Onan NHC Series Operator's/Service Manual And Parts Catalog page 122

R E A R
IIIIIIIII
e
M E A S U R E E N D P L A Y H E R E J
( R E F E R T O D I M E N S I O N S
A N D C L E A R A N C E S ) '
F I G U R E 5 6 . C R A N K S H A F T E N D P L A Y
OIL SEALS
The bearing plate must be removed to replace its o i l
seal, drive the o i l seal out from the inside using
bearing plate driver 420B181 and gear cover driver
420B313.
Before installing the seals, f i l l the space between
seals with a fibrous grease or s t i f f cup-grease. This
w i l l improve sealing (see Figure 57).
When installing t h e e e a r
inward u n t i l it is
rover o i l seal, tap the seal
Df an inch from the mounting
face of the cover.'"-ftlSfall new style, thin open face
seal, 1-7/64 inches from mounting face of cover.
When installing the bearing plate o i l seal, tap the
seal into the. bearing plate bore to bottom against
the shoulder in the plate bore. Use a seal expander,
or place a piece of shim stock around the end of the
crankshaft,-when replacing the bearing plate to avoid
damaging - the seal. Remove the shim stock as soon
as the plate,is in place. .
Engines equipped with some types of reduction gear
assemblies do not use the rear o i l seal. The reduction
.gear assembly is oiled directly from the engine crank-
case. Refer to the instructions screened on the case
of the reduction gear assembly.
CYLINDER
The cylinder wears very l i t t l e in normal service. I f ,
through improper lubrication or accident, the cylinder
w a l l should become scored or worn badly, the cylinder
may be rebored and honed to accommodate a new piston
and ring set of the available oversizes. Pistons are
available in .005", .010", .020", . 0 3 0 " and . 0 4 0 "
oversize. Piston rings are available in .010", . 0 2 0 " ,
. 0 3 0 " and . 0 4 0 " oversize. Use standard size rings
on a .005" oversize piston. I f the cylinder is not being
installed, remove any ridge which may have become
formed at the top of piston ring travel in the cylinder
bore. Engine might be fitted at the factory with a .005 "
oversize piston and are so indicated by a letter E
following the engine- serial number stamped on the
cylinder block and on the unit nameplate.
U s e h e a v y f i b e r or
cup g r e a s e in s p a c e
b e t w e e n s e a l s to
i m p r o v e s e a l
R E A R B E A R I N G P L A T E
G E A R C O V E R
O I L S E A L
A877
G E A R
M O U N T I N G F A C E
O F G E A R C O V E R
T H I S . S U R F A C E S H O U L D
B E C L E A N E D O F A L L
O L D S E A L I N G C O M -
P O U N D B E F O R E . I N S T A L -
L I N G S E A L .
C O V E R O I L S E A L -
T H I S S U R F A C E S H O U L D
B E C L E A N E D O F A L L
O L D S E A L I N G C O M -
P O U N D B E F O R E I N S T A L -
L I N G S E A L .
D R I V E OR PRESS O I L
S E A L T O S H O U L D E R
O F T H E P L A T E B O R E
R E A R B E A R I N G P L A T E
O I L S E A L
F I G U R E 5 7 . G E A R C O V E R A N D R E A R B E A R I N G P L A T E O I L S E A L S
37