1 9 7 2
VOLVO
142 144

pg. 26 TECHNICAL DESCRIPTION

Engine compartment, B 20 B
1. Foam plastic filter, evaporative control system
2. Charging relay
3. Expansion tank
4. Alternator
5. Flap housing for air preheating
6. Radiator
7. Oil filler cap
8. Air cleaner (B 20 B)
9. Carburetors (B 20 B)
10. Oil dipstick, automatic transmission
11. Oil dipstick, engine
12. Ignition coil
13. Distributor
14. Starter motor
15. Windshield washer motor and fluid container
16. Data plate
17. Brake servo
18. Brake fluid container
19. Steering box
20. Reversing light relay (Starter relay BW35)
21. Relay, elec. heated rear window
22. Step relay, fullbeam-dipped headlights
23 Fuel filter
24 Battery

pg. 27 TECHNICAL DESCRIPTION


Engine compartment, B 20 F
1. Radiator
2. Charging relay
3. Expansion tank
4. Air cleaner
5. Pressure sensor
6. Alternator
7. Throttle switch
8. Relay for fuel pump
9. Main relay for fuel injection
10. Foam plastic filter, evaporative control system
11. Cold start valve
12. Inlet duct
13.Auxiliary air regulator
14. Temperature sensor, coolant
15. Pressure regulator
16. Injector
17. Ignition coil
18. Oil filler cap
19. Distributor
20. Windshield fluid container
21. Data plate
22. Dipstick
23. Starter motor
24. Brake servo
25. Brake fluid container
26. Reversing light relay (starter relay BW 35)
27. Relay, elec. heated rear window
28. Step relay, fullbeam-dipped headlights
29. Fusebox
30. Battery
31. Steering box

pg. 28 TECHNICAL DESCRIPTION


ENGINE
The engine is a four-cylinder, water-cooled unit with overhead valves.
The cylinder block is made of special alloy cast iron and is cast in a single unit. The cylinder liners, which are surrounded by cooling jackets, are machined directly in the block. The cylinder head has separate inlet and exhaust ports, one for each valve.

Lubricating system
Engine lubrication is taken care of by a gear pump located under the crankshaft in the sump. The pump is driven by a gear from the camshaft.
From the pump the oil is forced through the oil filter and then along oilways to the various lubricating points. A relief valve is built into the oil filter and prevents the oil pressure from reaching excessively high values. The oil filter is of the full-flow type, that is, all the oil passes through the filter before continuing on to the engine lubricating points.

Fuel system, B 20 B engine
The engine is fitted with twin carburetors of horizontal type. The diaphragm-type fuel pump draws fuel from the tank and pumps it to the carburetors.

Air preheating, B 20 B engine
The engine is equipped with thermostatically controlled air preheating. This ensures that the temperature of the induced air is maintained constant, thus counteracting ice formation and reducing the warming-up period after cold starting.

pg. 29 TECHNICAL DESCRIPTION

Fuel system, B 20 F
The B 20 F engine is fitted with an electronic fuel injection system.
This system includes an electronic control unit (7) which converts the impulses from the various sensors in the engine to control signals which regulate the four solenoid-actuated fuel injectors (15). The control signals influence the opening times of the injectors and thereby the amount of fuel injected.
The mixture of fuel and air is modified the whole time according to the conditions under which the engine is running. Engine speed is governed by the triggering contacts (13) in the distributor, the operating temperature by the sensor (18) for the coolant, the temperature of the induced air by the sensor (1) and the engine load by the pressure sensor (6) which is connected to the inlet duct. In addition, the control unit is provided with information concerning the position of the throttle valve by means of the throttle valve switch (3). This information is "computerized" in the control unit and re-transmitted in the form of control impulses to the injectors.
Fuel is injected into the inlet ports in the cylinder head just before the intake valves. The fuel is delivered to the injectors via an electric fuel pump (11) which maintains a constant pressure of 30 psi (2 kp/cm2) in the fuel line with the help of a pressure regulator (14).
The car is fitted with a system to check fuel evaporation from the fuel tank.

