1980 SKODA 105S engine oil

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

{
Smoll End ond
Big End Alignment
A misolignment of the centre line
of the
smoll-end bush ond big-end beoring
or the bore
for the big-end
beoring shells must never ex-
ceed 0.03
mm per 'lO0
mm of the connecting
rod length. For checking
ond olignment use
the
MP 1-102 or 1-159 f ixture.
Insert the odiusting pin
into the fixture ond
set both its diol indicotors to
zero. Clomp the
connecting rod without shells
into the fixture,
threod the pilot
pin
in it, ond swing
down the
connecting rod. The recdings
of the diol indi-
cotors will
show ony misolignment of the
smoll
ond big end. The moximum misolignment must
not exceed 0.03
mm os olreody mentioned.
Check for misolignment in two plones by tilting
the diol indicotors.
Two pilot
pins ore supplied, one with o
di-
ometer of 20 rnnr. the
other with o diometer of
20.05 mm, to motch the gudgeon
Pins.
To Motch Connecting Rod
with Gudgeon Pin
ond Cronkshoft
With regord to the reciprocoting movement
of the piston,
the gudgeon pin must hove
the
smollest possible
cleoronce in the
connecting
rod small end (ony lorger cleorcnce results
in
pin knocking). Therefore
select from
severol
gudgeon pins
one which will
be o close running
fit in the smoll-end
bush. lf no suclr pin is
ovoiloble, reom
tlre bush but never exceed the
moximum toleronce limits.
An oversize buslr lros to be
reomed to o nom-
inol diometer of 20.05 mm. For
the respective
dimensions refer to
the Toble supplied with
gudgeon pins. The big"end
beorings
i:;hells)
inouta be
selected occording to the nominol
diometer of the cronkpin. The
shells lrove no
diometer ntorking
oncl hove to be identif !ed
by meosuring their woll thickness with o mi'
crometer.
Motching Big-end Beoring
shells
with Cronkpins
MotchingCronkpin o"|,,n"iifl",,l ro,u,on
nominol diometer
1 thick"ness
mm
mm mm
45 (stondord)
44.75 (1st
regrinding)
44.50 (2nd
regrinding)
44.25 (3rd regrinding)
44 {:lttr regrinding) 1.490
1.615
1.740
1.865
1 990 0.007
Numericol lderrtif icotion of
Connecting Rods
For better identificotion, {igures con
be
stomped on the bosses of
the connecting rod
big end ( see Fig 2 11
1) . The f igures corre-spond with
the
number of the respective
gVtin-
derwithwhich theconnecting rod
is ossembled.
When replocing o connecting rod,
provide the
new connecting rod
with its very some identi-
ficction numbel. Stomp
the figures os much
toword the for end of the boss os possible to
ovoid fouling the loterol guide foce.
2.12 CYLINDERS, CONNECTING RODS
AND PISTONS
o) Only o cylinder (liner)
ond piston of
equot
'
diometer ond the some toleronce closs con
be ossembled qs
s unit.
b) Theengine cs qn
ossembly unit con befitted
cnly with cylinder liners ond pistons
of the
some diometer, the pistons being
of the
some weight grnLtp.
The inclividuol cylinder'cnd-piston qssemblies
con be, however, of dif
ferent toleronce
closses. On the othe'r hond, connecting rods
of only the sqme weight group
con be used-
These ore the cc;tditions for
the correct op-
erotion of pistons in the
cylinders ond for the
correct boloncing of the cronk mechonism.
For detoils concerning dimensions (diometers),
toleronce closses (cylinder liners, pistons) ond
weight groups
(connecting rods ond pistons)'
refei to fhe chcpters deoling with
the
individuol
pc|rts"
To Assembie Cylinder Liner
with Piston
qnd Connectirrg Rod
1. Toke cylinder liners ond pistons with
motching dinrensions, i. e.
cylinder liners of the
some boie (they need
not be necessorily of the
scrme toleronce closs), pistons
of the some
cliometer <,nrl tcieronce closs
to motch those of
the cvlinclr:i iitrers
ond of the sonre weight, oncl
connectitrct rorls, of rtne of
tlle twtl weiglrt
cl roLr PS.
lti''
DK 1161 2.
