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9-44
E N G I N ES-8-CY 1 IN D ER
(2)
Deglazing of the cylinder walls may be done
us-
ing a cylinder surfacing hone, Tool C-3501, equipped
with 280 grit stones (Tool C-3501-3810). If the cylinder
bore is straight and round, 20-60 strokes depending
on the bore condition will be sufficient to provide a
satisfactory surface. Inspect cylinder walls after each
20 strokes. Use honing oil (2-3501-3880
or a light hon-
ing oil available from major oil distributors. Do not
use engine or transmission oil, mineral spirits or ker-
osene.
(3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marks intersect at 60°, the cross hatch
angIe is most satisfactory for proper seating of rings
(See Figure 101).
(4)
After honing, it is necessary that the block be
cleaned again to remove all traces of abrasives.
CAUTION: Be sure all abrasives are removed from
engine parts after honing. It
is
recommended that
a solution of soap and water be used with a brush
and the parts then thoroughly dried. The bore can
be considered clean when it can be wiped clean
with a white cloth and cloth remains clean. Oil
bores after cleaning to prevent rusting.
PISTON AND RINGS
The pistons are cam ground so that the diameter at
the pin boss is less than its diameter across the thrust
face. This allows for expansion under normal operat-
ing conditions. Under operating temperatures, expan-
sion forces the pin bosses away from each other, thus,
causing the piston to assume a more nearly round
shape. It is important that pistons be checked for
taper and elliptical shape before they are fitted into
the cylinder bore (See Figs. 102 and 103).
Finished Pistons
All pistons are machined to the same weight in
V- 8
PISTON
!
,027
T O
,035
IN. LESS
THE ELLIPTICAL SHAPE
OF
THE PISTON SKIRT SHOULD
BE
,009
T O
.010 IN.
LESS
A T D I A M E T E R ( A ) T H A N
A C R O S S T H E T H R U S T
PISTON SKIRT
DIAMETERS AT
(Cl
A N D (D)
C A N BE EQUAL
O R
H A V E A
?0.0005
IN. TAPER IN
F A C E S A T DIAMETER-(B).
64x644
A
THE ELLIPTICAL SHAPE OF
THE PISTON SKIRT SHOULD
B E .010 TO .012 IN. LESS AT
DIAMETER (A) THAN ACROSS
THE THRUST FACES AT DIAM-
ETER
( 6 ) . MEASUREMENT
IS MADE '/e IN. BELOW
LOWER RING GROOVE
DIAMETERS AT (C) AND (D)
CAN BE EQUAL OR DIAMETER
AT (D) CAN B E .0015 IN.
GREATER THAN (C)
N Y 220A
Fig. 103-Piston
Measurements
1361,383
&
426 Cubic Inch)
grams, regardless of oversize to maintain piston bal-
ance. For cylinder bores which have been honed or
rebored, pistons are available in standard and the fol-
lowing oversizes: .005, .020,
.040
inch.
273
and
318 Cubic Inch
Engine
Fitting Pistons
Piston fitting should be done at normal room tem-
perature, 70". Use a spring scale and a strip of
Y 2
inch wide feeler stock .0015 inch thickness. The feel-
er stock should be long enough to extend into the cyl-
inder bore to the full length of the piston travel.
The
cylinder bore and piston must be clean.
(1) Coat the cylinder bore lightly with SAE 1OW
engine oil. Insert the piston in the bore upside down
with the feeler stock between the thrust face of the
piston and the cylinder wall.
Fig. 102-Piston
Measurements
1273
8
318 Cubic Inch)
Fig. 104-Fitting
Piston in Cylinder Bore
1273-318 Cubic InchJ
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