Principle of operation, fuel injection system B 20 F
1. Temperature sensor for induction air
2. Air cleaner
3. Throttle valve switch
4. Cold start valve
5. Inlet duct
6. Pressure sensor
7. Control unit (electronic)
8. Battery
9. Fuel tank
10. Fuel filter
11. Fuel pump
12. Fuel filter, discharge side
13. Triggering contacts in distributor
14. Pressure regulator
15. Injectors
16. Thermal timer contact
17. Idling adjusting screw
18. Temperature sensor for coolant
19. Auxiliary air regulator

pg. 30 TECHNICAL DESCRIPTION


Exhaust emission control
Your Volvo is fitted with exhaust emission control, that is, a system which as a result of better mixing and distributing of fuel and air provides a more complete combustion and thereby cleaner exhaust gases.
On the B 20 B engine, the exhaust emission control is obtained through the carburetor which is specially designed for this purpose. On the B 20 F, the exhaust emission control is provided by the electronic fuel injection system.

Cooling system
The cooling system is of the sealed pressure type and incorporates a circulation pump. A expansion tank prevents air from circulating with the coolant as this would cause corrosion in the cooling system. The fan is driven via a slip coupling which permits a max. fan speed of approx. 2,500 rpm, resulting in a lower noise level.

POWER TRANSMISSION
Clutch

The function of the clutch is to transmit power from the engine to the transmission. The clutch is of the single dry plate type. Pressure on the pressure plate is obtained from a diaphragm spring which in its turn is controlled by the clutch pedal via the throw-out yoke.

pg. 31 TECHNICAL DESCRIPTION


Transmission
The transmission has synchromesh on all forward gears. Since it is fitted with helical gears and the gear lever is rubber-insulated, excellent sound insulation is obtained.

Automatic transmission
As an alternative, your Volvo can be fitted with a BW 35 automatic transmission. In principle it consists of two main components - a hydraulic torque converter and a hydraulically operated epicyclic gearbox with a control system. The converter serves as a clutch and as an extra gear between engine and gearbox.

Overdrive
As an alternative the Volvo 142, 144 E can be fitted with an overdrive. With the overdrive, it is possible to reduce engine speed while maintaining road speed. This is less wearing on the engine and reduces fuel consumption at the same time.

pg. 32 TECHNICAL DESCRIPTION


Propeller shaft
The propeller shaft, which is the link up between transmission and rear axle, is divided into two sections. The forward section is flexibly mounted at its rear end in a rubberized ring.

Final drive
Engine torque is transmitted via the propeller shaft to the rear wheels through the final drive. The final drive is of the hypoid type, that is, the drive pinion lies below the center line of the drive shafts.

Limited slip
A limited slip differential can be obtained as extra equipment. A rear axle with a limited slip automatically transmits the tractive power to the wheel having the best road grip when a wheel begins to spin. Except for the differential, the rear axle is similar in design to a conventional rear axle.
Do not rotate a jacked-up rear wheel if the other rear wheel is still on the ground. Due to the differential, there is still drive on the wheel in contact with the ground. Rotating the jacked-up rear wheel would thus move the other rear wheel and may cause the car to topple off the jack.

Rear axle
The rear axle is carried on two support arms the front ends of which are bolted to the body. The rear axle casing is secured to the support arms by means of levers. Two torque rods are journalled on the casing and the body. A torque rod prevents lateral movement of the body and rear axle in relation to each other.

pg. 33 TECHNICAL DESCRIPTION


FRONT END AND STEERING
Front end

The front suspension units are mounted on a strong box member. The member is bolted firmly to the front section of the body. The front wheels are journalled in tapered roller bearings. The front springs consist of coil springs in which telescopic shock absorbers are fitted. The car is provided with stabilizers secured to the lower control arms and to the body.

Steering
The steering is of the cam-and-roller type. Movements of the steering wheel are transmitted via the worm on the steering column to the roller on the pitman shaft, which in turn operates the wheels through a linkage system.

