Volvo 164 1971, Instruction Book

Page: 27 / 65

TECHNICAL DESCRIPTION
Exhaust emission control
The engine is fitted with an exhaust emis-
sion control system which produces a
more exact and leaner mixture ratio be-
tween fuel and air resulting in a more
complete combustion and thereby cleaner
exhaust gases.
The system consists of specially adapted
carburettors and an intake manifold pro-
vided with a preheating chamber and con-
trol throttles.
When driving at low speed, the throttles
are closed so that the fuel-air mixture
passes the preheating chamber.
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Cooling system
The cooling system is of the sealed pres-
sure type and incorporates a circulation
pump. When the engine is cold the coolant
circulates only inside the engine. As the
engine warms up, a thermostat valve starts
opening the outlet to the radiator.
A special expansion tank prevents air from
circulating with the coolant as this would
cause corrosion in the cooling system. The
fan is driven by a slip-coupling which
keeps the fan speed at about max. 2500
r.p.m.
POWER TRANSMISSION
Clutch
The function of the clutch is to transmit the
power from the engine to the gearbox. The
clutch is of the single dry plate type. Pres-
sure on the pressure plate is obtained
from a diaphragm spring which in turn is
controlled mechanically by the clutch
pedal via the throw-out yoke. (Hydraulic
operation for vehicles with right-hand
drive.