each bearing.
4. Measure outer diameter ``Dp'' of each crankshaft pin journal.
5. Calculate connecting rod bearing clearance.
Connecting rod bearing clearance
= C þ Dp: mm (in)
Standard
0.010 - 0.035 (0.0004 - 0.0014)
Limit
0.09 (0.0035)
6. If it exceeds the limit, replace bearing.
7. If clearance cannot be adjusted within the standard of any
bearing, grind crankshaft journal and use undersized bear-
ing. Refer to step 7 of ``BEARING CLEARANCE Ð Main
bearing''.
SEM272C
AEM027
AEM028
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-44

8. If crankshaft is replaced, select connecting rod bearing
according to the following table.
Connecting rod bearing grade number:
These numbers are punched in either Arabic or Roman numer-
als.
Crank pin grade numberConnecting rod bearing
grade number
00
1orI 1
2orII 2
Method B (Using plastigage)
CAUTION:
lDo not turn crankshaft or connecting rod while plasti-
gage is being inserted.
lWhen bearing clearance exceeds the specified limit,
ensure that the proper bearing has been installed. Then
if excessive bearing clearance exists, use a thicker main
bearing or undersized bearing so that the specified bear-
ing clearance is obtained.
CONNECTING ROD BUSHING CLEARANCE (Small
end)
1. Measure inner diameter ``C'' of bushing.
2. Measure outer diameter ``Dp'' of piston pin.
3. Calculate connecting rod bushing clearance.
CþDp=
þ0.015 to þ0.033 mm (þ0.0006 to þ0.0013 in) (Stan-
dard)
If out of specification, replace connecting rod assembly
and/or piston set with pin.
FLYWHEEL RUNOUT
Runout (Total indicator reading):
Flywheel Less than 0.1 mm (0.004 in)
CAUTION:
Do not allow any magnetic materials to contact the ring gear
teeth.
Assembly
PISTON
1. Heat piston to 60 to 70ÉC (140 to 158ÉF) and assemble
piston, piston pin and connecting rod.
lAlign the direction of piston and connecting rod.
lNumbers stamped on connecting rod and cap corre-
spond to each cylinder.
lAfter assembly, make sure connecting rod swings
smoothly.
SEM567B
EM142
SEM245E
AEM100
SEM262C
CYLINDER BLOCKKA
Inspection (Cont'd)
EM-45

2. Set piston rings as shown.
CAUTION:
lWhen piston rings are not replaced, make sure that pis-
ton rings are mounted in their original positions.
lWhen piston rings are being replaced and no punchmark
is present, piston rings can be mounted with either side
up.
3. Align piston rings so that end gaps are positioned as shown.
CRANKSHAFT
1. Set main bearings in their proper positions on cylinder block
and main bearing caps.
lConfirm that correct main bearings are used. Refer to
EM-42.
lApply new engine oil to bearing surfaces.
2. Install crankshaft and main bearing caps and tighten bolts to
the specified torque.
lApply new engine oil to the bolt threads and seat sur-
face.
lPrior to tightening bearing cap bolts, place bearing cap
in its proper position by shifting crankshaft in the axial
direction.
lTighten bearing cap bolts gradually in two or three
stages. Start with center bearing and move outward as
shown in figure.
lAfter securing bearing cap bolts, make sure crankshaft
turns smoothly by hand.
SEM215EA
SEM264C
SEM160B
SEM448C
EEM121
CYLINDER BLOCKKA
Assembly (Cont'd)
EM-46

3. Measure crankshaft end play.
Crankshaft end play: mm (in)
Standard
0.05 - 0.18 (0.0020 - 0.0071)
Limit
0.3 (0.012)
If beyond the limit, replace bearing with a new one.
4. Install connecting rod bearings in connecting rods and con-
necting rod caps.
lConfirm that correct bearings are used.
Refer to EM-45.
lInstall bearings so that oil hole in connecting rod aligns
with oil hole of bearing.
lApply new engine oil to bearing surfaces, bolt threads
and seating surfaces.
5. Install pistons with connecting rods.
a. Install them into corresponding cylinders with Tool.
lArrange so that front mark on piston head faces toward
front of engine.
lMake sure connecting rod does not scratch cylinder
wall.
lMake sure connecting rod bolts do not scratch crank-
shaft journals.
lApply new engine oil to piston rings and sliding surface
of piston.
b. Install connecting rod bearing caps.
Tighten connecting rod bearing cap nuts using the following
procedure.
Connecting rod bearing nut:
(1) Tighten to 14 to 16 N´m
(1.4 to 1.6 kg-m, 10 to 12 ft-lb).
(2) Tighten bolts 60
+5
þ0degrees clockwise
with an angle wrench.
If an angle wrench is not available, tighten
them to 38 to 44 N´m (3.9 to 4.5 kg-m, 28 to 33
ft-lb).
6. Measure connecting rod side clearance.
Connecting rod side clearance: mm (in)
Standard
0.2 - 0.4 (0.008 - 0.016)
Limit
0.6 (0.024)
If beyond the limit, replace connecting rod and/or crankshaft.
EEM122
SEM159B
SEM269CA
EEM123
EEM124
CYLINDER BLOCKKA
Assembly (Cont'd)
EM-47