SECTION 6M
ENGINE FUEL
CONTENTS OF THIS SECTION
Page
Carburetors 6M-1 Fuel Pumps .
Air Cleaners 6M-7 Special Tools
Page
6M-10
6M-12
CARBURETORS
INDEX
Page
General Description 6M-1
Service Procedures 6M-1
Preliminary Checks 6M-1
Idle Speed and Mixture Adjustment ........... 6M-1
Fast Idle Adjustment .................. 6M-3
Choke Adjustment 6M-3
Float Adjustment 6M-4
Page
Additional Adjustments 6M-4
Removal 6M-4
Test Before Installation 6M-5
Installation 6M-5
Fuel Filter Maintenance 6M-5
Choke Coil Replacement 6M-5
Throttle Linkage Adjustment . . 6M-6
GENERAL DESCRIPTION
Various carburetors (fig. lc) are used with Chevrolet,
Chevelle, Chevy II, Camaro and Corvette passenger
vehicles. These carburetors are designed to meet the
particular requirements of engines, transmissions and
vehicles, therefore carburetors that look alike are not
always interchangeable. (Refer to carburetor part num-
ber and/or specifications.)
Because many service procedures for the various
carburetors are similar, typical illustrations and pro-
cedures are used except where specific illustrations or
procedures are necessary to clarify the operation.
This section covers removal, installation and adjust-
ments (on engine) of carburetors. Also covered in this
section are maintenance procedures for choke coils,
throttle linkage and fuel filters. For carburetor .over-
haul procedures and additional adjustments (bench), re-
fer to Section 6M of the Overhaul Manual under the
carburetor being serviced.
Specifications for carburetors are located in the back
of this manual.
SERVICE PROCEDURES
Preliminary Checks
1.
Thoroughly warm-up engine. If the engine is cold,
allow to run for at least 15 minutes.
2.
Inspect torque of carburetor to intake manifold bolts
and intake manifold to cylinder head bolts to exclude
the possibility of air leaks.
3.
Inspect manifold heat control valve (if used) for free-
dom of action and correct spring tension.
Idle Speed and Mixture Adjustment (Except Air Injection
Reactor System)
NOTE:
This adjustment should be performed
with engine at operating temperature and park-
ing brake applied.
1.
Remove Air Cleaner.
2.
Connect tachometer and vacuum gauge to engine, then
set hand brake and shift transmission into neutral.
3.
As a preliminary adjustment, turn idle mixture
screws lightly to seat and back out 1-1/2 turns.
CAUTION: Do not turn idle mixture screw
tightly against seat or damage may result.
4.
With engine running (choke wide open) adjust idle
speed screw to specified idle speed, (automatic
transmission in drive, synchronized transmission in
neutral).
5. Adjust idle mixture screw to obtain highest steady
vacuum at specified idle speed.
NOTE:
On air conditioned vehicles, turn air
conditioning to the "on" position and hold the
hot idle compensator valve closed while adjust-
ing idle speed and idle mixture screws.
NOTE:
On Rochester BV carburetors the idle
mixture screw should be turned out 1/4 turn
from the "lean roll" position. The definition
of "lean roll" point is a 20 to 30 rpm drop
in engine speed obtained by leaning the idle
mixture.
6. Repeat Steps 4 and5 as needed for final adjustment.
NOTE:
If necessary, final adjustment of the \
carburetor may be made with the air cleaner
installed.
7. Turn engine off, remove gauges and install air
clearer.
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE FUEL 6M-5
3.
Disconnect choke rod or choke cable.
4.
Disconnect accelerator linkage.
5.
If equipped with Automatic transmission, discon-
nect TV linkage.
6. Remove carburetor attaching nuts and/or bolts and
remove carburetor.
Test Before Installation -
It is good shop practice to fill the carburetor bowl
before installing the carburetor. This reduces the strain
on the starting motor and battery and reduces the pos-
sibility of backfiring while attempting to start the engine.
