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case
lo
prevent
oil
from
leaking along this
part
of
crankshart.
The
oil seal
is
doweled
to
take
a
given
position.
lUlling gears
Hel
ical
gcars
made
o
f
hJgh carbon steei
are
used to drive
injection pump
and camshaft
from crankshaft through
an if.ller. The teeth of thest
gears
il
re
fll1ished
by shaving
for
increased
durability
and
.high
milchining
accuracy
.
Because
of
hell-cal
mesh,
tl1ese
gears
run
quietly and
aSSllre
acc
ura te
llrriing
attion.
l
Cam,hart
1
,C"rru.haft
gear
~N
o
.
of lea
In:
38}
2'·ldler
~No.
of
ItI<i!th
:
43)
J-C'lnksn.aft
gear (No. of
tel!lTh:
19)
4
·l
njtc
tion
pump geM
(No
.
o
f
te-e,h
:
3BJ
Timing
gear
configuration
The -camshaft is
a
hiSh carbon steel in
material,
and its
cam surfaces
are
chill
hardened.
Tno
rron
l
journal
has an oil hole, through which
the
lube oil under pressure flows
from
crankcase toward the
valve mechanism over the cylinder head
.
A part of this
iI
lubricales
the
thrust
face
of camshaft.
Tappets
The lapp.1 is
of
fl.1 type
and
>hoped
pal.~ke
to
admit
the
push fod into
its
hollow
.
It
is
cast
iron
in
m.a.terial;
its
cam·riding
face
is: hardened
by
chilling.
This
design
provides a lightweight tappet, resi-S1ant to wear and
strong
and Ihu, ,ui«d to high-speed operation. All
tappets
,
regardless
of
whether they
oro
for
intake v,lves
or
exhaust
valves,
art idenheal
and,
therefore
I
idenlified
by the
~e
part number
.
The
axiS
of the push rod i,
sUghtly
offset
from Ihe eenle,
of the cam
.
This offset
is
calculated
10
cause the tappet
to
rotate during
ope
ration and thus to
prevent
its
cam·
riding face
fr
om
wtaring
unevenly.
CONSTRUCTION AND FUNCTION
:
..•
~
-{2
'I
' -Valve p
uih
rod
4
-Carml\3fl
2·TaPP8t
A·Am
o
unt
of of"et
3-CrankcosCl
Tappet
-
Cross
sectIon
Val"" push rods
Made
rrom carbon·steel
pipe stock, the purn
rods
h"
•
steel
ball
welded
to
its
boltom
end
an'd a caved-in
piece
welded
t
o
iu
top end
.
By
Ihe ' leel bail
,
Ihe
push
lods
stands
on
the-
spherical
seat provided in the tappet and ,
by the cavcd·m top e.nd,
it
bears againSt the
adjusting
screw tlueaded in
the rocker arm
.
These
contacting
ends
are hardened
hy carbu rizalion.
Valv.
timing
and
valve Ia<h
Valvo
laID
IS
pre,cribed
to be 0 .25
mm
(O,0()98 In.)
(cold)
fOI
both Inlake .nd
exh.
u,t
vah'es,
and Ihe
valve
mechanism is
timed
[0
actuate the
valve as follows:
INTAKE VALSES
open at
30' B,T,D,C,
close
al
SO'
A,B
,D,C,
EXHAUST
VALVES
open at 74'
B.B.D,C.
close
al
30'
A.
T
.D,C,
Ex
n{juH
s'rrok~
T.D.C
.
30'
lY
:::--;--....
B,O.C.
w
Valve timing diagram
Intake
:rlro,ke
21
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