1
OCCorl Selec'
cyl i nd
tolpro
the (
motch Son
pin or
gudge
in wh
suitob
bush.
Mor
respor
with v
meric<
Rod'.
3.L
the gr-
80"c i Sme
home
some
threod
Pin, o
circlip
on thr
pressi I
Fit
hole ir
the orr
4.F
or exp
detoils
the ri
groove
5- Pr
the crc
ond co
2.13 I
In or
ter ist ic
coms o
comsh<
c leoror
the cor
Volve '
with
lntoker
open be
close o
Fi,c 2.1211 -
Press'f ittirrg
of Gudgeon Pin into
Piston Usinq MP 1-i04
Drift
50

Alternoting
cylinder No. 1
cylinder No.3
cylinder No.4
cylinder No. 2 Adjust cleoronce
on
cylinder No.4
cylinder No.2
cylinder No. 1
cylinder No.3
Fi1.2.1312
-
Volve Cleoronce Adjustment link from the choin
front side ond fit the clip
from the reor with its open end pointing in
the
direction opposite to the choin movement.
Before storting work on the volve geor,
re-
move the oil sump (engine
bottom cover to
which the timing geor
cover is bolted, the suc-
tion stroiner being ottoched to the cronkshoft
centre beoring cover) ond lock
the cronkshoft
in position
in the oxiol direction by depressing
the clutch pedol,
if removol of the entire engine
is not intended for onother purpose.
For speciol
points of the removol refer to
Chopter 2.4.
2.14 WATER PUMP
Disossembly 1. Unlock the wosher of the belt pulley
nut,
remove the nut ond pull
off the belt pulley
using
the MP 1-120 puller (o
fixturre for
Skodo MB 1000
cors) or o universol puller,
for the bolts of which
it is necessory to
cut threods M 8 in the belt
pulley holes.
By pulling
off the belt pulley,
occess will be
goined to the nuts fostening the pump
to the
engine. The some procedure
holds good
when
dismontling the pump
ofter it hos been removed
from the engine.
2. Withdrow the keyfrom
the shoft ond, using
the drift MP 1-121, drive
or press
out the shoft.
Then lift owoy the
housing plote
from the
seoting foce of the pump.
3. Remove the circlip locking the outer boll
beoring in position.
Proceeding from the reor
side of the pump
housing, drive out the boll
beorings with their spocer tube, ond remove
the
rubber seoling rring
from the housing.
Reossembly 1. Smeor the rubber seoling ring with greose
ond insert it into the pump
housing.
Use the
MP 1-123 drift to drive home the inner boll
beoring (without
sheet guord) pocked
with
greose. When opplying the drift,
fit its guide
ring into the bore for the
oute,r boll beoring.
2. Fit the gosket
on the pump
seoting foce
ond ploce
the pump plote
with its cemented-on
gosket (focing outwords from the pump)
over it.
Fosten the plote
to the pump provisionolly
with
one bolt to prevent
the gosket
from being dom-
oged during the following ossembly
iobs.
Insert the rubber seol,
wosher, ond conicol
spring into the speciol (bokelite)
seoling ring
of the pocking glond.
Instoll the spring
with
its nose
into the hole in
the bokelite pocking.
Slip the ossembled pocking glond
on the shoft
with the spring toword the shoft geor,
ond drive
the shoft home into the pump
beoring, while
supporting the beoring with the MP 1-123 drift. Fig.2
4. Fit t
shoft ond
stolling th
in positior
it with gre
sheet guor
5. Top
t
lieve the r
@@@@
DK 1240
Fig.2.1313 -
Volve Arrongement in Cylinderr Heod
Block disks -
exhoust volves
White disks -
intoke volves
Timing Choin ond Timing
Geors
Modified chain and gears
fitted since October
1979 recognised by
squared gearteeth
and chain
with split rollers.