A fuel pump clamped to the bench, a small supply of fuel
and the necessary fittings enable the carburetor to be
filled1 and the operation of the float and'intake needle and
seat to be checked. Operate the throttle several times
and check the discharge from the pump jets before in-
stalling the carburetor.
Installation
1.
Be certain throttle body and intake manifold sealing
surfaces are clean.
2.
Install new carburetor to manifold flange gasket (if
required).
3.
Install carburetor over manifold studs.
4.
Start vacuum and fuel lines at carburetor.
5.
Install attaching nuts and/or bolts and tighten
securely.
6. Tighten fuel and vacuum lines.
7.
Connect and adjust accelerator and TV linkage.
8. Connect choke tube or choke rod.
9. Adjust idle speed and mixture, then install air
cleaner. #
Fuel Filter Maintenance
1.
Disconnect fuel line connection at inlet fuel filter
nut.
2.
Remove inlet fuel filter nut from carburetor with a
1"
box wrench or socket.
3.
Remove filter element and spring (fig. 4c).
Fig. 5C-Choke Coil-L6 Engine
4.
Fig. 4C-Fuel Filter
Check element for restriction by blowing on cone
end, element should allow air to pass freely.
5.
Clean element by washing in solvent and blowing out.
Blow in opposite direction of fuel flow.
NOTE: Element should be replaced if plugged
or if flooding ocpurs. A plugged filter will
result in a loss of engine power or rough (pul-
sating) engine feel, especially at high engine
speeds.
6. Install element spring, then install element in car-
buretor so small section of cone faces out.
7.
Install new gasket on inlet fitting nut then install
nut in carburetor and tighten securely.
8. Install fuel line and tighten connector.
Choke Coil Replacement
L6 Engines (Fig. 5c)
1.
Remove air cleaner then disconnect choke rod upper
clip.
2.
Remove bolts attaching choke coil to manifold, then
remove choke coil and choke rod as an assembly.
3.
Disconnect choke rod from choke coil.
4.
Connect choke rod to new choke coil and install as-
sembly on manifold.
5.
Install bolts and tighten securely.
6. Adjust and connect choke rod as outlined.
7.
Start and warm-up the engine then check operation
of choke and install air cleaner.
V8 Engines (Fig. 6c)
1.
Remove air cleaner then disconnect choke rod upper
clip.
2.
Remove choke coil as follows:
WITH ROCHESTER 2GV CARBURETOR
• Remove the choke coil shield by prying with a
screw driver in the cut out provided then re-
move the choke rod.
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE FUEL 6M-7
5. On vehicles equipped with automatic transmission
hold throttle rod in full throttle position, pull TV
rod to full detent position and adjust TV rod to just
enter hole on throttle lever, then connect TV rod at
throttle lever.
NOTE:
If equipped with anti-stall device (dash-
pot),
set carburetor fast idle cam on high step
and adjust dash-pot to just contact throttle
lever.
327
CU.
IN.
427
CU.
IN.
Fig.
8C—Throttle Linkage-Corvette
AIR
CLEANERS
INDEX
Page
General Description 6M-7
Service Procedures . . 6M-8
Polyurethane. Element 6M-8
Maintenance 6M-8
Oil Bath 6M-8
Page
Maintenance
...........* 6M-8
Oil
Wetted
Paper
Element
6M-9
Replacement
* . 6M-9
Testing 6M-9
Tool J-7852 . 6M-9
GENERAL DESCRIPTION
Air cleaners on all models operate primarily to re-
move dust and dirt from the air that is taken into the
carburetor and engine. All air cleaners on engines
equipped with "Closed Positive" ventilation incorporate
flame arresters. Every 12,000 miles the flame ar-
resters should be removed, cleaned in solvent and blown
dry with compressed air.
An oil wetted polyurethane element air cleaner (fig. 1A)
is standard equipment on In Line engines. This type
cleaner element is reusable and should be removed,
cleaned, re-oiled and reinstalled every 12,000 miles or
more often during dusty or other adverse driving con-
ditions. The optional, oil bath air cleaner (available on
Chevrolets with L6 engine) should be cleaned and re-
filled with oil at oil change intervals.
