1980 SKODA 120L engine

ENGINE
CYLINDER HEAD ASSEMBLY
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2.2-2.3
threods. Fill the etrgine with oil ond the cooling
systenr with on ontifreeze, ond
bleed them.
2.3 REASSEMBLING THE ENGINE
The reossembly procedure depends
on the
extent to which the engine hos been
dis-
rnontled. For better understonditrg, o
reossembly
of o conrpletely disnrontled
engine is described
in the following
porogrophs.
lnspection of
Cylinder Block
1. Clomp the thoroughly cleoned
cylinder
block into the MP 9-101 stond with the engine
corrier type MP 1-101 ond check it for complete-
ness -
see Chopter 2.6. Fit the
block with its
lugs on the engine corrier pins
ond use the side
bolt for ltolding it down.
DK 1188
Fig.2311- Cylinder Block Fostened on the
Assenrbly Stond by lVleons of the MP 1-10-l
Corrier
2. Rernove the pressure
relief volve, moke
sure thot the boll contoct {oces ore cleon,
ond
refit the cleoned volve. Forr
f itting o new volve
see Chopter 2.6.
3. Remove the cronkshoft beoring
covers ond
tlre i;ylinder block reor cover.
To Refit the Cronkshoft
4. Force the beoring shell lrolves with the
fingers into the cronkshoft beoring bores so thot
the shell lip snops home into the slot (cut-out)
in the block ond so thot the shells do not pro'
trude over the beoring surfoces for the beoring
covers, ond lubricote them with engine oil. Be
r;ure to fit shells motching the cronkshoft
i":urnols -
see Chopter 2.7.
5. Slip the oiled guide
ring on the cronkshcft
"vith oil grooves
pointing
toword the cronkshoft
'.veb ond {it the cronkshoft with the pressed-on
boll beoring (see
Chopter 2.7)
into the shell. 6.
Inscrt the
beoring shell
holf ir-rto
the cover
of the beoring No.-l
os described in
porogroph
4,
ond fit the cover with the
recess for the guide
ring turned outword. Proceeding from
the front
of lhe block, slip
on the next guide ring with
the oil grooves pointing
owoy from the block so
thot itJ
lip engoges ogoin into
the slot in the
cover. Coot the ring
with oil ond slip on the
thrust ring. Fit the MP -1'112
thrust collor on the
cronkshofi ond
tighten the
beoring slightly
using the belt
PrrlleY bolt.
7. Instoll the next
two beorirrg covers
corl'l'
plete with beoring shells
ond lightly
tighten l.he
cover nuts.
Press the cork
seol
into the
reo'r
cover moking
sure thot it
f its the groove
snugly
ond slightly bverlops the lower
seoting surfoce'
Before titting the cork seols,
compress them
for
o while in o vice to distort them. Insert the
distorted seols in the grooves
or gops between
the cover qnd
the cylinder block
where they
will expond onci provide
for perfect seoling.
lnsert tob woshers under
the nuts of the
beoring covers
ond while tightening the rruts
check their correct position so os
to enoble
o subsequent correct locking
of the nuts.
Fig.2.312 -
Meosuring Cronkshoft Ploy
1 -
Thrust collor, type
MP 1 112
2 -
Diol indicotor in o
speciolly mode yoke
8. Rotote the cronkshoft severol times ond
using o mollet top the covers ond both shoft
ends to ensure o correct bedding
of the covers
ond cronkshoft guide rings.
9. Tighten the belt pulley nut
to clomp the
thrust ring, ond
rotote ond force
off
the cronk-
shoft to
check its ploy. The
cronkshoft must
be
free to rotote but
without ony
noticeoble ploy.
lf there is o noticeoble ploy, recheck
its volue
ond odiust it by replocing the guide ring with
o new one. The
moximum ploy
should not ex-
ceed 0.10 mm, the recommended minimum ploy
being 0.04 mm. 10.