The timing choin hos no slock odiuster (ten-
sioner). A slock choin does not substontiolly
offect the volve geor
occurocy but its operotion
is noisy. Therefore
its correct length should
be
ensured either
o) by selecting o suitoble choin from o number
of choins ovoiloble -
try it on the timing
geors, o1r
b) by replocing the stondord comshoft geor
with on oversize geor
(with greoter
toler-
onces). The comshoft geors
ore groded
in
keeping with their progressive
size (tol-
eronces) into closses A, B ond C. With the
exception of
closs A, the closs morking
letters ore stomped next
to the punch
mork.
For trying, the choin con be disconnected
to ovoid removing ond refitting of the timing
geors. To recouple the choin, insert the coupling Fig.2.1t
52

6.
Complete the pump
ossembly by fitting
the
Stouffer lubricotor filled with
the recommended
greose.
2.15 ROCKER SHAFT AND ROCKERS
Assembly (on
Skodo 105 engine)
1. Instoll the lock ring, ploin
wosher, ond
spring wosher on the ro6ker shoft
with both
ends plugged.
Smeor the shoft with oil, fit the
rocker (with
its orm with the thrust foce de-
flected toword the next ossembled ports),
the
shim, the rocker support, ond the other
orm
def lected toword the support, i. e. the complete
rocker unit of cylinder
No. 1.
2. Then slip the spring,
the rocker, the sup-
port, the shim,
ond the next rocker, i.e.
the
complete rocker unit of cylinder
No.2, on the
shoft.
3. Threod on the spring ond, using the mirror
orrongement of the ossembled
rocker units,
instoll the rocker
units of the remoining
two
cylinders. Use o lock ring supplemented
with
o ploin
ond o spring wosher
to lock the os-
sembled ports
in position.
The rocker support of the cylinder No.4 must
be provided
with on oil hole
to provide
for the
supply of oil to the rocker shoft.
4. Compress
the springs
by holding down the
rocker orms ond lubricote
oll loterol contoct
surfoces with oil.
Assembly (on Skodo 120 L
ond 120 LS engines)
The rocker shoft is provided
with two od-
ditionol rocker supports fitted from
the outside
of the rocker units (the
shoft is longer), re-
plocing woshers obutting
on the lock rings.
For
the rest, the ossembly is identiccl
with the pro-
cedure described in porogrophs
1 to 4 obove.
NJote: Rocker orms
on the Skodo 120 LS en-
gine ore shorter (18.5
mm) thon those on the
Skodo -120
L ond Skodo 105 engines,
in order
to obtoin o higher rotio.
Disossembly
Remove the lock ring from the shoft
end ond
strike off the
entire volve nocker geor
from
the
shoft.
2.16 CYLINDER HEAD, VALVES
AND
SPRINGS
The cylinder heod is o costing of speciol grey
cost iron. The volve seots ond guides
ore cost
ond mochined directlv in tlre heod. The volves ore of different
diometers, the intoke volves
being lorger. Outer (exhoust)
ports
ore single,
oll remoinlng ore doubled, i.e. bifurcoted
ond
bronching to two volves in odioining
cylinders.
The centre exhoust port
bronches to the cyl.
inders No.2 ond 3, the neighbouring
intoke port
to the cylinders No. 1 ond 2, ond No. 3 ond 4.
The cylinder heod con be hondled
in the cor os
o unit. Of the individuol
iobs, only
the reploce-
ment of volve springs,
cotters, ond cylinder
heod bolts con be corried out with the engine
in. position in the cor. For oll the remoining
iobs, the
cylinder heod hos to be removed
from
the cor.
To remove
the volve springs,
screw out
the
sporking plugs ond, using o tommy
bor with
o curved end (steel
bor of obout 5 mm dio-
meter), broce
the volve to prevent
it from
sliding down into the combustion
chomber.
To Remove
Cylinder Heod from Engine
1. Let
the engine cool down before removing
the cylinder heod to preclude
worping of its
beoring surfoce.
2. Droin
the coolont into o cleon vessel (see
Chopter 15.13), detoch oll ports
connecting the
cylinder heod to the vehicle,
ond remove
oll
ports which ore likely
to obstruct the removol.
3. Remove the oir cleoner,
lift owoy
the
cylinder heod cover, ond remove
the nuts ond
bolts holding down
the cylinder heod (on
en-
gines of Skodo 120 L
ond 120 LS cors, two
bolts olso hold down
the end rocker
shoft sup-
ports) reversing the order of the numbers
in-
dicoted in Fig. 2.1611.