On the V8 engines,, a replaceable, oil wetted paper
element type is used (fig; 2A). Both ends of me paper
element are bonded with plastisol sealing material.
The improved oil wetted paper elements have increased
filtering capacity over their dry paper predecessors.
Oil on the paper causes the element to become diBcolored
by a small amount of dirt but does not necessarily mean
the element is plugged or reduced in efficiency. Every
12,000 miles or more often during dusty or other adverse
driving conditions, either replace oil wetted paper ele-
ment or test element using ToolJ-7825.
CHEVROLET CHASSIS SOVICE/MANUAL
ENGINE FUEL 6M-8
^T^l^^/'-vN
COVER
BOTTOM
Fig. 1A—Polyurethane Element Air Cleaner
OIL RESISTANCE
SEAL
BOTTOM
BONDED PAPER
ELEMENT
COVER
Fig. 2A—Paper Element Air Cleaner
SERVICE
PROCEDURES
POLYURETHANE ELEMENT
Maintenance
1.
Remove cover wing nut, cover and filter element.
2.
Visibly check the element for tears or rips and re-
place if necessary.
3.
Clean all accumulated dirt and grime from air
cleaner bottom and cover. Discard air horn to air
cleaner gasket.
4.
/Remove support screen from element and wash
element in kerosene or mineral spirits; then squeeze
out excess solvent (fig. 3A).
NOTE: Never use a hot degreaser or any sol-
vent containing acetone or similar solvent*
5.
Dip element into light engine oil and squeeze out
excess oil.
NOTE: Never shake, swing or wring the ele-
me.nt to remove excess oil or solvent as this
may tear the polyurethane material. Instead,
"squeeze" the excess from the element.
6. Install element'on screen support (fig. 4A).
7.
Using a new gasket, replace air cleaner body over
carburetor air horn.
8. Replace the element in the air cleaner. Care must
be taken that the lower lip of the element is properly
placed in the assembly and that the filter material
is not folded or creased in any manner that would
cause an imperfect seal. Take the same precautions
when replacing the cover that the upper lip of the
element is in proper position.
9.<•
Replace cover and wing nut.
OIL BATH
Maintenance
L Remove air cleaner assembly.
2.
Remove cover and filter element assembly.
Empty oil out of
accumulated dirt.
cleaner and clean out all oil and
Fig. 3A—Cleaning Polyurethane Element
Fig.
4A—Polyurethane Support
CHEVROLET CHASSIS SERVICE MANUAL
SECTION 6T
AIR INJECTION REACTOR SYSTEM
INDEX
Page
General Description 6T-1
Maintenance Procedures 6T>1
Drive Belt. ...-..' 6T-1
Inspection 6T-1
, Adjustment . . 6T-1
Replacement 6T-1
Drive Pulley . . . . 6T-1
Replacement 6T-1
Pump Pulley ....................... 6T-1
Replacement. 6T-1
Air Manifold, Hose and Tube
...........>*.
6T-2
Inspection . . 6T-2
Replacement 6T-2
Check Valve (s) 6T-3
Page
Inspection 6T-3
Replacement . . 6T-3
Mixture Control Valve 6T-3
Inspection 6T-3
Replacement 6T-3
Air Injection Tube 6T-4
Inspection . . . ... . . . .... 6T-4
Replacement 6T-4
Air Injection Pump 6T-4
Inspection 6T-4
Replacement . 6T-4
Pressure Relief Valve Replacement 6T-4
Special Tools 6T-5
GENERAL
The Air Injection Reactor (A.I.R.) System (fig. 1) con-
sists of: the air injection pump (with necessary brackets
and drive attachments), air injection tubes (one for each
cylinder), a mixture control valve, check valves (one for
In Line engines, two for V8 engines) and air manifold as-
semblies, tubes and hoses necessary to connect the
various components.