F
speciol
end onr Drive
suchr o
be turnr
cover. I
ever, tf
the cyl
speciol note in
11. Ti
the tigh
in the
covers. hoving
does no
must ro
Then lo,
woshers
ond nut
To Refil
12. R
greose i
it with i
o flywhr
engine,
with rec
under tt
Chopter
bending
shoft og
powl ins
For flyw
Fig.2.3l3
Using thr
Screw
holes, for
con be ur
further o1
the hondr
30

Fig.2.3/6
-
Position of Cylinder Liners,
Pistons
ond Connecting Rods in Engine
1 -
Proiectlon of cylinder liners
obove the top
foce of the cylinder block (0.125 -
0.155 mm)
2 -
Connecting rod splosh hole
'3
- Arrow on the piston
heod pointlng
toword
the comshoft
4 -
Comshoft
Fig.2.317 -
Pilot Ring
for Piston Rings
Dimensions of pilot
ring to motch cylinder
liner diometer:
dio. 68 D:68 H 7
dio. 68.25 D :68.25
H 7
dio. 68.50 D :68.50
H 7
dia. 72 D:72 H7 14.
Hoving fitted the piston
rings ond con-
nectlng rods on the pistons,
turn the piston
ring
gops so thot they ore stoggered
through 120o.
Coot the entire surfoce of the piston
with the
fitted rings with oll ond insert the pistons
ossembled with the connecting rods into the
liners in the sequence of the corresponding
numbers of cylinders ond connecting rods. Moke
sure thot the
orrow in the piston
heod points
toword the morking
of the cylinder liners, l.e.
toward the comshoft, ofter the ossembly with
the cylinder block. This
is importont in thot it
does owoy with odditionol turning of the pis-
tons in the liner ond o posslble
displocement
of the piston
ring gops.
Smeor the top surfoce of the cylinder block
with point
or o seoling
compound before
instol-
ling the liners with the pistons
ond connectlng
rods into the cylinders in the order of their
numbering. It is odvisoble to prepore
o sheet sleeve or
o pilot
ring occording to Fig. 2.317
to com-
press the piston
rings when fitting
the piston
Into the cylinder liners. Force the piston
into
the sleeve or pilot
ring so
thot the piston
heod
is flush with its edge or protrudes
sllghtly
over it, locote the piston
on the liner, ond then
force down the piston
through the sleeve or
pilot ring into the liner.
15. Ploce suitoble ouxiliory devices over two
holes for
cylinder heod bolts, for exomple
lorge-diometer woshers, ond screw them down
Fig. 2.3/8 -
Fitting Piston into
Cylinder Liner
Using the Pilot Rlng
1 -
pilot ring
2 -
cylinder liner
32

primory
feed to the distributor coincides with
the connecting line of the
distributor centre
line ond the first cylinder
heod
bolt os
per
Fig.2.3l10. Secure the distributor in this pos-
ition by lightly tightenning the tie-bolt ond
remove the timing geor
cover from the cylinder
block. The used type of distributor is described
in Chopter 13.5.
Fig.2.3l10 -
Position of Distributor on Engine
-l - screw of primory power
feed
2 -
cylinder heod bolt
3 -
index line rnorking the position
of the
distributor ornr when cvlinder No. 1 f ires
24. Coot with oil the moting
surfoces of the
timing geor cover ond the cylinder
block, locote
the cover gosket
on the block,
oil the timing
choin ond the comshott worm geor.
Remove the
f lywheel powl
ond rotote the
cronkshoft through
360o so
os to bring tlre pistons
of the cylinders
No. 1 ond 4 to their TDC position
ogoin. This
position corresponds opproximotely
to the volve
geor position
when the cylinder No. 1 f ires (the
tips of the coms of
cylinder No. 1 ore turned
downword, owoy from
the engine). Lock the
cronkshoft in position by refitting ond tight-
ening the flywheel powl.