By pulling
the exhoust
monifold, disengoge the
cylinder heod ond lift
it owoy.
To Refit Cylinder
Heod on Engine
. 1.
Locote the cylinder heod gosket
on o per-
fectly cleon surfoce of the cylinder
block (cleon
Fi1.2.1611- Tightening Diogrom of Cylinder
Heod Bolts ond Nuts
For tightening torques see Chopter
1.8 the
cylinc
the oilwo,
structed c
Releose
once odjur
heod. lf nr
the rocker
2. Swin<
down the
porogroph
opply the
liminory o
the sequ€
(Fig. 2.16/
shoft suppr
3. Adjus
ter 2.13,
re
cleoner, rer
tighten oll
Cylinder Hr
Disossem
heod on o r
o support i
it does
not
o iob from
t
An exomple
1. Remove
the cosing
control, end
geor ofter
supports.
Fig.2Je
For holding
c
bolt M 8 scrt
rocker-shoft st
1 -
MP 1-113
v,
2 -
MP 1-114
v
Itl
I
I
/\.
-
( 3 r--{ 4)
\-/
\II
l
/
,/
t___v'
?,3
"'@-:lO
54

The rocker-shqft
support hos o poper
seol
preventing leokoge of the oil fed from the cyl-
inder block to the rockers vio the support. lf
o reody-mode seol (gosket
) is not ovoiloble,
moke it yourself
using poper
0.1 mm thick.
A thicker seol
is unpermissible os it
would
couse c distortion of the rocker shoft. The hole
in the seol
must coincide with the oil hole
of
the rocker.
Apply the seol
ond ref it the
exhoust ond in-
toke monifolds. For detoils see
Chopter 2.3.
porogroph 30.
6. Reinstoll the thernrostotic temoeroture
control cosing with its gosket
ond do not forget
to put
spring woshers under the nuts.
Note: When reossembling
the cylinder heqd
of on engine removed
from the cor, it is odvis-
oble to proceed
with the
iobs os
per
porogroph
5 ond 6 with the cylinder heod refitted
on the
engine to focilitote
the tosk.
lf the cylinder heod gosket
hos been reploced
with o new one, invite the customer to bring in
the cor ofter
trqvelling 500
to 1,000 kilometres
for o retightening of the cylinder heod ond
odiusting of the volve cleoronce. 3. To ensure o leokproof
cond ition of the
volves, grind
them in
with their seots
in the
cylinder heod.
Volve GuideS The volve guides
ore formed directly by the
cylinder heod motericl. lf reconditioning
is
necessqry, rebore the guide
hole ond press-fit
o bush.
Volve guide bushes ore not ovoiloble os
sporre ports. They
con be mode
individuolly oc-
cording to the following drowing. The
required
moteriol is grey
cost iron of 200
N/mmz (2O
kpl
mm2) tensile strength, in
Czechoslovokio cost
iron to specificotions of theCzechoslovokSton-
dord CSN 422421.
Hoving press-fitted
the bush, correct ony
shrinkoge of the inside diometer ond, to motch
the new guides, rrecondition
the volve seots
ond grind-in
the volves.
DK 1+J6 Fig.2.16l
To Recon
These
volves fo
groph 3),
new volvt
Use o
conicol sr
with its r
1. Che
necessory
volves. F
shonk of,
eter, ond
will result
ing in ocr
seot widtl
Check 1
occordinq
Coot the"s
volve in tl
troces of
centre of t
2. Coot 1
volve with
of oil with
volve into
seot ond
1
severof tin
onother po
round the I
volve ond
grinding-in
the volve
c
grey. Use
down the v
Fi1.2.1613
-
Reconditioning Cylinder Heod
for Fitting Volve Guide Bush
Seoling of
Cylinder Heod
As o seporote unit or forming
o unit with
the cylinder block,
the cylinder heod
must be
seoled ogoinst leokoge
of goses
ond woter, i.e.
it must be gos-
ond wotertight.
1. When replocing
some of the bolts pro-
truding into the woter
iocket, seol
them
with
point. The woter
iocket of the
cylinder
heod
must be leckproof
when tested with woter
under c pressure
of 0.5 Mpo (5
kg/cm2).
