Page 121
Idling
The carburetor has no special idling system. When the engine is idling, the negative pressurization in the vacuum
chamber of the carburetor is low, with the result that the
gap between the vacuum piston and bridge is small. Most
of the jet is therefore blocked by the thick end of the
fuel needle and only a small quantity of fuel, corresponding to the idling demand, is drawn into the engine. For
engine idling speeds, the fuel-to-air ratio is controlled by
the jet and the fuel needle and applies to the whole of
the engine speed range. The idling is adjusted by means
of the throttle spindle stop adjusting screw. In the case
of twin-carburetor engines, the idling speed is set by adjustment of the adjusting screw on the front carburetor
only. An adjusting screw is located between the throttle
spindles of the two carburetors for synchronization of the
two throttles valves.
In order to maintain a constant fuel/air mixture regardless of engine temperature, the carburetor is equipped
with a temperature compensator. The temperature compensator consists of an air valve controlled by a bi-metal
strip. The valve opens when the carburetor temperature
reaches approx. +50°F (+10°c). The additional air is introduced via a passage which opens in front of the piston.
9
5
10
11
12
6
7
13
1-------14
Normal driving
CARBURETOR
WITH THROTTLE
1. Damper cap
2. Diaphragm
3. Compensating hole
4. Oil damper
5. Float chamber ventilation
6. Float valve
7. Float
8. Spring
9. Fuel holes
OPEN
When the throttle is opened, a vacuum is generated in the
vacuum chamber which is equal to that in the inlet manifold due to equalization via the holes in the piston. As atmospheric pressure prevails on the underside of the diaphragm, the piston is pulled up and the airflow through
the carburetor is increased. At the same time the fuel
flow also increases as the tapered needle, which is attached
to the piston, is withdrawn from the jet.
10. Adjusting screw
11. Vacuum piston
12. Starting fuel hole
13. Throttle
14. Vacuum hole
15. Fuel needle
16. Jet
17. Float chamber
Acceleration
In order to produce a temporarily richer fuel mixture on
rapid opening of the throttle (acceleration), a damping
device is provided in the spindle of the vacuum piston.
This consists of a small piston called the oil damper
mounted on a rod. The damper runs in oil. When the
throttle is opened quickly, the negative pressurization in
the vacuum chamber is abruptly increased. When the vacuum piston is raised, the oil damper is pressed against its
seating and prevents oil from flowing past from below
the damper to above it; this brakes the movement of the
vacuum piston, temporarily generating a harder vacuum
above the jet and momentarily enriching the fuel-air mixture.
The downward movement of the vacuum piston is assisted
by a spring. The oil level in the hollow spindle of the vacuum piston, sho1Jld be so high that the oil damper dips inoil before the thread of the screw cap.engages the vacuum chamber cover. (For twin-carburetors, the oil level
should be at least 1.38 in (35 mm) above the bottom of
the damper.) NOTE! Do not fill the space above the
spindle. Use oil for automatic transmission according
to Fords specification M2C.33F or M2C.33G.
to
S 5595
VACUUM PISTON WITH ADJUSTABLE
FUEL NEEDLE
SAM!
200-7
Page 122
Overrun braking
FUEL SYSTEM, INJECTION ENGINES
As from model 1977, the carburetor is equipped with a
deceleration valve which ensures satisfactory combustion
during engine overrun. As from model 1978, the carburetor is equipped with an electrically controlled deceleration devi,ce (see Section 2~ ,Jr.iqu
The engine is fitted with a Bosch, Cl (continuous injection) injection system.
An electric fuel pump provides fuel at a constant pressure
to the mixture control unit. The latter consists of an air
fl01,v,sen59,rwhic;:!l,measures the flow of air to the engine
and which ac;ts mechanically on the fuel distributor. The
fuel distributor provides the injection valves with the correct amount of fuel. The fuel is injected continuously in.to the inlet manifold immediately upstream of the inlet
valve. Refer to section 240 for a detailed description.
1
2------f-1\IL-..II;)
3
4
5
AIR CLEANER
6
The air cleaner is mounted at the front of the left-hand
wheel housing. In addition to cleaning the incoming air,•
it also absorbs the suction noise. The air cleaner element
which consists of a special paper cartridge must not be
washed or moistened. The only servicing measures permitted are to blow the cart.ridge clean by means of compressed air or to replace it.