25. Turn
the distributor orm in the direction
of the
screw (1) in occordonce with Fig. 2.3110,
hold it down with the
finger in this position,
ond ref it the timing geor
cover on the cylinder
block. By sliding the worm geor
of the distribu-
tor drive into the comshoft worm geor,
the orm
is turned to coincide with the timing
mork for
cylinder No. 1
on the distributor housing. lf
there is no coincidence of the orm ond timing
mork, od just
the position
of the orm by
slightly
rototing the distributor.
lf the
misolignment of the distributor
ornr
ond the timinq
mork of the
cvlinder
No'1 is so greot
thot it connot be corrected
by rototing
the distributor, remove
the timing geor
cover,
rotote the distributor slightly ond repeot
the
entire procedure
of refitting the timing geor
cover. 26. Smeor the protruding
end of the cronk-
shoft ond the outer shoft end (stem)
of the
belt
pulley with oil, f
it the belt pulley,
the nespective
wosher, ond tighten the bolt. Bolt the
PumP
suction stroiner tothe cronkshoft centre beoring
ond use o spring
wosher under the bolt heod.
27. Bolt down the timing geor
cover using
spring woshers ond
cheese-heod bolts
(exclus-
ively) cnd f inolly fosten the timing geor
cover
in such o position
thot the contoct breoker
points open before the crronkshoft with
the con-
necting rod ond piston
hos ottoined the top
deod centre (TDC)
position (see
the lgnition
Timing Toble in Chopter 15.3).
For checking the ignition odvonce, on electric
power supply is required with o bulb connected
in o circuit with the distributor. this
circuit
being interrupted by the oction of the contoct
breoker. An odopted conventionol torch with o
metol
iocket con be
used with odvontoge for this
purpose. Remove the flywheel powl ond
set the re-
quired ignition odvonce by turning the cronk-
shoft with o screw'driver inserted into
the geor
ring ond propped ogoinst the cylinder block
f longe. Rotote the shof t onticlockwise o bit
more thon necessory ond
bock it off so os to
odiust the bocklosh of the timing geors
ond the
distributor drive geors.
oK 6ls
Fi9.2.3111- Lomp for Checking the Opening
of Contoct Breoker Points
-1 - torch complete with dry cell ond bulb
2 -
leod with olligotor clomp
3 -
botterv cell
4 -
torch coo
5 -
contoct spring
6 -
insuloting plote
7 -
electricol-contoct connection of the leod
with the
drv cell Con
using
torch.
the br
slowly
indico
A corr
is not
timing 28.L
beorin
Then f
while
oil sun
the thr
the tyl
see Cl.
shri n ks
of the
woter
move i
ively.
To Fit
Toppetr
25. r
remove
positior
sure thr
cylinder
cylinder nuts. F<
first bo
woteir p
oir clec
finol ti1
2.16.
Ploin
heod bo
which t
woshers
no wosl
heod bo
cy I i nder
the outs
hove to
of the rc
Tighte
broce or,
30. Sc
thermom
into the
cosing o
ofter ho
Use spri
thermost
cooted g
with the
with the
The th
should br
34

ilil
ll
I
Z,l
spring woshers under the pump
fostening nuts.
36. lnstoll the oil filter -
see Oil Filter in
Chopter 15.3.
37. Bolt the brocket ond the reloy lever
of the
occelerotor linkoge to the intoke monifold, Use
spring woshers to lock the bolts in position.
38. Locote the corburettor gosket, sheet
guord, onother gosket,
the insuloting wosher,
ond o third gosket (oltogether
three goskets
of
the some type) on the intoke monifold inlet
socket, instoll the corburettor,
ond tighten
it
down with nuts.
On 105 ond 120 l- engines, the sheet guord
must be fitted to the intoke monifold inlet
socket with o throttling spider, while 120 LS
engines must hove the possoge
unobstructed.
39. Smeor the boll pins
of the linkoge
ond
corburettor lever with greose
contoining molyb-
denum disulphide
ond mount on them the oc-
celerotor link (tie-rod).
