a few slight blows by a hammer are applied. If this is
not the case you could not feel whether or not the
bearing already contacts the collar (see Fig.
3).
I.'&
13.
Inserting the right-hand crankshaft bearing
One vigorous blow by a hammer more than required
may cause the following:
The crankshaft is exposed to axial thrust because the
bearing was driven in too deep. The inner race presse.i
back the slightly resilient crankshaft. As a conse-
quence, the bearing clearance (lubrication film!) in the
left-hand bearing is also removed. The balls no longer
bear radially but run on the sides, producing
a
"whin-
ing" sound until they will fail prematurely.
Fig.
44.
Distorted bearing
Fig.,
45.
Displaced crankshaft
If the blows applied were still heavier, the crankshaft
will be laterally displaced and will
be
forced out of
true; then it is useless for the following reasons:
1.
The contact breaker fails to lift at the specified
point or the adjusting range of the contact-breaker
base plate will become insufficient.
2.
The amount the crankshaft is out of true will cause
the engine to. vibrate and, as a consequence, the
warranted engine output will no longer
be
reached.
If
the bearing is driven in with undue force into the
cold casing and without the inner race being heated,
there is the additional risk of the outer race becoming
tilted, i.e. it will not fit axially parallel.
In addition to the state described in Fig.
44,
the casing
becomes useless.
A
correctly mounted bearing would
again be tilted because of the damaged seat of the
bearing.
(For a better demonstration, the representation of the
sketches is slightly exaggerated.)
Fig.
46.
Tilted bearing
Meanwhile the inner race of the third crankshaft bear-
ing has been heated to about
80
"C.
The casing is
turned in the assembling device through
180"
and the
bearing driven in until it contacts the lock ring by
means of the
11-MW
7-4
drift.
Fig.
47.
Inserting the crankshaft bearing at the left-hand
,
side
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