1 9 7 1
VOLVO
142 144

pg. 26 TECHNICAL DESCRIPTION

Engine compartment, B 20 A and B 20 B
1. Charging relay
2. Expansion tank
3. Alternator
4. Flap housing for air preheating
5. Carburettor (B 20 A)
6. Air cleaner (B 20 A)
7. Air cleaner (B 20 B)
8. Carburettors (B 20 B)
9. Oil filler cap
10. Ignition coil
11. Distributor
12. Oil dipstick
13. Starter motor
14. Windscreen washer motor and fluid container
15. Data plate
16. Brake servo
17. Fuel filter
18. Brake fluid container
19. Reversing light relay (Starter relay BW 35)
20. Relay, elec. heated rear window
21. Step relay, fullbeam-dipped headlights
22. Steering box
23. Battery
24. Radiator

pg. 27 TECHNICAL DESCRIPTION


Engine compartment, B 20 E
1. Radiator
2. Temperature sensor, induction air
3. Expansion tank
4. Charging relay
5. Air cleaner
6. Pressure sensor
7. Alternator
8. Cold start relay
9. Relay for fuel pump
10. Main relay for fuel injection
11. Throttle switch
12. Cold start valve
13. Inlet duct
14. Auxiliary air regulator
15. Temperature sensor, coolant
16. Oil filler cap
17. Injectors
18. Pressure regulator
19. Ignition coil
20. Distributor
21. Windscreen washer motor and fluid container
22. Data plate
23. Starter motor
24. Brake servo
25. Oil dipstick
26. Brake fluid container
27. Relay for reversing lights (starter relay BW 35)
28. Relay for elec. heated rear window
29. Step relay for fullbeam-dipped headlights
30. Relay for extra lighting
31. Fusebox
32. Steering box
33. Battery

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 (not B 20 E)
On certain markets the vehicle is fitted with an evaporative control system which counteracts fumes from the carburettor and fuel tank.

Air preheating (not B 20 E)
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 E)
The B 20 E engine is fitted with an electronic fuel injection system.
This system includes an electronic control unit (8) which converts the impulses from the various sensors in the engine to control signals which regulate the four solenoid-actuated fuel injectors (16). 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 (15) in the distributor, the operating temperature by the sensor (17) for the coolant, the temperature of the induced air by the sensor (1) and the engine load by the pressure sensor (7) 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 (4). 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 (13) which maintains a constant pressure of 30 psi (2 kp/cm2) in the fuel line with the help of a pressure regulator (14).
On certain markets the car is fitted with a system to check fuel evaporation from the fuel tank.

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

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 A engine, the exhaust emission control is obtained through the carburettor which is specially designed for this purpose. On the B 20 B engine, the exhaust emission control is provided partly through the carburettors and partly by means of a special induction manifold provided with throttles and a preheating chamber, see illustration above.

On the B20E, the exhaust emission control is provided by the electronic fuel injection system. When driving at low speeds, the throttles are closed so that the fuel-air mixture is forced to pass the preheating chamber. When higher output is required, the throttles open so that the fuel-air mixture flows directly to the cylinders.

Cooling system
The cooling system is of the sealed pressure type and incorporates a circulation pump. A special expansion tank prevents air from circulating with the coolant as this would cause corrosion in the cooling system.
On certain markets the fan is driven via a slip coupling which permits a max. fan speed of approx. 3,500 rpm, resulting in a lower noise level and increased output.

POWER TRANSMISSION
Clutch

The function of the clutch is to transmit power from the engine to the gearbox. 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


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

Automatic transmission
As an alternative, 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
For certain markets, the Volvo 142, 144 de Luxe and Volvo 142, 144 Grand Luxe models are fitted with an overdrive. With the overdrive, it is possible to reduce the 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 connecting link between the gearbox and the 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 rear axle. The rear axle is of the hypoid type, that is, the drive pinion lies below the center line of the drive shafts.

Differential lock
On certain markets, a differential lock can be obtained as extra equipment. A rear axle with a differential lock automatically transmits the tractive power to the wheel having the best road grip when a wheel begins to spin. Except for the differential unit, 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 unit, 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 car has independent front suspension. 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 below the rear window. This system provides good ventilation in the vehicle as well as effective demisting of the rear window and side windows. The rear window is also electrically heated.

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 cables to the headlights, parking lights and interior lighting, however, are not controlled by the ignition switch but 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. The Volvo 142, 144 Grand Luxe have also two foglights.
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 number plate. On certain markets the car is fitted with marker lights mounted on the side of the mudguards.
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 A and B
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 12 V, 60 Ah
9 = Starter motor 1 h.p.
10 = Reversing light switch on gearbox
11 =Warning lamp for headlight fullbeams, 1.2
12 =Step relay for fullbeam and dipped headlights and also headlight flasher
13 = Horn ring
14 = Alternator 12 V, 35 Ah
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 = Switch for headlight flasher and turn indicators
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 = Windscreen wipers
38 = Windscreen washer
39 = Solenoid for overdrive
40 = Interior light 10 W
41 = Switch for heater
42 = Switch for windscreen 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 15 W
51 = Brake stop lights 25 w
52 = Rear lights 5 W
53 = Licence 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 (U.S.A.)
61 = Relay for electrically heated rear window
62 = Connector unit for instrument
63 = Warning buzzer for ignition (U.S.A.)
64 = Door switch, left
65 = Terminal board
66 = Clock

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

pg. 35 TECHNICAL DESCRIPTION


pg. 36 TECHNICAL DESCRIPTION

Wiring diagram B 20 E
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 12 V, 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 Ah
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 1.2W
23 = Connector
24 = Glove locker light
25 = Warning light for overdrive, 1.2W
26 = Switch for headlight flasher and turn indicators
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 = Windscreen wipers
38 = Windscreen washer
39 = Solenoid for overdrive
40 = Interior light 10 W
41 = Switch for heater
42 = Switch for windscreen 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 15 W
51 = Brake stop lights 25 W
52 = Rear lights 5 W
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 (U.S.A.)
61 = Relay for electrically heated rear window
62 = Connector unit for instrument
63 = Warning buzzer for ignition (U.S.A.)
64 = Door switch, left
65 = Terminal board
66 = Clock
67 = Fuel pump
68 = Main relay for fuel injection
69 = Relay for fuel pump
70 = Relay for start valve
71 = Pressure sensor
72 = Throttle valve switch
73 = Cold start valve
74 = Temperature sensor I
75 = Temperature sensor II
76 = Injection valves
77 = Triggering contacts
78 = Electronic control unit
79 = Spark plugs
80 = Fuel box
81 = Foglights
82 = Relay for foglights
83 = Switch for foglights

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

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 handbrake.


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