Hold the link in pliers
ond slip securing clips over the heods.
Hook o spring on the shonk of the reloy
link-
oge boll pin
ond on the rib of the forehousing
on the corburettor.
40. Screw down the vocuum
control pipe
on
the corburettor (using
double-sided seoling
rings) ond slip on the rubber
hose connecting
the pipe
with the distributor vocuum control
unit. Secure the pipe
by bending the clip under
the nut of the intoke ond exhoust monifold.
To Refit Alternotor
41. Attoch the olternotor
brocket to the side
of the cylinder block while putting
ploin
woshers under
the nuts. Mount the olternotor
holder together with the engine mounting lug
on the bolt of the timing geor
cover ond the
front lug of the cylinder block.
Use self-locking
nuts for the bolts f ostening the olternotor
holder. Lock
the lower bolt of the lug by meons
of o spring wosher
ond nut. Using onother bolt,
bolt together the lug ond the brocket. lnsert
the tie-bolt from
the side
of the lug, slip on
o ploin
wosher ond tighten the nut. Fit the
short-circuit strip on the bolt ond lock it in
o position
porollel
with the olternotor brocket
by screwing
down the respective nut with
o ploin
wosher.
42. Put the olternotor into the holder,
ttrreod
in the bolt, ond screw down the nut with o ploin
wosher without tightening. Without tightening
the self-locking
nut, bolt the strut into the
brocket on the cylinder heod. Swing the olter-
notor toword the engine, fit
the V-belt ond,
while tensioning it, connect the olternotor with
the strut using o bolt, spring wosher ond nut.
At the some time, tighten the nut of the bolt
holding down the olternotor
in the
holder ond
the nut of the bolt connecting the strut with
the holder. For the belt slock odiustment see
Chopter 15.3. 43.
Fosten the second
engine mounting lug
using nuts with spring woshers.
To Fit Cylinder Heod, Air
Cleoner,
ond Sporking Plugs
44. Fit the cylinder heod
with cemented.on
gosket on the cylinder block ofter hoving slip-
ped o seoling ring ond o wosher on eoch bolt,
the some os in the cose of the push-rod
cover.
In oddition, fit the fuel pipe
holder on the reor
bolt ond hold it down by slightly tightening the
nut.
45. Fit the oir cleoner in position
ond fosten
it to the corburettor with o bolt using o seoling
ring ond wosher. Put o spring wosher
under the
nut on the brocket
ond screw down the nut on
the bolt of the cover without ony wosher.
46. Threod the fuel hose through its holder
on the cylinder heod ond use clips to fosten it
to the corburettor ond pump.
Adiust the most
suitoble position of the hose by rototing
the
holder ond then tighten the nut.
47. Attoch hoses connecting the oir cleoner
with the corburettor ond the oil filler neck.
When preporing
the cc for driving in winter,
instoll the winter
oir-intoke tube (hose) -
for
detoiled instructions see Chopter 15.3 "Air
Cleoner -
Winter Operotion".
48. Screw in the sporking plugs
with seoling
iings ond fit the ignition cobles. For the re-
commended types of sporking plugs
see Chopter
13.7.
The outlet on the distributor cop morked with
o notch is intended for
the coble
to cylinder
No. 1. The
remoining outlets ore.to be counted
clockwise ond in direct
order from 1
to 4 ond
the cobles will be connected to sporking plugs
in the order of numbers cost on the cylinder
heod beside the recesses for sporking plugs.
Plug Screws ond Lubricotion
System
Accessories
49. Plug the oil sump with the conicol screw
plug with its
seoling ring. In the cose of on
engine without the oil cooler, plug
the oilwoy
on the timing geor
cover with o screw plug
with o seoling
ring, ond the oilwoy ot the reor
end of the cylinder block with o pressure
switch. lf the socket for screwing down the
pressure switch is missing, instoll o new socket
together with its respective seoling ring.
lf on oil cooler is provided,
hoses ond o press-
ure switch should be
connected to the oilwoys
occording to Chopter 11.9.