2. lf it is necessory
to restore the flotness
of t-he cylinder heod
moting surfoce,
,egiind
the
surfcce only to the leost possible
exte-nt so os
not to increose
the engine
compression rotio.Valve
guide
tolerances
Guide 7.94 -
HB +
O.O22
o.oo mm
lnlet Valve 7.94 -
F7
t 9 9?q .n-
+ 0.013
0.025
56 Fi1.2.1614
-
Volve Guide Bush x
1Tr9

2,15-2.'t8
3. The
leokoge test should
be corried out with
the cylinder heod fully ossembled by pouring
o smoll quontity
of petrol
into the exhoust ond
intoke ports.
The petrol must not leok post
the
moting foce of the volve
in the combustion
chomber. Another method involves pouring
o smoll omount of thin oil into the combustion
chomber ond introducing compressed oir into
the exhoust ond intoke ports
using, for
exomple,
o rubber
cone. No oir bubbles must oppeor
oround the volve heods.
This test con be simplif ied by omitting the
fitting of vclve springs while pressing
the
volves into their seots by hond using o suitoble
Jixture (fork)
for holding down the volves.
Volves The volves
ore forgings of speciol high-tem-
peroture steel with o conicol seoling surfoce
ond ho,rdened stem end. The
volve heods ore
of unequol diometers (lorger
with intoke volves
ond smoller with exhoust volves).
Current reconditioning
of the conicol seoling
surfoce is done by grinding-in
with the respect-
ive seot. lf o mojor repoir is required,
regrind
the seoling surfoce
of the volve heod
on
o grinding
mochine to on ongle of 91 o
+10',
ond then grind
it in with the seot.
When regrinding the conicol surfoce, it is
obsolutely essentiol to keep it in
correct olign-
ment with the volve stem.
Valve Springs
rcs/po1201S
Outer Inner
Free Length 45.85
43.645.20
Wire 3.75 2.5
Diameter 4.OO
Mean Spring 26.75
18.5 26.5
urameter
T
Spring Pres-
sure
I nstal led
length L""En-I
3Omm Length
Length
30mm 29mm
299-358 N108-127N
460N hondle)
ond the short oil pumP,
to the cost oil
sump the 330 mn-r long dipstick ond
the longer
oil pump -
see Chopter 2.18.
2.18 TIMING GEAR COVER .
OIL PUMP
ln oddition to timing geors,
the timing geor
cover houses olso the oil pump
(f
orm ing its
housing) ond the distributor drive.
A generol
description of removing the timing
geor cover from the engine con be found in
Chopter 2.4
ond for detoils, regording its f
itting
on the engine, refer to
Chopter 2.3,
porogrophs
22 to 25.
The engine with the sheet oil sump hos the
shorter oil pump
with the suction stroiner
holder 72 mm long. The
engine with the
cost oil
sump hos the pump
30 mm longer.
Assembling Oil
Pump
Coot the pump geors
ond the drive geo'r
shoft
with oil, ond instoll them into the timing geor
cover. Insert the gosket
ond close the pump
with the lid with suction pipe
ond stroiner. Use
spring woshers to prevent
the lid screws from
s lcrcken ing.
Fi1.2.1811- Timing
Geor Cover Assembly -
Sectionol View
(for better illustrotion, the pinned
connection
of the shoft ond geor
is somewhot turned, its
correct position
being described in the text)
2.17
OIL SUMP
A sheet oil sump is used on engines with
o 68 mm cylinder bore.
Use o rubber gosket
when instolling the oil sump
on the engine.
Engines with o cylinder bore of 72 mm hove
o cost ond ribbed
oil sump. For its instollotion
use its respective
cork gosket.
A sheet boffle
is bolted
over the bottom of the oil sump.
Use
bolts with spring woshers to bolt it
down.
