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53
E N G I N E — S e r v i c e I n f o r m a t i o n
4.
A s s e m b l y o f C o n n e c t i n g R o d s
W h e n assembling c o n n e c t i n g rods to the crankshaft,
be
sure that the n u m b e r s on the rods are t o w a r d s the b o t t o m o l
the engine and t h a t they correspond w i t h the numbers of the
caps.
T h e chamfered side of the bearing s h o u l d be next to
the crankshaft cheek.
T h e pistons s h o u l d also be assembled o n the rods w i t h the
piston p i n l o c k i n g screw o n the same side of the rod as the
flange.
5.
F i t t i n g P i s t o n P i n s
W h e n pressing pins i n t o o r o u t of p i s t o n , a l w a y s place
l o c k i n g screw side of p i s t o n d o w n to p r e v e n t forcing piston o u t
of round.
B u r n i s h piston p i n bushings u s i n g tool N o . H M J - 2 5 0 - 2 .
F i t pins d r y .
P i n s s h o u l d t u r n freely in bushings w i t h no per-
ceptible p l a y or looseness.
In p r o d u c t i o n , p i s t o n pins are a tight press fit in the lock
screw side of the p i s t o n .
It is n o t expected t h a t this press fit
will a l w a y s be d u p l i c a t e d i n service a n d s n u g push fit s h o u l d
be satisfactory.
6.
C o n n e c t i n g R o d C l e a r a n c e
C h e c k clearance i n c o n n e c t i n g rod bearing w i t h d i a l i n d i -
cator ( T o o l N o . H M - 1 9 6 - B ) a n d holder.
D o
not a t t e m p t t o adjust
c o n n e c t i n g rod bearings.
II
clearance exceeds l i m i t s g i v e n i n s t a l l new o r rebabbited rod
a n d return o l d one t o factory for exchange. N o credit w i l l
be allowed o n rods if cap or r o d has been dressed d o w n .
T h e same c o n d i t i o n s govern the return of rods w h i c h have
been rebabbited b y outside repair shops a n d w h i c h are d a m -
aged or bear p u n c h o r file m a r k s used for identification pur-
poses.
M e c h a n i c s s h o u l d a t t a c h
n u m b e r e d
metal tags to
the rods as they are removed from the engine, o r lay t h e m in
trays in the right order to identify t h e m instead of m a r k i n g
t h e m w i t h a p u n c h o r file.
7.
R e m o v i n g a n d I n s t a l l i n g P i s t o n P i n B u s h i n g s
T h e r e m o v a l a n d i n s t a l l a t i o n of the s p l i t - t y p e piston p i n
bushings requires the use of special tools.
A k i t of tools
( T o o l N o . H M J - 2 5 0 ) is furnished for this purpose.
T h e bushing s h o u l d be removed in a n arbor press a n d s h o u l d
be started b y g i v i n g the handle of the press a sudden j e r k
instead of a steady p u l l .
A f t e r the b u s h i n g is started it w i l l
move o u t quite freely.
T h e connecting rod should then be
thoroughly cleaned o f a l l chips a n d d i r t .
T h e b u s h i n g c a n n o t be pressed into the c o n n e c t i n g r o d in
the usual manner.
Instead, it is pressed in the rod a n d ex-
panded w i t h a n e x p a n d i n g b a r t o press the bronze into v e r y
close contact w i t h the steel rod.
It is then burnished, l e a v i n g
a long hard-wearing bearing surface.
T o i n s t a l l a p i s t o n p i n b u s h i n g , proceed as follows:
(1)
Install the b u s h i n g in the side of the connecting rod
h a v i n g the large chamfer in the bearing for the crank p i n .
M a k e sure t h a t the o i l hole i n the b u s h i n g is i n line w i t h the
oil hole in the c o n n e c t i n g rod a n d the split is at right angles
to the .length of the rod.
(2)
Press b u s h i n g i n r o d u s i n g b u s h i n g replacer, tool N o .
H M J - 2 5 0 - 3 .
U s e a 2 or 3 t o n bench arbor press.
(3)
E x p a n d the b u s h i n g w i t h E x p a n d i n g B a r ( t o o l N o .
H M J - 2 5 0 - 1 ) .
I f the b u s h i n g protrudes t h r o u g h the c o n n e c t i n g
rod, file it flush w i t h the rod before b u r n i s h i n g .
(4)
B u r n i s h b u s h i n g b y passing b u r n i s h i n g tool N o H M J -
250-2 t h r o u g h the b u s h i n g .
W h e n e x p a n d i n g or b u r n i s h i n g a
bushing, use a h e a v i e r bench arbor press of about 4 tons
capacity.
Use kerosene as a l u b r i c a n t when expanding a n d b u r n i s h i n g
the b u s h i n g .
If the bushing moves d u r i n g the b u r n i s h i n g process, it is
too loose a n d another one s h o u l d be used.
If the proper clearance between the piston pin a n d
the
bushing is not secured after the b u r n i s h i n g tool is passed
t h r o u g h
the b u s h i n g , the b u r n i s h i n g operation should
be
repeated to increase the size of the piston p i n hole.
T h e press plate ( T o o l N o . H M J - 2 5 0 - 4 ) s h o u l d be used for
e x p a n d i n g a n d b u r n i s h i n g the b u s h i n g .
T h i s plate has t w o
holes—one
w h i c h
is used
for assembling, e x p a n d i n g
a n d
b u r n i s h i n g and the o t h e r for r e m o v i n g the bushing.