Put the oil dipstick
with the f itted rubber ring
in its ploce.
For the type of the dipstick see
Chopter 2.17.
50. Using spring
woshers with the bolts,
screw down the flywheel
guorcl
ofter removing
36

5. Use
the MP 1'105 puller
for removing
cylinder liners from the
block. Turn the centre
bolts of the
iig to expond
the
iig iows in the
cylinder liner (ot
the top flonge of the liner)
ond pull
out the liner by turning the vwench.
6. Before removing the comshoft, lift owoy
the volve toppets. lf o
removol of the cylinder
heod is not considered, releose
the boll pins
of
the rocker orms, lift cwoy the push
rods, remove
the si'de cover of the push
rods, ond withdrow
the volve toppets.
2.5 BRAKE TEST
AND ENGINE
LUBRICATION SYSTEM DIAGRAM
Broke Tcst In view of
the very specific chorocter of
the test, especiolly with
regord to the speciol
testing eguipment,we do not intend to describe
the test procedure, restricting ourselves to
men'
tioning only the moin volues which the test is
supposed to verify. Volues indicoted in the
diogroms ore oppli'
coble to o new engine or on engine ofter o top
overhoul, which hos been
correctly run'in
by
running for o period
of obout 50 hours (2,500
km
trovelled). lf the engine is tested under other
conditions, the meosured volues must opprooch
the diogrom volues conformobly with the mech-
onicol condition of the engine.
ln diogroms, peok
performonce
volues ore
indicoted os meosured in complionce with the
CSw (Czechoslovok
Stote Standords) ond DIN
,CsNr
kwrotN'
1{J
I
20
r5t0 (Deutsche
Ingenieur Normen), i.e. with
oll oc'
cessoires reducing the gross engine
horsepower
(woter pump,
olternotor, oir
cleoner, exhoust
silencer). The
effective horsepower con
vory
with respect to the diogrom volues
within
o toleronce limit of
minus 100/s.
Every engine ofter
o top overhoul or reploce'
ment of individuol ports
of the cronk mech'
onism hos to be run'in exoctly like o
new
engine. Do
not forget to
drow your
customer's
ottention to this foct!
'",ffi15
NM
300 t000 som
t/n{a
5000 l/rnrn csilr
kwuril'
50
i
ilii Fig.2.5l2
-
Power Output ond Fuel Consumption
Diogrom -
Skodo 120 L engine
1- 3 see Fig.2.5l1
5000 t/mrn
Fig.2.511- Power Output ond
Fuel Consttmption
Diogrom -
Skodo 150
S
engine
1 -
power output, 2 -
torque, 3 -
specif ic fuel
consumPtion
k/SAE: h. p.
(SAE) 1/min :
r.P.m. Fig.2.513
-
Power Output ond Fuel Cons
Diogrom -
Skodo 120
LS engine
I
38 1- 3 see
Fig.2.5l1

For the
instol lotion of the engine on the test
bench, we indicote the dimensions
of the en'
gine flonge ond flywheel. During broking, the
engine qnd
the engine oil must
be properly
cooled to preclude
exceeding the oPtimum
service conditions, i. e. woter temperoture
ofobout
80 to 90oC, ond oil temperoture of 12O"C
moximum -
see Chopter 2.5,
porogroph 51.
Engine Lubricotion
The inner lubricoting oil distribution system
is shown in Fig.2.5/5.
6 DK .r5+9 2.6
cYL
The cyl
mochined
the cronl
ports, forr
ore mode
B locks fo
72 mm di
I i ners.
