Chevrolet 70 Series 1970, Service Manual

Page: 379 / 841

GASOLINE ENGINES 6A-8
GASOLINE ENGINE TUNE-UP SPECIFICATIONS
V 6 GASOLINE ENGINE TUNE-UP CHART
(ENGINE MODELS 401M AND 478M)
S p ecifications apply to all engines u n le ss otherw ise indicated.
TYPE AND NUMBER OF CYLINDERS . . 60°V-6
CYLINDER COMPRESSION (P S I )...................... 125
SPARK PLUGS.
Spark Plug Make and N o................... A C-C R -43N
Spark Plug G a p ............................................. 0.035"
Spark P lug Tightening Torque (F t.-L b s.) . . 32
IGNITION DISTRIBUTOR
D well Angle (D e g r e e s)..................................31-34
Point Gap ( f t e w ) .............................................0.019"
Point Gap (U se d ).............................................0.016"
Contact L ever Spring T ension (Oz.) . . . 19-23
FIRING O R D E R ..................................... 1 - 6 - 5 - 4 - 3 - 2
IGNITION TIMING (See NOTE b e lo w ). 10° BUDC*
VALVE LASH
I n t a k e ............................................................... 0.012"
E x h a u s t ............................................................0.018"
ENGINE GOVERNOR SETTINGS (Full Load Rpm)**
4 0 1 M .......................................................................
3 4 0 0
4 7 8 M ....................................................................... 3200
ENGINE IDLING SPEED (R PM )................... 500-550
FUEL PUMP PRESSURE ( P S I ) ...................... 5-6.5
CYLINDER HEAD BOLT
TORQUE ( F T . - L B S . ) ..................................60-65
NOTE: At engine idle speed with vacuum advance lin e disconnected and plugged.
♦Recom m ended settin g when using average nation-w ide regular fuel.
Tim ing m ust be retarded a s required when low er octane fuel is used.
**No load speed i s approxim ately 300 rpm higher than full load speed.
ENGINE REPLACEMENT
V6 ENGINE REPLACEMENT FOR
CONVENTIONAL CAB MODELS
ENGINE REMOVAL
1. Drain radiator.
2. D isconnect battery.
3. R em ove hood attaching p arts and rem ove
hood.
4. Rem ove g r ille and radiator b r a c e s.
5. R em ove radiator and heater h o ses.
6. D iscon n ect o il c o o ler lin es from radiator
(som e engines do not have o il cooler).
7. R em ove g r ille and radiator. A lso rem ove
front bum per.
8. D isconnect fuel supply lin e.
9. On v e h ic le s w ith air co m p re sso r, d iscon ­
nect air lin e s.
10. D iscon n ect engine ground strap.
11. D iscon n ect exhaust p ip es from exhaust
m anifolds.
12. D iscon n ect a c c e le r a to r and choke con­
tr o ls fro m carburetor.
13. D iscon n ect tachom eter drive (when used).
14. If v eh icle i s equipped with pow er s t e e r ­
ing, the pow er ste er in g pump may be rem oved
from engine and fluid lin e s may rem ain connected
during engine rem oval.
15. D isconnect clutch r e le a s e linkage.
NOTE: The hydraulic clutch r e le a s e cylinder
lin e (when used) should rem ain attached to cylinder,
the cylinder rod disconnected from r e le a s e le v e r ,
and cylinder mounting b olts rem oved to perm it
engine rem oval without draining fluid from clutch
r e le a s e sy ste m .
16. Attach slin g to overhead h oist to take
w eight off front mounting. R em ove mounting bolt.
17. R em ove clutch h ou sin g-to-flyw h eel hous­
ing b olts, then carefully work engine forward to
disengage tra n sm issio n drive gear from clutch
driven m em ber sp lin e s. When fr e e from tra n s­
m issio n , r a is e engine and rem ove from v eh icle .
ENGINE INSTALLATION
Engine installation is accom plished by r e ­
v ersin g "Engine Rem oval" p rocedure, m eanwhile
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL