Chevrolet 1970 Owner's Manual page 84

What you should know about Air Pollution Control
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*Positive Crankcase Ventilation (PCV)
All General Motors vehicles are equipped with P ositive
Crankcase Ventilation-a system which permits no crank-
case emission to be discharged into the ambient air. To
function properly, the sys tem depends on the
pev
Valve
(smog valve) wh ich recirculates and burns blow- by
gases inside the engine. This valve must be clean
in
order
to maintain efficient engine operation . See service recom -
mendations present ed on last page of this section.
NE W CARB UR ETO R
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LEAN MIXTURfS,
ENGI N E IDLE
INCREASED
KEY TO
c.c.s.
SYSTEM
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--oUt
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IIOl ' lJIAUS'
HEAT EXCHANGED
FROM EXHAUST
MANIFOLD TO
UNDERHOO D
A IR FLOW
*Contro/led Combustion System (CCS)
The Controlled Combustion System, used on most vehi-
~les,
is designed to reduce exhaust air pollution by
alter-
mg the combustion process. CCS includes a special air
cleaner which incorporates thermostatic control of h eated
air to the carb uretor, a special calibrated carburetor and
distributor and related components. Complete effective-
ness of the system, as well as full power and performance
depend upon p roper engine maintenance. See
servic~
reconunendations .
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