Yanmar 4JH2E Service Manual page 54

Chapter 2 Basic Engine
(i.
Crankshaft and Main Bearing
~~~~...;.~~~~~~~.;_~~~~~~~~~~~~~~~~~~~~~~~~~4JH2
Series
(2) Bending of the crani<shaft
Support the crankshaft with V·blocks at both ends
of the journals. Measure the deflection of the center
journal with a dial gauge while rotating the crankshaft
to check the extent of crankshaft bending.
Dial gauge
Bend
Deflection
v block
V block
Crankshaft bend Less than0.03mm (0.0012 in.)
(3) Measuring the crank pin and journal
Measure the extent of journal wear (roundness, taper).
Regrind it to the proper shape if it is within the outer
diameter limit, and replace if not.
Outside dia.
Crank pin Bushing inside dia
Crank pin and bushing oil clearance
Outside dia
Crank journal Bushing inside dia.
Crank journal and bushing oil clearance
Fillet rounding of crank pin and journal
Printed in Japan
A0Al029-9002
Crank journal
Crank pin
mm(in)
Standard
Wear limit
47.952
~
47.962 (1.8878
~
1.8882)
47.75 (1.8799)
48.000 ~ 48.045 (1.8897 ~ 1.8915)
48.10 (1.8937)
0.038
~ 0.093 (0.0014 ~ 0.0036)
0.25 (0.0098)
49.952
~
49.962 (1.9666
~
1.9670)
49. 75 (1.9586)
50.000
~
50.045 (1.9685
~
1.9702)
50.10 (1.9724)
0.038 ~
0.093 (0.0014
~
0.0036)
0.25 (0.0098)
3.500 ...... 3.800 (0.1377
~
0.1496)
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