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ENGINE MAIN PARTS - INSPECTION AND CORRECTION
2 - 27
3. Cylinder
Block,
Crankshaft, Pistons, Oil Pan
3.1 Measuring the piston diameter
Using a micrometer, measure the piston diameter
across the piston skirt and squarely with the
piston pin, as illustrated.
If the measured value is less than the limit,
replace with a new part. The maximum
allowable variation in weight among the pistons
on the same engine is 5 grams (0.18 oz).
Unit: mm (in.)
Nominal
value
Standard
value
Limit
STD
78.00
(3.07)
77.93 to 77.95
(3.070 to 3.071)
77.80
(3.065)
0.25
OS
78.25
(3.08)
78.18 to 78.20
(3.080 to 3.081)
78.05
(3.075)
Piston
diameter
0.50
OS
78.50
(3.09)
78.43 to 78.45
(3.090 to 3.090)
78.30
(3.085)
Max. allowable variation in
weight among pistons on the
same engine:
5 g (0.18 oz)
or less
―
3.2 Measuring the clearance between the
piston ring and the ring groove
(1)
Measure the piston ring-to-groove clearance. If
the measured value exceeds the limit, replace the
piston ring.
Unit: mm (in.)
Standard
value Limit
No. 1 ring 0.09 to 0.11 (0.0035 to 0.0043) 0.300 (0.012)
No. 2 ring 0.07 to 0.11 (0.0028 to 0.0043) 0.200 (0.008)
Oil ring
0.03 to 0.07 (0.0012 to 0.0028) 0.200 (0.008)
(2)
With the new piston ring installed, measure the
ring-to-groove clearance again. If the measured
value still exceeds the limit, replace the piston.
3.3 Measuring the piston ring gap
Install the piston ring being measured into the
gauge or a new cylinder. Then, using a thickness
gauge, measure the piston ring gap. If the
measured value exceeds the limit, replace all
rings of the relevant piston as a set.
STD=78
+0.03
0
mm (3.07
+0.0012
0
in.)
Gauge bore size 25 OS=78.25
+0.03
0
mm (3.08
+0.0012
0
in.)
50 OS=78.50
+0.03
0
mm (3.09
+0.0012
0
in.)
Note: To install a piston ring into the gauge, use a
piston to push the ring evenly.
Unit: mm (in.)
Standard
value
Limit
No. 1 ring 0.15 to 0.30 (0.006 to 0.012)
No. 2 ring 0.15 to 0.35 (0.006 to 0.014)
Piston
ring
gap
Oil ring
0.20 to 0.40 (0.008 to 0.016)
1.50
(0.06)
Measuring the piston diameter
Measuring the piston ring-to-groove clearance
Measuring the piston ring gap
Measuring location
Measure squarely
with piston pin
Thickness gauge
No. 1 piston
ring-to-groove
clearance
No. 2 piston
ring-to-groove
clearance
Summary of Contents for diesel engines
Page 5: ......
Page 33: ...SERVICE STANDARDS 1 20 ...
Page 34: ...1 General Tools 1 22 2 Special Tools 1 23 TOOLS LIST ...
Page 37: ...TOOLS LIST 1 24 ...
Page 41: ...OVERHAUL TIMING 1 28 ...
Page 46: ......
Page 47: ......
Page 61: ...ENGINE MAIN PARTS DISASSEMBLY 2 16 ...
Page 99: ...FUEL SYSTEM REMOVAL 3 8 ...
Page 115: ...FUEL SYSTEM DISASSEMBLY INSPECTION AND REASSEMBLY 3 24 ...
Page 119: ...FUEL SYSTEM INSTALLATION 3 28 2 Governor Installing the governor Installation sequence ...
Page 123: ...FUEL SYSTEM INSTALLATION 3 32 ...
Page 131: ...OIL SYSTEM DISASSEMBLY INSPECTION AND REASSEMBLY 4 8 ...
Page 143: ...COOLING SYSTEM DISASSEMBLY INSPECTION AND REASSEMBLY 5 8 ...
Page 150: ......
Page 151: ......
Page 153: ...INLET AND EXHAUST SYSTEMS REMOVAL 6 4 ...
Page 159: ...INLET AND EXHAUST SYSTEMS INSTALLATION 6 10 ...
Page 160: ...1 Starter 7 2 2 Alternator 7 3 3 Stop Solenoid 7 4 4 Glow Plug 7 5 ELECTRICAL SYSTEM REMOVAL ...
Page 165: ...ELECTRICAL SYSTEM REMOVAL 7 6 ...
Page 189: ...ELECTRICAL SYSTEM INSTALLATION 7 30 ...
Page 207: ...MISCELLANEOUS 9 4 ...