Chevrolet 10 Series 1970, Service Manual

Page: 328 / 671

ENGINE 6-6
N O N -V E N T E D
CAP
VALVE
VALVE
FLAME ARRESTOR
N O N -V E N T E D CAP
CLOSED POSITIVE IN LINE (TYPICAL) CLOSED POSITIVE V 8 (3 0 7 -3 5 0 ) (TYPICAL)
FW D
FLAME ARRESTOR
N O N -V E N T E D CAP
CLOSED POSITIVE V 8 (3 6 6 )
FLAME ARRESTOR
VALVE
F ig , 11—C rankcase V e n tila t io n Systems
intake m anifold d estroys engine p erform an ce a n d
econom y.
Service Fuel Lines and Fuel Filter
1. Inspect fuel lin es fo r kinks, bends o r leaks and c o r ­
re c t any d efects found. R e fe r to Section 8 fo r the
c o r r e c t fabrication and replacem ent proced u res fo r
fuel lines.
2. Inspect filt e r and rep la ce i f plugged.
NOTE:
If a com plaint o f poor high speed p e r-
F ig . 12—C rankcase V e n tila t io n F ilte r
form ance exists on the veh icle, fuel pump tests
d escrib ed in Section 6M should be p erfo rm ed .
Service Cooling System
1. Inspect cooling system fo r leaks, weak hoses, loose
hose clam ps and c o rre c t coolant le v e l, and s e rv ic e
as requ ired.
NOTE:
A cooling system p ressu re test, as d e­
scrib ed in "A d d itio n a l Checks and A d ju stm en ts"
in this section, may be p erfo rm e d to detect
internal o r external leaks within the cooling
system .
Check and Adjust Accelerator Linkage
1. Disconnect a c c e le ra to r rod at carbu retor throttle
le v e r .
2. Hold ca rb u retor throttle le v e r in wide open position.
3„ P u ll a c c e le ra to r rod to wide open position. (On
v e h ic le s equipped with automatic transm ission, pull
through detent).
4. Adjust a c c e le ra to r rod to fr e e ly enter hole in c a r ­
bu retor throttle le v e r .
NOTE:
A c c e le r a to r linkage is outlined in detail
in Section 6M.
5. Connect a c c e le ra to r rod at throttle le v e r.
Service Crankcase Ventilation (Fig. 11)
A ll engines have a "C lo s e d P o s itiv e ” ventilation s y s ­
tem u tilizin g m anifold vacuum to draw fum es and con­
taminating vapors into the combustion cham ber where
they a re burned. Since it a ffects e v e ry part o f the en­
gine, crankcase ventilation is an im portant function and
should be understood and s e rv ic e d p ro p erly .
In a " C lo s e d P o s it iv e " ventilation system , a ir is
drawn through the engine, (through a regulating v a lve)
into the m anifold, drawing crankcase vapors and fumes
with it to be burned. The "C lo s e d P o s it iv e " ventilation
C RANKCASE VEN TIL A T IO N FILTER!
CHEVROLET TRUCK SERVICE MANUAL