HEATING SYSTEM
The heating system is a combined warm and fresh air system. The incoming fresh air is blown by a fan through the cell system of the element into the vehicle. By means of the various ventilation controls, the fresh air can be warmed up and directed to suitable places in the car.
From there the air passes out of the car through a number of extractor vents under the rear window. This system provides good ventilation in the vehicle as well as effective demisting of the rear window and side windows.

pg. 34 TECHNICAL DESCRIPTION

ELECTRICAL SYSTEM
The electrical system is of the 12-volt type and is fitted with a voltage-regulated alternator. The starter motor is operated by means of the ignition switch. This switch is also the main switch for the rest of the electrical system. The headlights, parking lights and interior lighting, however, are not wired via the ignition switch so they can be switched on and off without the ignition key being in position.

Lighting
The front lighting on the vehicle consists of two headlights (full and dipped beam) together with two turn indicators and a parking light.
At the rear, the lighting consists of two tail lights, turn indicators, brake warning lights and reversing lights. There are also two lights for the rear license plate. The car is also fitted with marker lights mounted on the side of the fenders. The interior lighting consists of a roof light and one in the glove compartment.
Concerning replacement of bulbs, see pages 52, 53, 54 and 55.

Wiring diagram B 20 B
1 = Turn Indicators 32 cp
2 = Parking lights 5 W
3 = Dipped headlights 40 W
4 = Fullbeam headlights 45 W
5 = Horn
8 = Distributor
7 = Ignition coil firing order 1-3-4-2
8 = Battery 12V, 60 Ah
9 = Starter motor 1 h.p.
10 = Reversing light switch on gearbox
11 = Warning lamp for headlight fullbeams, 1.2 W
12 = Step relay for fullbeam and dipped headlights and also headlight flasher
13 = Horn ring
14 = Alternator 12 V, 35 A
15 = Relay for reversing lights
16 = Fusebox
17 = Charging regulator
18 = Brake stop light contact
19 = Flasher relay and switch for warning flashers
20 = Warning light for parking brake, 1.2 W
21 = Warning light for oil pressure, 1.2 W
22 = Warning light for battery charging 1.2 W
23 = Connector
24 = Glove locker light
25 = Warning light for overdrive, 1.2W
26 = Warning buzzer, ignition key
27 = Fuel gauge
28 = Voltage regulator
29 = Temperature gauge
30 = Oil pressure sender
31 = Switch for overdrive, on transmission
32 = Warning light for flashers, 1.2W
33 = Instrument panel lighting, 2X3 W
34 = Temperature gauge
35 = Lighting for heater controls
36 = Heater
37 = Windshield wipers
38 = Windshield washer
39 = Solenoid for overdrive
40 = Interior light 10 W
41 = Switch for heater
42 = Switch for windshield wipers and washer
43 = Rheostat for instrument panel lighting
44 = Lighting switch
45 = Ignition switch
46 = Cigarette lighter
47 = Door switch, right
48 = Switch for parking brake control
49 = Fuel level indicator unit
50 = Reversing lights 32 Cp
51 = Brake stop lights 32/4 Cp
52 = Rear lights 32/4 Cp
53 = License plate lighting 2x5 W
54 = Switch for overdrive
55 = Brake warning contact
56 = Switch for start block and reversing lights BW35
57 = Switch for glove locker light
58 = Electrically heated rear window
59 = Switch for electrically heated rear window
60 = Side marker lights
61 = Main relay, ignition switch key
62 = Connector unit for instrument
63 = Switch for indicator blinkers and fullbeams
64 = Switch for emergency warning flashers
65 = Warning lamp, choke
67 = Clock
69 = Connector
70 = Shift positions light, autom. transmission

Color code:
SB = Black R = Red
BR = Brown GN = Green
GR = Grey W-R = White-red
BL = Blue BL-Y = Blue-yellow
W = White GN-R= Green-red
Y = Yellow

