Chevrolet 70 1969 Series, Shop Manual

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G ASO LINE ENGINES 6A-6
GASOLINE ENGINE TUNE-UP CHART
(ENGINE MODELS 401M AN D 478M)
Specifications apply to all engines unless otherwise indicated.
T Y P E A N D N U M B E R O F C Y L IN D E R S 60°V-6
C Y L IN D E R C O M PR ESS ION (PSI) .................... 125
SPARK PLUGS
Spark Plug Make and N o ................. AC-CR42N
Spark Plug G a p ...................................... 0.035"
Spark Plug Tightening Torque (Ft.-Lbs.)
32
IGNITION D ISTR IBUTOR
Dwell Angle (Degrees) . ....................... 31-34
Point Gap (New) .................................... 0.019"
Point Gap ( U s e d ) .................................... 0.016"
Contact Lever Spring Tension (Oz.) . . 19-23
FIRING O R D E R 1-6-5-4-3-2
IGNITION TIM IN G (See N O T E below). . 10° BUDC*
V A L V E L A S H
Intake...................................................... 0.012"
Exhaust ................................................... 0.018"
EN G IN E G O V E R N O R SETTIN G S (Full Load R P M )**
401M ........................................................ 3400
478M ........................................................ 3200
E N G IN E IDLING SPEED ( R P M ) ............... 400
F U E L PUMP PRESSURE (P S I)....................... 5-6.5
C Y L IN D E R H E A D B O L T
T O R Q U E (FT.-LBS.) ............... 60-65
N O T E : At engine idle speed with vacuum advance line disconnected and plugged.
♦Recommended setting when using average nation-wide regular fuel. Timing
must be retarded as required when lower octane fuel is used.
**No load speed is approximately 300 rpm higher than full-load speed.
ENGINE REPLACEMENT
V-6 GASOLINE ENGINE
(CONV. CAB MODELS)
E N G IN E R E M O V A L
1. Drain radiator.
2. Disconnect battery.
3.. Remove hood attaching parts and remove
hood.
4. Remove grille and radiator braces.
5. Remove radiator and heater hoses.
6. Disconnect oil cooler lines from radiator
(some engines do not have oil cooler).
7. Remove grille and radiator. Also remove
front bumper.
8. Disconnect fuel supply line, s
9. On vehicles with air compressor, discon­
nect air lines.
10. Disconnect engine ground strap.
11. Disconnect exhaust pipes from exhaust
manifolds.
12. Disconnect accelerator and choke controls
from carburetor.
13. Disconnect tachometer drive (when used).
Also disconnect oil gauge pressure line (whenused).
14. If vehicle is equipped with power steering,
the power steering pump may be removed from
engine and fluid lines may remain connected dur­
ing engine removal.
15. The hydraulic clutch release cylinder line
should remain attached to cylinder, the cylinder
rod disconnected from release lever, and cylinder
mounting bolts removed to permit engine removal
without draining fluid from clutch release system.
16. Attach lifting sling to overhead hoist to take
weight off front mounting. Remove mounting bolt.
17. Remove clutch housing-to-flywheel hous­
ing bolts, then carefully work engine forward to
disengage transmission drive gear from clutch
driven member splines. When free from transmis­
sion, raise engine and remove from vehicle.
E N G IN E IN S T A L L A T IO N
Engine installation is accomplished by revers­
ing "Removal" procedure, meanwhile taking nec­
essary precautions to maintain cleanliness and to
avoid damaging components.
After engine is installed, check operation of
control linkage. Fill cooling system and check for
leaks.
Fill crankcase with engine oil of recommended
grade and viscosity.
Start engine, make adjustments at carburetor,
set ignition timing, and adjust valve lash.
N O T E : If engine has been run in on test stand,
the foregoing adjustments will have been made
previously and need not be repeated.
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M ANUAL