Carburetors and distributors for engines with the
A.I.R. System are designed, particularly, for these en-
gines;
therefore, they should not be interchanged with or
replaced by a carburetor or distributor designed for an
engine without the A.I.R. System.
The air injection pump (fig. 2) picks up fresh filtered
air from the air cleaner, compresses the air and injects
it through the air manifolds, hoses and injection tubes
into the exhaust system in the area of the exhaust valves.
The fresh air ignites and burns the unburned portion of
the exhaust gases in the exhaust system, thus minimizing
exhaust contamination.
The mixture control valve (fig. 3) when triggered by a
sharp increase in manifold vacuum, supplies the intake
manifold with fresh filtered air to lean out the fuel-air
DESCRIPTION
mixture and prevent exhaust system backfire.
The check valve(s) prevent exhaust gases from entering
and damaging the air injection pump, as back flow can
occur even under normal operating conditions.
When properly installed and maintained, the A.I.R.
System will keep exhaust emissions well below require-
ments. However, if any A.I.R. component or any engine
component that operates in conjunction with the A.I.R.
system should malfunction, the exhaust emissions might
be increased.
Because of the relationship between "Engine Tune
Up"
and "Unburned Exhaust Gases", the condition of
Engine Tune Up should be checked whenever the A.I.R.
System seems to be malfunctioning. Particular care
should be taken in checking items that affect fuel - air
ratio such as the crankcase ventilation system, the
carburetor and the carburetor air cleaner.
Because of the similarity of many parts, typical illus-
trations and procedures are used except where specific
illustrations or procedures are necessary to clarify the
operation. For Repair Procedures on the Air Injection
Pump,
refer to the Passenger Chassis Overhaul Manual.
MAINTENANCE PROCEDURES
Drive Belt
Inspection
• Inspect drive belt for wear, cracks or deterioration
and replace if required.
• Inspect belt tension and adjust if below 50 lb. using a
strand tension gauge.
Adjustment
• Loosen pump mounting bolt and pump adjustment
bracket bolt.
• Move pump until belt is tight (55±5 lb. used belt or
75±5 lb. new belt using a strand tension gauge) then
tighten adjustment bracket bolt and mounting bolt.
CAUTION: Do not pry on the pump housing.
Distortion of the housing will result in extensive
damage to the Air Injection Pump.
Replacement
• Loosen pump mounting bolt and pump adjustment
bracket bolt then swing pump until drive belt may be
removed.
• Install a new drive belt and adjust as outlined above.
Drive Pulley .
Replacement
• Remove drive belt as outlined above then replace
drive pulley.
• Install and adjust drive belt as outlined above.
Pump Pulley
Replacement
• Hold pump pulley from turning by compressing drive
belt then loosen pump pulley bolts.
• Remove drive belt as outlined above then remove
pump pulley.
• Install pump pulley with retaining bolts hand tight.
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-EIECTRICAI 6Y-3
PERIODIC SERVICING
Since the Battery is a perishable item which requires
periodic servicing, a good maintenance program will
insure the longest possible Battery life.
COMMON CAUSES OF FAILURE
If the Battery tests good but fails to perform satis-
factorily in service for no apparent reason, the following
are some of the more important factors that may point to
the cause of the trouble.
1.
Vehicle accessories inadvertently left on overnight to
cause a discharged condition.
2.
Slow speed driving of short duration, to cause an
3.
undercharged condition.
A vehicle
capacity.
electrical load exceeding the generator
4.
Defect in the charging system such as high resist-
ance, slipping fan belt, faulty generator or voltage
regulator.
5. Battery abuse, including failure to keep the Battery
top clean, cable clamps and posts clean and tight,
and improper addition of water to the cells.