On cars with carbureted engines, the air cleaner is connected to the carburetor by means of a hose.
On cars with injection engines, the mixture control unit
is bolted directly onto the air cleaner.
7
8
S4410
DECELERATION VALVE, UP TO AND INCL MODEL 1977,
NORMAL DRIVING
1
2------r-tl"=~l
3--4
5
6
7
11
8
S4-411
DECELERATION VALVE, UP TO AND INCL. MODEL 1977,
ENGINE OVERRUN
1.. Adjusting screw
2. Rubber ring
3. Cover
4. Nut
5. Spring
6. Channel to top of
diaphragm
200-8
7. Diaphragm
8. Valve
9. Throttle
10. Inlet channel for
fuel-air mixture
11. Outlet channel for
fuel-air mixture
SAAB
Page 123
AIR PREHEATER
Thermostatically controlled air preheating, as from
model 1978
Manuallyadjustable, up to and incl. model 1977
A thermostatically controlled valve which governs the
air preheating according to the ambient air temperature
is located in the intake of the air cleaner.
The valve housing has two air intakes, one for cold air
and one for heated air which is drawn in through a hose
running from a cover on the exhaust manifold.
The valve is actuated by a thermostat in the cold-air intake which senses the temperature of the ambient air.
At temperatures under 43°F (S°C) (Saab 99 Turbo 23°F
(-5°C)) only heated air is inducted into the engine.
At temperatures above 65°F ( 1S°C) (Saab 99 Turbo 41 °F
(5°C)) only cold air is inducted into the engine.
At temperatures between 43°F (S°C) and 64°F (1S°C)
(Saab 99 Turbo 23°F and 41°F (-5°C and +5°C)) the
valve admits varying proportions of heated and cold air.
Cars with carburetor engines (and injection engines as
from model 1977) are equipped with a preheater valve
with two settings.
In the "Summer" setting, the air is drawn in direct from
outside, while in the "Winter" setting, air is drawn in
THERMOSTATICALLY
CONTROLLED AIR PREHEATING,
AS FROM MODEL 1978
AIR PREHEATER, INJECTION ENGINE, MODEL 1977
through a hose from the covers surrounding the exhaust
manifold.
When the outside temperature is regularly below 10°c,
the valve should be in the winter setting.
For checking and adjusting the CO-setting, the valve
should be in the summer position.
EXHAUST SYSTEM
The exhaust system comprises three parts. A muffler is
mounted in the front pipe. The middle section consists of
a pipe and a muffler mounted crosswise in front of the
rear axle. The rear pipe runs above the rear axle and
emerges on the left-hand side of the car below the rear
bumper.
Earlier 1975 model cars are fitted with the same exhaust
system as that of the model 197 4.
SA'B
.L
200-9
Page 124
COOLING SYSTEM
The cooling system is of pressurized type with a crossflow radiator and expansion tank.. The water pump is located in the engine block and is powered by a bevel gear
from the idler shaft. The thermostat is located in a housing bolted to the front end of the cylinder head. The radijitor fan is electrically driven and controlled by a thermostat. When the pump is working and the thermostat is
dosed, coolant circulates through the cylinder block, cylinder head, inlet manifold and then through a by-pass passage back to the water pump. When the heater valve is
open, coolant will also circulate through the heat exchanger. When the thermostat is open, coolant will also circulate from the thermostat housing, through the radiator,
expansion tank and back to the water pump.
As from model 1977, the engine is equipped with a 3-way
thermostat. When the engine is running at a very high
temperature (i.e. when the thermostat is practically wide
open), the by-pass passage to the water pump will be
closed. This fo~ces all coolant to circulate through the
radiator.
WATER CIRCULATION
4. Thermostat
5. Temperature transmitter
a Impeller
200-10
2
3
3-WAY THERMOSTAT,
AS FROM MODEL 1977
1. To radiator
2. From engine block
3. To water pump
IN THE COOLING SYSTEM
1. Radiator
2. Radiator fan
3. Expansion tank with pressure cap
6. Coolant pump
7. Fan motor
1 --
9. Heater oore
10. Thennostat a>ntrolled valve
11. Thermostat switch, radiator fan
12 Radiator drain CX>Clc
13. Engine drain CX>Clc
14. Bleeder- nipple (as from model 19761
15. Cold air valve (as from model 19771
Page 125
CRAN~CASE VENTILATION
Model 1975
The crankcase ventilation is completely enclosed. The
ventilation system consists of a hose ruooing from the
valve cover 1Da T ➔1ipple on the inlet manifold. From
the T➔1ipple, the hose goes 1Dthe air cleaner (to the
throttle valve housing in cars with injection engines).