pg. 35 TECHNICAL DESCRIPTION


pg. 36 TECHNICAL DESCRIPTION

Wiring diagram B 20 F
1 = Turn indicators 32 cp
2 = Parking lights 5 W
3 = Dipped headlights 40 W
4 = Fullbeam headlights 45 W
5 = Horn
6 = Distributor
7 = Ignition coil firing order 1-3-4-2
8 = Battery 12V, 60 Ah
9 = Starter motor 1 h.p.
10 = Reversing light switch on gearbox
11 = Warning lamp for headlight fullbeam, 1.2 W
12 = Step relay for fullbeam and dipped headlights and also headlight flasher
13 = Horn ring
14 = Alternator 12 V, 55 A
15 = Relay for reversing lights
16 = Fusebox
17 = Charging regulator
18 = Brake stop light contact
19 = Flasher relay and switch for warning flashers
20 = Warning light for parking, brake, 1.2W
21 = Warning light for battery charging, 1.2 W
23 = Connector
24 = Glove locker light
25 = Warning light for overdrive. 1.2 W
26 = Warning buzzer, ignition key
27 = Fuel gauge
28 = Voltage regulator
29 = Temperature gauge
30 = Oil pressure sender
31 = Switch for overdrive, on transmission
32 = Warning light for flashers, 1.2 W
33 = Instrument panel lighting, 2X3 W
34 = Temperature gauge
35 = Lighting for heater controls
36 = Heater
37 = Windshield wipers
38 = Windshield washer
39 = Solenoid for overdrive
40 = Interior light 10 W
41 = Switch for heater
42 = Switch for windshield wipers and washer
43 = Switch for instrument panel lighting
44 = Lighting switch
45 = Ignition switch
46 = Cigarette lighter
47 = Door switch, right
48 = Switch for parking brake control
49 = Fuel level indicator unit
50 = Reversing lights 32 Cp
51 = Brake stop lights 32/4 cp
52= Rear lights 32/4 cp
53 = License plate lighting 2X5 W
54 = Switch for overdrive
55 = Brake warning contact
56 = Switch for start block and reversing lights BW35
57 = Switch for glove locker light
58 = Electrically heated rear window
59 = Switch for electrically heated rear window
60 = Side marker lights
61 = Relay for electrically heated rear window
62 = Connector unit for instrument
63 = Switch for indicators and fullbeam flashers
64 = Switch for emergency warning lights
65 = Warning lamp, choke
66 = Contact, choke control
67 = Clock
69 = Terminal board
70 = Thermal timer
71 = Fuel pump
72 = Main relay for fuel injection
73 = Relay for fuel pump
74 = Pressure sensor
75 = Throttle switch
76 = Cold start valve
77 = Temperature sensor I
78 = Temperature sensor II
79 = Injection valves
80 = Triggering contacts
81 = Electronic control unit
82 = Spark plugs
83 = Fusebox
84 = Foglights
85 = Relay for foglights
86 = Switch for foglights
87 = Shift positions light (autom. transmission)

Color code:

SB = Black
BR = Brown
GR = Grey
BL = Blue
W = White
Y = Yellow
R = Red
GN = Green
W-R = White-Red
BL-Y = Blue-Yellow
GN-R = Green-Red

pg. 37 TECHNICAL DESCRIPTION


pg. 38 TECHNICAL DESCRIPTION


BRAKES
The brake system is of the two-circuit type with disc brakes all round. The system is provided with a tandem-type master cylinder and a directly-operating booster cylinder. When the brake pedal is depressed, the master cylinder is operated mechanically via the booster cylinder, this increasing the pedal force about three times. The brake pressure is transmitted hydraulically from the master cylinder through the brake to the wheel cylinders. The pistons in these are then pressed outwards and apply the brake pads. The pressure lines to the rear wheel brakes are provided with a reducer valve which prevents locking of the rear wheels. The principle of the two-circuit system is that both the front wheels are connected to one rear wheel, that is, should there be a failure in one of the circuits, there is always braking power on both front wheels and the other rear wheel. So at normal pedal pressure the braking effect of one of the circuits is 50 %, but when pedal pressure is increased, about 80 % of the full braking power can be obtained in the one circuit. This provides maximum safety and prevents lateral dragging and rear-end lurching. With the engine stopped, the booster assists the braking a further two or three times after which the pedal pressure must be increased about three times as much in order to obtain a braking power corresponding to the braking power available with the engine running. The parking brake operates the rear wheels mechanically as the brake discs have also been designed as brake drums in order to incorporate the shoes for the parking brake.


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