LEVEL INDICATOR
The Battery features an electrolyte level indicator,
which is a specially designed vent plug with a transparent
rod extending through the center (fig. 5b). When the elec-
trolyte is at the proper level, the lower tip of the rod is
immersed, and the exposed top of the rod will appear
very dark; when the level falls below the tip of the rod,
the top will glow. ,
The Indicator reveals at a glance if water is needed,
without the necessity of removing the vent plugs (fig. 6b).
The Level Indicator is used in only one cell (second
cell cap from positive Battery post) because when the
electrolyte level is low in one cell, it is normally low in
all cells. Thus when the Indicator shows water is needed,
check the level in all six cells.
An alternate method of checking the electrolyte level is
to remove the vent plug and visually observe the electro-
lyte level in the vent well. The bottom of the vent well
features a split vent which will cause the surface of the
electrolyte to appear distorted when it makes contact.
The electrolyte level is. correct when the distortion first
appears at the bottom of the split vent (fig. 4b).
ELECTROLYTE LEVEL
The electrolyte level in the Battery should be checked
regularly. In hot weather, particularly during trip driv-
ing, checking should be more frequent because of more
rapid loss of water. If the electrolyte level is found to be
low, then colorless, odorless, drinking water should be
added to each cell until the liquid level rises to the split
vent located in the bottom of the vent well. DO NOT
OVERFILL because this will cause loss of electrolyte
resulting in poor performance, short life, and excessive
corrosion.
CAUTION: During service only water should be
added to the Battery, not electrolyte.
The liquid level in the cells should never be allowed to
drop below the top of the plates, as the portion of the
INDICATOR
ELECTROLYTE LEVEL
CORRECT
Fig.
5b—Cut-Away View Showing Electrolyte at Proper Level
with Indicator Having Dark Appearance
plates exposed to air may be permanently damaged with a
resulting loss in performance.
WATER USAGE
Excessive usage of water indicates the Battery is being
overcharged. The most common causes of overcharge
are high Battery operating temperatures, too high a volt-
age regulator setting, poor regulator ground wire con-
nection. Normal Battery water usage is approximately
one to two ounces per month per battery.
INDICATOR
Fig.
6b—Cut-Away View Showing Electrolyte at Low Level
with Indicator Having Light Appearance
CHASSIS SBtVKZ MANUAL
ENGINE-ELECTRICAL 6Y-7
CHARGING SYSTEM
INDEX
Page
General Description . 6Y-7
Maintenance and Adjustments 6Y-9
Static Checks . 6Y-10
System Condition Check and Voltage
•Regular Adjustment. 6Y-10
General Output 6Y-11
Generator Diode and Field Test 6Y-12
Indicator Lamp-Initial Field Excitation
Circuit Tests . 6Y-12
Page
Field Circuit Resistance Wire Tests 6Y-13
Field Relay Test and Adjustment 6Y-14
Other Harness Checks 6Y-14
Service Operations 6Y-14
Generator 6Y-14
Removal and Installation 6Y-14
Pulley Replacement. 6Y-14
Brush Replacement (6" Delcotron). 6Y-15
Double Contact Regulator . . . . . . 6Y-16
GENERAL DESCRIPTION
The charging system includes the battery, generator,
regulator, telltale light, and necessary wiring to connect
these components. The Delcotron is offered as standard
equipment, although there are various capacities avail-
able on all models.
The Delcotron continuous output A.C. generator (fig.
lc) consists of two major parts, a stator and a rotor. The
stator is composed of a large number of windings as-
sembled on the inside of a laminated core that is attached
to the generator frame. The rotor revolves within the
stator on bearings located in each end frame. Two
brushes are required to carry current through the two
slip rings to the field coils wound concentric with the
shaft of the rotor. Six rectifier diodes are mounted in the
slip ring end frame and are joined to the stator windings
at three internally located terminals.
Diodes are mounted in heat sinks to provide adequate
heat dissipation. The six diodes replace the separately
mounted rectifier as used in other types of application.
The diodes change the Delcotron A.C. current to D.C.
current.