Thse is a calibrated restriction in the branch of the Tnipple connected to the inlet manifold which is designed
to ensan efficient evacuation of the gasesin the aankcase into the engine under- all ruMing conditions. The
gases are evawated via the T ➔1ipple into the inlet manifold under all conditions except when the engine is at
full load, in which case the gasesenter the engine through
the air cleaner (throttle valve housing). In cars with carbureted engines, a flame guard is fitted at the connection
of the ventilation hose to the air cleaner.
Valve-
T -nipple with restriction
S5186
DIAGRAM OF CRANKCASE VENTILATION, MODEL 1975
--.i
200-11
Page 126
As from model 1976
The crankcase ventilation is completely enclosed. The
ventilation system consists of a 3-way nipple on the valve
cover from which a small-bore hose runs to the inlet manifold and a large-bore hose to the intake system in front
of the carburetor (throttle disc). The large-bore hose is
connected as follows:
Carbureted engines: To the top of the air cleaner.
Injection engines: To the throttle housing. (One exception - on the 1977 model the hose is connected between the air cleaner and the mixture control unit.
Injection engines, as from model 1977: To the connecting
piece between the air flow meter and the air cleaner. An
angle-nipple is located inside the connecting piece and
from this a hose runs to the lower section of the air cleaner.
The sizes of the various hoses and connections are designed to ensure efficient evacuation of the gases in the
crankcase into the engine under all running conditions.
The gases are evacuated through the smaller hose directly
into the inlet manifold under all running conditions with
the exception of when the engine is at full load, in which
case the gases are evacuated through the larger hose to
the air cleaner and thence to the engine.
Carbureted engines are equipped with a flame guard at
the ventilation hose connection to the air cleaner.
5 3
1
4
2
CRANKCASE VENTILATION,
AS FROM 1976 MODEL
CARBURETED ENGINES
1. Hose 3-way nipple-inlet manifold
2. Hose to air cleaner
3. 3-way nipple
4. Inlet manifold
5. Valve cover
6. Crankcase
3
1
2
4
CRANKCASE VENTILATION, FUEL INJECTION ENGINES
1976 MODEL AND AS FROM 1978 MODEL
1. Hose, 3-way nipple - inlet manifold
2. Hose to throttle housing
3. 3-way nipple
4. Inlet manifold
5. Valve cover
6. Crankcase
CRANKCASE VENTILATION
200-12
1977 MODEL
Page 127
EXHAUST EMISSION CONTROL
A number of measures have been taken to meet the exhaust emission requirements applicable on certain markets while at the same time maintaining the good running
properties. Some of these measures are:
The engine is designed in the light of existing regulations
governing exhaust emission. Special consideration has ·
been given to the regulations in the design of the combustion chamber, the camshaft, and the compression ratio, etc.
Both injection engines and carburetor engines are equipped
with a deceleration valve to reduce the unburnt gases during engine overrun.
Cars with automatic transmission are equipped with EGR
(exhaust gas recirculation). A small portion of the exhaust gases are returned to the inlet side of the engine as
a result of which the combustion temperature is reduced,
in turn reducing the amount of nitric oxide emitted in
the exhaust.
A temperature compensator on the carburetor ensures
that the fuel-to-air ratio stays constant, regardless of
temperature. The compensator consists of a valve, governed by a bi-metallic strip, which opens to admit additional air when the temperature increases.
In some version a delay valve is attached to the vacuum
hose between the carburetor and the vacuum regulator
on the distributor, delays the formation of a vacuum in
the vacuum regulator. This means that during acceleration, the ignition advance is delayed and this helps to reduce the emission of nitric oxides.
As from model 1977, the fuel-to-air mixture adjusting
screw should either be sealed or modified so that adjustment can only be made by means of a special tool, in accordance with the European ECE regulations (tamperproof adjustment). On cars with carburetor engines, this
requirement is met by means of a top-adjusted fuel needle
which can only be adjusted by means of a special tool.
