IO-390-D Series Engine Maintenance Manual
72-20
© 2020 Avco Corporation. All Rights Reserved
Page 130
March 2020
IO-390-D Series Engine Maintenance Manual
3.
Crankcase Disassembly
A.
Put the crankcase upright on a suitable work
surface
B.
Crankshaft Idler Gear and Bushing Removal
(1)
Remove the idler gears and bushings (Figure 2)
from the idler gear shafts.
(2)
Discard the bushings.
Figure 2
Crankshaft Idler Gears
CAUTION
TO PREVENT DAMAGE TO THE CRANKCASE, REMOVE ALL THRU-
STUDS, NUTS, AND BOLTS FROM THE CRANKCASE HALVES
BEFORE SEPARATION OF THE CRANKCASE HALVES.
C.
Use a slide hammer, a Crankcase Thru-
Stud Puller ST-271 or Crankcase Thru
Stud Driver ST-317 or a plastic hammer
to remove the four thru-studs from the
crankcase (Figure 3).
D.
Remove the remaining bolts and nuts
that attach the crankcase halves.
E.
Insert one used pushrod into each of the
four holes where the thru-studs were
removed to support the camshaft and
crankshaft when the crankcase halves are
separated.
Figure 3
Crankcase Assembly
F.
Separate the crankcase with a Crankcase Separating Tool ST-389 or with a slide-hammer
attached to one of the base studs as shown in Figures 4, 5, and 6.
Figure 4
Attach the Slide-Hammer
to a Base Stud
Figure 5
Strike the Slide Part of the Tool
Against the Back of the Tool
Figure 6
Separate the
Crankcase Halves
