Nissan Terrano r20e. Manual — part 296
I
If clearance exceeds the limit, or any flaws or seizures are
found on inner surface of cylinder, horn or bore the applicable
cylinder.
Piston outer diameter
Use micrometer to measure piston skirt outer diameter.
Measurement position:
10 mm (0.39 in) upper from the lower end of pis-
ton
Standard:
95.950 - 95.980 mm (3.7776 - 3.7787 in) dia.
Calculation of piston to piston bore clearance
I
Calculate using piston skirt outer diameter and cylinder inner
diameter (direction X, position B).
Clearance = Cylinder inner diameter − Piston skirt outer diam-
eter
Specifications at room temperature [20°C (68°F)]:
0.040 - 0.060 mm (0.0016 - 0.0024 in)
I
If out of specification, replace piston and piston pin assembly.
SELECTIVE PISTON COMBINATION
When using new cylinder block
I
Confirm cylinder bore grade (1, 2, 3) on left upper surface of
cylinder block, and refer to “Selective combination chart” below
to select appropriate piston.
I
Part No. is given to a piston and piston pin as a set.
When re-using an old cylinder block
1. Measure cylinder block bore inner diameter.
2. Referring to “Cylinder block bore inner diameter” in “Selective
combination chart”, select appropriate piston according to cyl-
inder bore grade.
FEM110
FEM111
FEM112
FEM113
CYLINDER BLOCK
ZD
Inspection (Cont’d)
EM-75
Selective combination chart
Unit: mm (in)
q
: Preferable combination
g
: Allowable combination
X: NG combination
Piston grade
1
2
95.950 - 95.960
(3.7776 - 3.7779)
95.960 - 95.970
(3.7779 - 3.7783)
Cylinder
bore grade
(Cylinder
block bore
inner
diameter)
1
96.000 - 96.010
(3.7795 - 3.7799)
q
X
2
96.010 - 96.020
(3.7799 - 3.7803)
g
q
3
96.020 - 96.030
(3.7803 - 3.7807)
g
q
I
Piston grade 3 (95.980/95.970) is applicable at factory only.
I
New pistons are classified into 4 weight classes at factory. The
same class pistons are used on a engine.
Weight grade symbol
Weight class g (oz)
E
600 - 605 (21.2 - 21.3)
F
605 - 610 (21.3 - 21.5)
G
610 - 615 (21.5 - 21.7)
H
615 - 620 (21.7 - 21.9)
CRANKSHAFT JOURNAL OUTER DIAMETER
Use micrometer to measure journal outer diameter.
Standard: 70.907 - 70.920 mm (2.7916 - 2.7921 in) dia.
CRANKSHAFT PIN OUTER DIAMETER
Use micrometer to measure pin outer diameter.
Standard: 56.913 - 56.926 mm (2.2407 - 2.2412 in) dia.
CRANKSHAFT OUT-OF-ROUND AND TAPER
I
Using micrometer, measure each journal and pin at 4 points
shown in the figure.
I
Out-of-round value is indicated by difference in dimensions
between directions A and B at points 1 and 2.
I
Taper value is indicated by difference in dimensions between
points 1 and 2 in directions A and B.
Out-of-round limit: 0.01 mm (0.0004 in)
Taper limit: 0.01 mm (0.0004 in)
CRANKSHAFT RUNOUT
I
Place V-block onto surface plate to support journals at both
ends of crankshaft.
I
Position dial indicator vertically onto No. 3 journal.
I
Rotate crankshaft to read needle movement on dial indicator.
I
Crankshaft bend value is 1/2 of needle movement.
Limit: 0.03 mm (0.0012 in)
FEM114
FEM115
FEM116
CYLINDER BLOCK
ZD
Inspection (Cont’d)
EM-76
CONNECTING ROD BEARING OIL CLEARANCE
Method by measurement
I
Install connecting rod bearings to connecting rods and caps,
and tighten connecting nuts to the specified torque. Use inside
micrometer to measure connecting rod bearing inner diameter.
Bearing clearance = Connecting rod bearing inner diameter −
Crankshaft pin outer diameter
Standard: 0.035 - 0.077 mm (0.0014 - 0.0030 in)
I
If out of specifications, check connecting rod big end inner
diameter and crankshaft pin outer diameter, and select appro-
priate connecting rod bearing to adjust clearance to specifica-
tions.
Refer to “Connecting rod bearing undersize list” on the next
page.
Method using plastigage
I
Remove contamination such as oil, dust completely from crank-
shaft pins and each bearing surface.
I
Cut plastigage slightly shorter than bearing width, place it in
crankshaft direction, avoiding oil holes.
I
Install connecting rod bearings to caps, and tighten connecting
rod nuts to the specified torque.
CAUTION:
Never rotate crankshaft.
I
Remove connecting rod caps and bearings, and measure plas-
tigage width using scale on plastigage bag.
CAUTION:
If out of specification, take same action mentioned in “Method
by measurement”.
Undersize bearing usage
I
If bearing clearance is out of specifications for connecting rod
bearings in standard size, use undersize bearings.
I
When using undersize bearings, measure bearing inner diam-
eter with bearing installed, and grind pins to adjust clearance
to specification.
FEM103
FEM118
CYLINDER BLOCK
ZD
Inspection (Cont’d)
EM-77
Connecting rod bearing undersize list
Unit: mm (in)
Size
Thickness
US 0.25 (0.0098)
1.630 - 1.638 (0.0642 - 0.0645)
US 0.50 (0.0197)
1.755 - 1.763 (0.0691 - 0.0694)
US 0.75 (0.0295)
1.880 - 1.888 (0.0740 - 0.0743)
US 1.00 (0.0394)
2.005 - 2.013 (0.0789 - 0.0793)
CAUTION:
When grinding crank pins to use undersize bearings, avoid
damaging corners of fillet.
Corner dimension (Standard):
Pin
3.3 - 3.7 mm (0.130 - 0.146 in)
Journal
2.8 - 3.2 mm (0.110 - 0.126 in)
MAIN BEARING OIL CLEARANCE
Method by measurement
I
Install main bearings to cylinder block and bearing caps, and
tighten bearing cap bolts to the specified torque. Measure main
bearing inner diameter.
Bearing clearance = Bearing inner diameter − Crankshaft jour-
nal outer diameter
Standard: 0.035 - 0.083 mm (0.0014 - 0.0033 in)
I
If out of specification, check main bearing housing inner diam-
eter and crankshaft journal outer diameter, and select appropri-
ate main bearing to adjust clearance to specifications.
Refer to “Main bearing undersize list” on the next page.
Method using plastigage
I
Remove contamination such as oil, dust completely from crank-
shaft journals and each bearing surface.
I
Cut plastigage slightly shorter than bearing width, place it in
crankshaft direction, avoiding oil holes.
I
Install main bearings to caps, and tighten connecting rod nuts
to the specified torque.
CAUTION:
Never rotate crankshaft.
I
Remove bearing caps and bearings, and measure plastigage
width using scale on plastigage bag.
FEM119
FEM120
CYLINDER BLOCK
ZD
Inspection (Cont’d)
EM-78
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст