Onan NHC Series Operator's/Service Manual And Parts Catalog page 121

outside end of the bearing bore. Press the rear bearing
in u n t i l past the ignition plunger hole.
New crankshaft main bearings are precision type which
do not require line reaming or line boring after installa-
t i o n . They are available in standard size, .002", .010",
.020 " or .030 " undersize.
Before putting in the main, bearings, expand the bearing
bore by placing the casting in hot water or in an oven
heater to 200 0 F . I f practical, cool the precision bear-
ing to shrink i t .
For putting i n either the front or rear main bearing,,
using instructions f o l l o w i n g , always align the o i l
hole(s) i n the bearing with the o i l hole(s) in the bearing
bore. The o i l passage must be at least 1/2 open.
The, cold oiled precision bearing should require only
light taps to position i t .
NOTE: Engines shipped frotn the factory have separate
thrust washers and main, bearings for both front and rear
of engine. Front bearing replacement part is a one
piece bearing (with attached thrust washer) as shown
in Figure 55. Do not add an additional thrust washer
to this front bearing.
In the rear bearing plate, install the bearing flush to
1 / 6 4 " below the end of the bore using combination
driver 420B324 (same one used for camshaft bearing).
See Figure 54.
R E A R B E A R I N G E N D P L A T E
L O C K P I N
A L I G N B E A R I N G O I L H O L E S
W I T H O I L H O L E S IN B E A R
ING B O R E
T H R U S T
W A S H E R
S H I M
B E A R I N G
P R E C I S I O N T Y P E - O O N O T L I N E R E A M O R B O R E
F I G U R E 5 4 . B E A R I N G S FOR R E A R B E A R I N G P L A T E
NOTE: If the special combination tool isn't available,
it's necessary to remove the lock pins with side cutters
or Easy Out tool. After the new bearings are installed,
insert new lock pins.
Before i n s t a l l i n g the front bearing (Figure 55), use the
Locktite Bearing Mount furnished in the bearing k i t .
Use the towelette in the package to clean the outside
of the bearing and the bearing bore in the block.
N O T E : Do not add a d d i t i o n a l
t h r u s t w a s h e r w h e n r e p l a c -
i n g f r o n t b e a r i n
F R O N T M A I N
B E A R I N G B O R E
A L I G N B E A R I N G
N O T C H E S W I T H ,
L O C K P I N S
A N D M A T C H
O I L H O L E S
F R O N T
M A I N B E A R I N G
P R E C I S I O N T Y P E -
D O N O T L I N E B O R E O R R E A M O R B O R E
F I G U R E 5 5 . F R O N T B E A R I N G I N S T A L L A T I O N
WARNING
^ Breathing
vapor from towelette and
prolonged contact with skin can be
harmful. Be sure area is well ventilated.
After allowing three to four minutes for drying, apply,
the Locktite .Bearing Mount from the small tube to the
mating surfaces of the bearing and bearing bore. Install
the bearing flush with the block using the combination
driver just used for the rear bearing. Wipe off any
excess Locktite around the bearing. Allow at least one
hour for hardening at room temperature.
Lubricate the front main bearing lightly with o i l and
insert the crankshaft. With the rear bearing plate gasket
in place and the rear plate bearing lubricated, slide
the thrust washer (grooves toward crankshaft) and plate
over the end of the crankshaft. Line up the notches of
the thrust washer with the lock pins before tightening
the end plate or the lock pins w i l l be damaged.
NOTE: A light film of oil on the thrust washer may hold
it in place while installing the crankshaft.
CRANKSHAFT ENDPLAY
After the rear bearing end plate has been tightened
using the torque recommended in Assembly Torques
and Special Tools, check the crankshaft endplay as
shown in Figure 56. If there is too much endplay (see
Dimensions and Clearances for minimum and maximum
endplay), remove the rear bearing end plate and add a
shim (Figure 54) between the thrust washer and plate.
Reinstall the end. plate making sure the thrust washer
and shim notches line up with the lock pins. Torque
and recheck endplay of the crankshaft.
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