Operation Manual

Job Card No.:
Engine:
Filing No.:
Gauging
Main and big-end bearing shells to be fitted must
have sufficient positive spread, so they will have
preload in their receiving bores.
All new shells have apositive spread unless
they have been improperly handled, for in-
stance in transit.
Job:
The spread is positive when - measured at room
temperature - dimension "a" is larger than "D" which
is stamped on the shell back. (If illegible, see table
below.)
If a used shell has a negative spread ("a" smaller than
"D"), this may suggest that the bearing has been
strained by overheating and thus has lost preload.
Descard shells with negative spread, because the
inner edges of such "loose" shells are liable to cut off
the oil film on the shaft journal or crankpin respec-
tively.
Do not perform a correction with own means, as
there is a risk that the bearing metal may detach from
the support shell or the bearing may become defor-
med. Damage of this kind may lead to serious opera-
ting faults.
Bearing Shell Spread
Gauging
0178-06-10 1603
02.03.02
S/BV M 628
„D“ stamped here
Main Bearing Big-end Bearing
„D“ „D“
Nominal
Ø 220,0
+0,029
Ø 182,0
+0,029
size 0,000 0,000
Under-
Ø 220,5
+0,029
size 0,000
Under-
Ø 221,0
+0,029
size 0,000
Under-
Ø 221,5
+0,029
size 0,000
Under-
Ø 222,0
+0,029
size 0,000
Tools:
- Caliper gauge
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