Relotion between oil sump,
oil dipstick, ond
oil pump:
To the sheet
oil sump oppertoins the dispstick
of o totol length
of 305 mm (including
its For
egi
stroiner v brrocket r
65 mm), 1
(the leng
proximott
The go
provides
geors. lf
gosket is
thicker tl" To prer
obnormol
respectivr
limits spr
Seol F it
the
t ig hte
n in1
thot it pr
edge of tl
Assemblir 1. Thre
brocket, s
pointing r
odio.4c in the pr
bore (pin
the pinne
When c
sure thot
line with
is importr
ignition d
To prev
ing durin
o pilot
m<
Then con
using o sr
2. After
ensure tl'
0.1 mm) I
3. Fit t
into the f
under the
Betwee
driven
I driven
I Axiol
c
I betwee
I and lid
58

d)
e) f) choke
plunger
sticking in its
bottom
position storting worm engine
too high fuel level in floot chomber
incorrectly odiusted
idle run unstick
the plunger
or reploce it with
o new one
odjust the
floot
odiust idle
run correctlY
2.2O FUEL PUMP
Technicol DescriPtion
The model JIKOV MF 3407 fuel pump
is of
the diophrogm ond
lever type, controlled by the
round disc of the comshoft. The suction
motion
of the diophrogm is octuoted by the
lever, the
dischorge motion by the spring of
the dio-
phrogm. Fuel flows through o stroiner, o mud
trop, ond the suction volve to the delivery
volve. A priming lever is provided
for hond
priming of the fuel. The moving mechonism
is
lubricoted with oil
sploshed from the cylinder
block. Stroke of the driving disk 4
mm
Suction heod 1.5
mm
Deliveryheod. 2mm
Pump dischorge ot 2,000 strokes
per minute ond free outflowwithout
counter-pressure 30
ltrs/hr.
Mointenonce, Repoirs, Disossembly
ond Reossembly
For routine
mointenonce (cleoning
of the
mud-trop screen) see Chopter 15.3. After hoving
operoted the hond-priming lever lift it
till it
engoges sofely in its locked position.
ln the cose of o defect, inspect the diophrogm
ond check the volves for leokoge. After hoving
removed the pump
from the engine, remove the
mud trop, seporote the upper port
from the
lower port,
ond remove two screws, holding
down the thrust plote,
to lift owoy the volves.
Swill oll ports
in petrol
ond blow off with com'
pressed oir. Reploce domoged ports
with new
ones. lf necessory, remove the diophrogm from the
octuoting lever in
the lower port
of the fuel
pump (its
monufocturer recommends the dio-
phrogm to be reploced ofter obout 50,000 kilo-
rnetres with o new
one). Do not stretch the
spring of the diophrogm ond do not olter its
compression force chorocteristic in ony woy.
Do not forget to put
fibre pocking rings
underthe
volves
when reossembling the
fuel
PumP.
Put o spocer ring under the suction volve (close
to the mud trop). Fig.2.2Ol1 shows
the pos-
itions of volves ond the holding-down thrust
plote. Put the spring
of the diophrogm into
the
lower port
oi the pump
ond engoge the pin
ot
the diophrogm with the octuoting lever. Oper-
ote the hond lever
to compress the dioPhrogm
oncl hold it in position by inserting o
rod of 4.5
to 5 mm diorneter (for
exomple the
shonk of
o drill, etc.) between the octuoting lever
ond
the woll of the pump
lower
Port.
Now bolt both pump
ports
together so thot
the mud trop is on the
right-hond side when
viewing the pump from obove
ond the fostening
flonge from the front. Use spring
woshers
under the clomping bolts.
Fig.2.2011 -
Section Through
Fuel Pump
lf it is necessory to verify
the dischorge of
the pump
by o test, note the following require'
mentswhich the pump
must meet otl80strokes
per minute:
o) 15 ltrs/hr. ot f ree outf low without
fuel
counterpressure
b) minimum pressure
of 0.018 MPo (1.8
m of
woter column) ot
o zero off'toke of fuel
c) o dry pump
must drow fuel from o
depth of
1.5 m in 16 seconds.
Fuel Pump Defects ond Their Removol
1. Foulty fuel
supply
o) clogged mud trop
b) domoged diophrogm
2. Fuel pump
does not hold fuel
o) dirty or defective volves cleon it
reploce it
with o new one
wosh them in petrol,
reploce defective
volves with new ones
66