Yanmar 2TNV70 Service Manual page 101

(d) Rod big end measurement
Measure the crankpin outside diameter.
The oil clearance is calculated as the difference in the
crankpin outside diameter and the crank pin metal
inside diameter (refer to 4.4.5.(2)(c) ).
Replace the crankpin metal if a clearance becomes
close to the limit value in the table below.
If wear and unevenly wear on the crankpin is found,
correct by grinding the crankpin and apply the
undersized bushing (refer to 4.4.5.(2)(c) )
[NOTICE]
When measuring the inside diameter of the rod big
end, install the bushing in the rod big end not to
mistake top and bottom of the crankpin metal and
fasten the rod bolts by the standard torque shown in
the table.
Tightening torque of rod bolt
Tightening torque
22.6 27.5(2.3 2.8)
Standard of rod big end
Item Standard
Crankpin O.D. 41.952 41.962
Metal I.D. 41.982 42.002
Metal thickness 1.503 1.509
Clearance 0.020 0.058
(6) Tappet
Mainly check the tappet contact surface with the cam
and push rod. Slight surface defects shall be
corrected with an oilstone.
Tappet stem outside diameter measurement
The outside diameter of the tappet stem is measured
by a micrometer.
The clearance is calculated from the measured tappet
hole and the measured stem diameter.
Item Standard
Tappet hole I.D. 21.000 21.021
Stem O.D. 20.927 20.960
Clearance 0.040 0.094
N m(kgf-m)
Lube oil application
(threaded portion,
and bearing seat surface)
Lube. oil applied
mm
Limit
41.900
-
-
0.120
mm
Limit
21.041
20.907
0.134
4. Disassembly, Inspection and Reassembly of Engines
86