Two regulators (fig. 2c) are available on the 1967 vehi-
cles,
a double contact two unit type and a transistor
regulator. The function of these regulators in the charg-
ing system is to limit the generator voltage to a pre-set
value by controlling the generator field current. Both
regulators have an internal field relay unit. The relay
unit allows the telltale lamp to light (as a bulb check)
with the ignition key on and engine not running. When the
engine is started and the generator begins to charge, the
indicator light goes out indicating that the system is op-
erating normally.
The double contact regulator, when used with the
special 63 amp air conditioning model generator (4 ohm
field coil) uses a field discharge diode internally in the
field circuit (figs. 3c and 4c). The added diode adapts the
BRUSH AND
TERMINAL
ASSEMBLY
SLIP RINGS
SLIP RING
END FRAME
_\
THRU
BOLT
DRIVE END
FRAME
BEARING
BEARING
DIODES
ROTOR
5.5" SERIES ID DELCOTRON
STATOR
ASSEMBLY
GREASE
RESERVOIR
BRUSH
FAN ASSEMBLY
6.2" SERIES 2D TYPE 150 DELCOTRON
Fig.
lc—Delcotron Cross-section View
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-9
63 AMP 1
MODELS ONLY'
BATTERY FUSIBLE
LINK
HORN
FUSIBLE LINK'
TRANSISTOR
FUSIBLE LINK'
Fig.
4c— Circuitry - Voltage Regulator Assemblies (Corvette)
Engine compartment wiring harness incorporates sev-
eral fusible links. Each link is identified with its gage
size. A fusible link is a length of special wire (normally
four wire gages smaller than the circuit it is protecting)
used in wiring circuits that are not normally fused, such
as the ignition circuit. The same size wire with a hypalon
insulation must be used when replacing a fusible link.
The links are:
1.
The pigtail lead at the battery positive cable (except
Corvette) is a 14 gage, brown fusible link protecting
the 10 gage battery charging circuit. This wire is an
integral part of the battery cable assembly and serv-
icing requires replacing the complete battery cable
assembly. On Corvette models this link is installed
as a molded splice at the solenoid "Bat" terminal
and servicing requires splicing in a new link.
2.
A 16 gage black fusible link is located at the horn
4.
relay to protect all unfused wiring of 12 gage or
larger. It is installed as a molded splice and serv-
icing requires splicing in a new link.
The generator warning light and field circuitry (16
gage wire) is protected by a fusible link (20 gage
orange wire) used in the "battery feed to voltage
regulator #3 terminal" wire. The link is installed as
a molded splice in the generator and forward lamp
harness and is serviced by splicing in a new 20 gage
wire as required.
The ammeter circuit on all models is protected by
two orange, 20 gage wire fusible links installed as
molded splices in the circuit at the junction block or
the solenoid "Bat" terminal (Corvette only) and at
the horn relay. Each link is serviced by splicing in a
new 20 gage wire as required.
MAINTENANCE AND ADJUSTMENTS
At regular intervals, inspect the terminals for cor-
rosion an4 loose connections, and the wiring for frayed
insulation. Check mounting bolts for tightness. Check the
drive belt for alignment, proper tension and wear. Be-
cause of the higher inertia and load capacity of the rotor
used in A.C. generators, PROPER BELT TENSION is
more critical than on D.C. generators.
Since the Delcotron and its companion regulator are
designed for use on negative polarity systems only, the
following precautions must be observed. Failure to ob-
serve these precautions may result in serious damage to
the charging system.
1.
When installing a battery, always make absolutely
sure the ground polarity of the battery, generator and
regulator is the same.
2.
When connecting a booster battery, make certain to
connect the correct battery terminals together.
3.
When connecting a charger to the battery, connect the
correct charger leads to the battery
%
terminals.
4.
Never operate the generator on an uncontrolled open
TO SOLENOID
BAT ACC RES. WIRE
Fig.
5c—Typical Wiring Diagram Showing Lead Connections
CHEVROLET CHASSIS SERVICE MANUAL