Oilwoys, I
o) Befo
o new cyl
ossembled
blow thror"
b) Coot
pound or p
the oilwoy
c) Likev
into the e
pound or p,
of the
cyli
one (of
lo
limits indi
Ports) to er
d) Tighte
ot cylinder
under it.
e) Foster
the cop of
Fosten the
with o bolt
Fig.2.611 ond
1 -
choin gre
plug, 3 -
iniel
relief volve,
with cop, 6 -
inlet from o
ptug, I
9
8
7
5t
Fig.2.515 -
Engine Lubricotion Diognom
Skodo 120 LS
engine hos,
in oddition, on oil cooler incorporoted between the punrp
delivery
broncir on the timing geor
cover ond the moin oilwoy (see
Fi9.11.9)
srlctionstroiner,2-pump,3-pressurereliefvolve,4-moinoilwoy,5-oil filter,6-by-poss
hole, 7- oil pressure
switch, 8-pulsotingchomber, 9- rocker orms, 10-connecting rod
splosh hole, 11 -
choin splosh screw
4
2
4 t-
oil I
?
?
I
;
t

2.6-2.7
seot in the cylinder block using o copper or
oluminium rod.
Reconditioning Recesses for
Cylinder Liner
Flonges
Before ossembling o used
cylinder block,
inspect ond cleorr thoroughly the moting
sur-
foces of the recesses for
cylinder liner f
longes.
lf chemicol ogents (petrol,
etc.) foil
to hove
the required
effect, or if the surfoces hove
been domoged
mechonicolly, use the MP 1-106
dresser, or the MP 1-157
iig with
universol guicc
rings.
Reconditioning of Comshqft Beorings
lf on oversize
comshoft is to be f itted (ex-
cessive beoring cleoronces in on otherwise
sound block), drive out the plug
on the reor
side of the cvlinder block ond reom
the beor-
ings to dimensions specif ied in the following
Toble:
-0.025To
Grind
For grir
shoft by t
between 1
'Ihe
reor
ond there
for detoils
beoring.
For grir
prepored
clomped t,
pins must
Externol Col
Nomir iourn
Stondord
1st regrin
2nd regrin
3rd regrin
Stondond comshoft
Diometer of beoring in cylinder block
mm
+0.02s
38.5
+0.021
Oversize comshoft lsg
l-
38s-
l-;- -0.041
-0.020
The numerical symbols of the beorings (
l-lll)
indicote the respective
front, centre, ond reor
beari ngs.
Close the newly
mochined bore with o new
plug ond seol
it with o dob of point.
A poor
seoling would result in oil leoking
from the
engine into the clutch.
When reboring the bore for
the comshoft,
observe the centre distonces of the cronkshoft
ond comshoft. Otherwise the timing choin will
be either too slock or too tout. For the correct
distonces see
Fio. 2.6/3. Reconditioning
of Volve Toppet Guides
lf there is on excessive cleoronce in the
guides (beorings) of the volve toppets,
it is
possible to recondition the guides
ond to re-
ploce stondord toppets by toppets
of o lorger
diometer. The centre line of the beorings
is per-
pendiculor (normol) to the seoting foce
of the
cylinder block. The relotive dimensions
of the
beoning ond toppet ore
specified in
the Toble
below: o
L_r
_-L1il I toi .ll
-t
QZt0.l -T-
zi
A'ry
@)
2.7 CRANKSHAFT
AND ITS ACCESSORIES
The cronkshoft hos three rnoin beorings ond
four cronkpin beorings. lt is o forging with sof t,
not hordened iournols. When
worn, it
must be
reground to dimensions os per
Toble for fitting
oversize big-end ond moin beoring shells
os
well os cn oversize guide
ring. Cronkshoft Beoring
(for
clutch shoft)
It will be driven or pressed
into the shoft
lubricoted with the recommended greose
with
its cover turned outword.
After its pressing-in,
odd odditionol greose
by forcing it into the
shoft bore behind the beoring.
Use the extroctor MP 1-109 for
the removol
of the
beoring. Diometer of comshoft
iournols
mm
_ =l__i tl
Volve Toppet Diometer
of Beoring
in Cylinder Block, mmToppet
Diometer
mm
Stondord
on;rsizt- 21
+0.021 21
-0.020
21.2 21.2-0.007
42 4th