Yanmar 4LHA-HTP Operation Manual page 349

Chapter 2 Basic Engine
7. Crankshaft and Main Bearing
(2) Bending of the crankshaft
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.
( '
y
i —
T
V block
Crankshaft bend
(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.
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Dial gauge
n_j>
Sff
— 1
_ l
J —
\ /
V block
L e s s than 0.02mm (0.0007 in.)
Bend
Deflection
2-2S
• 4LHA Series
Crank journal
Crank pin