A f t e r i n s t a l l i n g the b u s h i n g the p a r t s should be thoroughly
cleaned a n d the o i l passages b l o w n o u t w i t h air to remove
chips and d i r t .
8.
M a i n B e a r i n g C l e a r a n c e
Use d i a l i n d i c a t o r a n d special fixture ( T o o l N o . H M 055 301
for c h e c k i n g b e a r i n g clearances.
If bearings are found to be
worn b e y o n d specified l i m i t s they s h o u l d be replaced.
R e -
placement bearings are furnished to exact, size a n d do not
require reaming or s c r a p i n g .
N o s h i m s or liners are used o n
the m a i n bearings a n d no a t t e m p t s h o u l d be made to take
t h e m up if w o r n .
A l w a y s install new wooden plugs in grooves in sides of rear
m a i n bearing c a p to p r e v e n t o i l leaks a r o u n d the cap.
9.
C l e a n i n g O i l F i l t e r o n 3 7 0 - B a n d 4 5 2 - B
A C u n o d i s c - t y p e self-cleaning o i l filter is used o n the 370-B
a n d 452-B cars.
T h e o i l , in c i r c u l a t i n g t h r o u g h the
filter,
passes between
t h i n r o t a t i n g discs, s t a c k e d one u p o n another, a n d separated a
few t h o u s a n d t h s of a n i n c h b y a series of t h i n stationary plates.
The filtering discs are m o u n t e d o n a shaft w h i c h extends above
the filter a n d is connected t o the starter pedal in such a w a y
t h a t the discs are rotated a p a r t i a l t u r n each time the starter
pedal is depressed.
W h e n the filtering discs are rotated the a c c u m u l a t e d sedi-
ment is scraped off b y the s t a t i o n a r y plates a n d falls to the
b o t t o m of the t a n k .
T h e o n l y a t t e n t i o n required is the d r a i n i n g of the t a n k c v e r v
6000 miles.
10.
P i s t o n C l e a r a n c e s
Use T o o l H M 119929, w i t h a .0025 i n . feeler r i b b o n , .½ i n .
w i d e a n d a s p r i n g scale,
for c h e c k i n g piston
clearances.
P i s t o n must n o t be o v e r .002 i n . o u t of round.
Clearances
s h o u l d be measured between s k i r t of p i s t o n and c y l i n d e r wall
half w a y between w r i s t p i n holes w i t h piston half w a y d o w n
on its stroke a n d w r i s t p i n hole p a r a l l e l w i t h crankshaft.
B o t h
p i s t o n a n d c y l i n d e r w a l l s s h o u l d be clean a n d free from o i l .
If the clearance is correct, a p u l l of 4. to 9 lbs o n 3 4 5 - B a n d
3 5 5 - B engines a n d 6 to 9 lbs o n 3 7 0 - B a n d 4 5 2 - B engines w i l l
be necessary to w i t h d r a w the feeler.
11.
B u r n i n g C a r b o n o n 3 7 0 - B aricl 4 5 2 - B C a r s
W h i l e the most satisfactory w a y of r e m o v i n g carbon from
a u t o m o b i l e engines
is b y s c r a p i n g , the
labor i n v o l v e d i n
r e m o v i n g the c y l i n d e r heads w i t h the o v e r h e a d v a l v e m e c h a n -
ism o n the V - 1 2 a n d V - 1 6 engines sometimes renders scraping
i m p r a c t i c a b l e .
B u r n i n g the c a r b o n , if properly done, w i l l
g i v e good results o n these engines at a m u c h lower cost to
the owner.
If this m e t h o d is used, the c a r b o n s h o u l d be allowed t o
b u r n s l o w l y to o b t a i n the best possible results.
Q u i c k b u r n i n g
w i l l do o n l y a p a r t i a l j o b .
T h e rate of c o m b u s t i o n can be
c o n t r o l l e d b y the proper r e g u l a t i o n of the o x y g e n s u p p l y t o
the c o m b u s t i o n c h a m b e r .
W h i l e the c a r b o n is being b u r n e d , p a r t i c u l a r care must be
t a k e n to prevent i n j u r y either to the valves or to the external
fittings
on the engine.
T h e proper procedure is as follows:
R e m o v e the s p a r k p l u g wires a n d d i s t r i b u t o r cover, or use
a suitable asbestos c o v e r plate to protect t h e m d u r i n g the
b u r n i n g o p e r a t i o n .
R e m o v e a l l spark plugs.
T h e next step is a m a t t e r of extreme importance, t h a t is,
to be sure the valves are b o t h closed o n the c y l i n d e r being
b u r n e d .
If the valves are not closed, they are very likely to
be overheated, c a u s i n g t h e m to w a r p .
T h e o n l y p o s i t i v e way to m a k e sure the valves are closed is
to use a test, l i g h t a n d c r a n k the engine to the firing point o n
t h a t c y l i n d e r .
See F i g . 4, P l a t e 30.
A l l o w the c a r b o n to b u r n s l o w l y u n t i l it has all been burned.
B u r n out a l l of the left h a n d c y l i n d e r s first, in the order in
w h i c h they fire: then b u r n the right h a n d c y l i n d e r s .
The
firing order, is, of course, i n d i c a t e d o n the d i s t r i b u t o r cover.
R e m o v a l of c a r b o n in the V - 8 engines s h o u l d be done b y
scrapirig as in the past.
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