On cars with injection engines, the adjusting hole in the
air flow meter is equipped with a brass sleeve and sealed
by means of a plastic plug. Before any adjustments can
be made, the plastic plug must be removed whereupon
it will be destroyed. After adjustment, a new plug must
be installed. Service workshops are supplied with red plastic plugs while the factory uses blue plugs.
r
SAAB
200-13
Page 129
REMOVAL AND INSTALLATION
REMOVING THE POWER PLANT
For major work on the engine and transmission, the entire power plant should be lifted out... Removal of the engine by itself is not recommended.
1.
Remove the hood as follows:
Back off both the hood fastening screws. Lift off
the hood. For this you need a helper to hold one
side of the hood and help to lift it clear.
ENGINE BLOCK DRAIN COCK (SUPERSEDED BY A DRAIN
PLUG ON LATER CARS OF MODEL 19771
REMOVING THE HOOD FASTENING SCREWS
RADIATOR DRAIN COCK, UP TO ANO INCL MODEL 1976
LIFTING OFF THE HOOD
2.
3.
Detach the battery cables. Unclamp and lift out
the battery.
Drain off coolant through the radiator and engine
block drain cocks.
RADIATOR DRAIN COCK, AS FROM MODEL 1977
4.
5'l"8
Carbureted engine:
Detach the vacuum hose of the servo cylinder from
201-1
Page 130
4.
5.
5.
the inlet manifold and pull the fuel hose off the suction side of the fuel pump.
Injection engines:
a. Detach the vacuum hose of the servo cylinder
from the inlet manifold and remove the rubber
bellows between the air flow sensor and inlet
manifold.
b. Thoroughly clean the areas around the fuel line
connections on the fuel distributor and detach
the lines. Plug the holes and blank off the fuel
line ends in a suitable manner.
c. Disconnect the electrical connection on the air
flow sensor.
d. Undo the clamps on the air cleaner and remove
the air cleaner and mixture control unit.
Carbureted engine:
Undo the cable connections to the ignition coil,
temperature transmitter, oil pressure transmitter,
radiator fan, thermostat contact, headlights, headlight wipers and the switch on the gear box on cars
with automatic transmission.
Injection engine:
a. Undo the cable connections to the ignition coil,
temperature transmitter, oil pressure transmitter,
radiator fan, thermostat contact, headlights,
headlight wiper motor and the switch on the
gear box on cars with automatic transmission.
b. Disconnect the cables of the injection system at
the warm-up regulator, auxiliary air valve, cold
start valve and thermo-time switch.
6.
7.
8.
9.
c. Detach the choke control wire and sheath from
the carburetor.
Injection engine:
Detach the throttle control wire from driver and
bracket on the throttle valve housing.
Detach the hoses at the connections to the thermostat housing, radiator, inlet manifold and water
pump.
a. Remove the grille.
b. Remov·e the hood lock operating cable from its
fastenings at the dash panel and wheel housing.
c. Remove the two front sheet retaining screws and
nuts, and the four screws holding the headlights
to the body.
d. Remove the front sheet, lifting forward and upward.
Manual transmission:
Model 1975: Remove the slave cylinder and hang
it up in a convenient place. As from model 1976:
CAUTION
Do not detach the connections by pulling the cables.
Grip the connecting pieces.
REMOVING THE 'FRONT SHEET
6.
Carbureted engine:
a. Remove the air cleaner, the inlet hose and the
preheater complete with hose.
b. Detach the throttle control wire from driver and
bracket.
9.
10.
11.
12.
13.
CAUTION
Both steel and plastic versions of the gear selector
rod joint are available. The taper pin must not be
tapped out in the case of plastic gear selector rod
joints.
AIR CLEANER WITH HOSES, CARBURETED ENGINE
1. Air cleaner
2. Valve housing
3. Inlet hose
4. Preheater hose
201-2
Disconnect the clutch hose from the slave cylinder.
Plug the hose and the hole in the slave cylinder.
Automatic transmission:
Remove the protective cover from the exhaust manifold.
Disconnect the hose pipe from the exhaust manifold.
a. Disconriect the ground cable from the transmission.
b. Remove the alternator.
Jack up the front end of the car and place blocks
under the body.
Manual transmission:
a. Put the gear lever in neutral.
b. By means of tool 7840838, tap out the front
taper pin from the gear shift rod joint and pull
the rubber bellows free of the groove in the gear
select.or rod. The rubber bellows is discontinued
during model 1977 ahd need not be installed in.
older cars in connection with repair. Separate the
gear selector rod joint from the gear selector rod.
SAMI