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GROUP 21
ENGINE
DESCRI PTION
CYLINDER BLOCK
The
cyl1
inder
block (43,
Ildustration
2 A)
is
made of
specia,1
cast
,
i ,ron ond is cast in o single unit. The
cylinder bores,
which
are surrounded by
coo,
l ing
jackets,
are
machined
directly
in
,
t he
block.
The
ol
i l
-
ways in the block are orranged so that the oil filter,
which
is
of the fu
-
I I
-How type,
,
i s
-
di rectly attached to
the .right-hand
side
of the block.
CYLINDER HEAD AND VALVES
The cylinder head
(37) is
seCU'red to
-
t he block by
means of bolts.
A~I
the
combus~ion
chambers are
machined throughO'utand
have
separa-
t e
inl,
e t and
exhaust ,ports, one for each
vallve
.
The valves (6 and 9,
IHustra~ion
2 A) which are fitPed
suspended
in
,
t he cyl,inder head,
are
made of
special
stee-
I and
arecarried
in
repbceable guides. The
va,lve
stems
are chrome,d.
The valve
collet is
provided
with three
lands and the
va-
I ve
with
corresponding grooves, which hold the
valve
but
also
make
suir~able
rotation
possihle.
(Compare
with Fig. 2-22.)
The
valves
are
provided
with
va,lve
gUI
ide rubber sea Is, which are mounted on
the guides.
Viewed in order from the front, the va,lves are placed:
intake,
-
e xhaust, intake, exhaust, and so on.
The cooling jackets are designed so
th·a1
t the air
around the spark plugs is also coolied. Water distri-
bution is by means of a pipe, the waler being directed
towards the warmest par,ts of the
eng-
i ne.
CRANKSHAFT AND BEARINGS
The crankshcdit is made of steeland has ground, case-
hardened bearing journa/Is. It is carnie,d in seven moin
bearings, the rem flange hearing of which also
functions as a pilot
bea'
r ing
axial,ly. There are drilled
oilways in the crankshant for the
lubrica1
t ing oil.
A gear mounted on the front of the crankshaft drives
the
timing
gears through a sp,lined joint. The crank-
shaft end projeding from :the gem wheel has a
pOllygon
prohl,
e . Mounted
on
,
t his pin is the polygon
hub for the
flywhe-
e l dampec
80th the
ma-
in-beaning and the hig-end beafiing sheiis,
which are reptlaceahle, consist of a stee·1 backing with
indium-pla/
t e leadbronze bearing
mel
t a"- 80th front
and rear crankshaft oil seals are rubber-lip type seals
with metal frame.
CAMSHAFT AND VALVE TAPPETS
The
camsha~t
(61)
,
i s
made
of
special -alloy east
iron
and
.
has case-hardened
cams.
It
,
i s
-
driv-
e n from the
crankshaft
throug,h
a
g-
e
-
ar train
which has
a ratio of
1
:2.
The camshafit is cQrried in four bearings, all
of
which have the same diameter. Camshaft axial
loca-
tion
is
maint-
ained by
me'
a ns of a bronze
ax'
i al washer
located
at the front end of
·
t he
camshaft.
Axia/
1
play
is determined by a space'r ring behind the camshaft
gear. The valve tappets (41) are adUrated directly by
the camshaft. They a,re locat'e'd
in holes in
the block
above
-
t he camshaft and transfer
mov,
e ment to the
va-
Ives
by means of push rods and
rocker
arms. There
are no
inspedion
covers for the valve tappets since
they ore acoessihle
afi
t er
the cylinder
head
has been
removed.
CONNECTING
RODS,
PISTONS AND PISTON RINGS
The connecting rods (55) are made of drop-forged
steel and are provided with a precision-machined
bush whi'ch aots as
a
bearing for the
gudg/
e on
pin
.
The big-end
bea-
ring sheHs are
precis-
ion-manufaotured
and are
replaceahle.
The pistons
(62)
are made of light-alloy and have
two
compression rings ·and one oi·1 scraper
-
r ing.
The upper
compression ring is chromed in order to reduce cy-
I'inder wear.
The gudgeon pin (59) has a
f.loating
fitin both the
piston and conneding
rod.
The
aX1
i.al movement of
the
gudgeon pin is
rl- i,mi,
t ed hy circlips in the gudgeon
pin hole.
FLYWHEEL DAMPER
The flywheel damper (76) is of the rubber type. The
hub is
joint-
e d to the crankshaft by means of a poly-
gon jOlint. The flywheel mass
-
is
j·ouma,lr
le·d on the hub
through a ,rubbersuspension. The gmduartion for the
igni,
t ion setting
i'
s
ma,rked
on the flywheel damper.
INTAKE AND EXHAUST MANIFOLDS
The intake and
e~haust
manifol·ds, the material of
wh,ich
,
i s of
nodu,l-
a -r i'ron, are cast
-
on to a branch pipe.
They have been designed with a vi·ew
to the
exhaust
emission controi system, with
prehea1
t ing chamber
wherein the temperature of the fuel-air mixlure is
mised by the heat from >the exhaust
pOlr-
t s.
2:7
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