
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

AIR INJECTOR REACTOR SYSTEM
6T-2
AIR
MANIFOLD
MIXTURE
CONTROL
VALVE
AIR
INJECTION
PUMP
IN LINE
MIXTURE
CONTROL
VALVE
AIR INJECTION
PUMP
CHECK
VALVE
V8
Fig.
I—Air
Injection Reactor System (Typical)
• Install
and
adjust drive belt
as
outlined above.
• Hold pump pulley from turning
by
compressing drive
belt then torque pump pulley bolts
to 25 ft. lbs.
• Recheck drive belt tension
and
adjust
if
required.
Air Manifold, Hose and Tube
Inspection (Fig. 4)
• Inspect
all
hoses
for
deterioration
or
holes.
• Inspect
all
tubes
for
cracks
or
holes.
PUMP
HOUSING
91
DRIVE V
HUB
PRESSURE
RELIEF VALVE
•H
PUMP
'
Mm ^
COVER
A.
J^HTEXHAUST
wBBE
TUBES
SB
^1 INTAKE
JH TUBE
• Check
all
hose and tube connections.
• Check
all
tube
and
hose routing. Interference
may
cause wear.
•
If a
leak
is
suspected
on the
pressure side
of the
system
or any
tubes and/or hoses have been discon-
nected
on the
pressure side,
the
connections should
be checked
for
leaks with
a
soapy water solution.
With
the
pump running, bubbles will form
if
aleak
exists.
Replacement
•
To
replace
any
hose and/or tube, note routing then
remove hose(s) and/or tube(s)
as
required.
CAUTION:
The 1/4"
pipe threads
at the
cylin-
der head
(In
Line)
or
exhaust manifold
(V8) are
VALVE
IN
OPEN
POSITION
INLET
VALVE
IN
CLOSED
POSITION
DIAPHRAGM
POSITIONS
SIGNAL
LINE
CONNECTION
ALVE
Fig.
2—Air Injection Pump
Fig.
3—Mixture Control Valve
CHEVROLET CHASSIS SERVICE MANUAL

AIR INJECTOR REACTOR SYSTEM 6T-4
Air injection Tube
Inspection (Fig. 5)
• There is no periodic service or inspection for the
air injection tubes, yet on In Line engines whenever
the cylinder head is removed or on V8 engines when-
ever the exhaust manifolds are removed, inspect the
air injection tubes for carbon build up and warped or
burnt tubes.
• Remove any carbon build up with a wire brush.
• Warped or burnt tubes must be replaced.
Replacement
• On In Line engines remove carbon from tubes and
using penetrating oil, work tubes out of cylinder
head.
• On V8 engines clamp exhaust manifold in a vise,
remove carbon from tubes and using penetrating oil,
work tubes out of manifold.
• Install new tubes in cylinder head or manifold.
Air Injection Pump
Inspection
Accelerate engine to approximately 1500 KPM and
observe air flow from hose.Osf). If air flow increases as
engine is accelerated, pump is operating satisfactorily.
If air flow does not increase or is not present, proceed
as follows:
• Check for proper drive belt tension.
• Check for a leaky pressure relief valve. Air maybe
heard leaking with the pump running.
NOTE:
The Air Injection Reactor System is
not completely noiseless. Under normal condi-
tions noise rises in pitch as engine speed in-
creases. To determine if excessive noise is the
fault of the Air Injection Reactor System, oper-
ate the engine with the pump drive belt removed.
IN LINE
INJECTION
si
AIR AAANIFOLD^
ASSEMBLY
AIR MANIFOLD
ASSEMBLY ^S
~jk
VALVE
V-8
ff
>yi
INJECTION
» TUBE
' ,•
Fig.
5—Air Injection Tube (Typical)
Fig.
6-HRemoving Pressure Relief Valve
If excessive noise does not exist with the belt
removed proceed as follows:
Check for proper installation of relief valve silencer
on L-6 and 283, 327, 350 cu. in. V-8 engines.
Check for a seized Air Injection Pump.
Check hoses, tubes, air manifolds and all connec-
tions for leaks and proper routing.
Cheqk carburetor air cleaner for proper installation.
Check air injection pump for proper mounting.
If none of the above conditions exist and the air in-
jection pump has excessive noise remove then repair
as outlined in the Overhaul Manual.
Replacement
Disconnect,
t&e
hoses at the pump.
Remove pump pulley as outlined.
Remove pump mounting bolts and remove pump.
Install pump with mounting bolts loose.
Install pump pulley as outlined.
Install and adjust belt as outlined.
Connect the hoses at the pump.
Pressure Relief Valve Replacement
1.
Using J-7055-5 and J-6585 pull relief valve from
housing (fig. 6).
2.
Using a 15/16" socket tap the relief valve into hous-
ing until the valve shoulders on the housing (fig. 7).
CAUTION: Use extreme care to avoid distort-
ing housing.
NOTE:
Various length pressure setting plugs
(fig. 8) designed for the particular requirements
of vehicle - engine combinations, determine the
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-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

ENGINE-ELECTRICAL 6Y-10
circuit. Make absolutely certain all connections in
the circuit are secure.
5.
Do not short across or ground any of the terminals
on the generator or regulator.
6. Do not attempt to polarize the generator.
7.
Do not disconnect lead at generator without first dis-
connecting battery ground cable.
Trouble in the A.C. charging system will usually be
indicated by one or more of the following conditions:
1.
Faulty indicator lamp or ammeter operation.
2.
An undercharged battery (usually evidenced by slow
cranking speeds).
3.
An overcharged battery (usually evidenced by exces-
sive battery water usage).
4.
Excessive generator noise or vibration.
Described below are a series of on-the-vehicle quick
checks which are designed to assist the service tech-
nician in locating troubles within the various components
of the engine electrical system. Additional checks, ad-
justments and overhaul procedures of these components
are also described in the "Charging Systems—Service
Operations Section" and should be referred to as
necessary.
STATIC CHECKS
Before making any electrical checks, perform the fol-
lowing static checks:
1.
Check for loose fan belt.
2.
Check for defective battery. (Refer to Battery).
3.
Inspect all connections, including the slip-on con-
nectors at the regulator and Delcotron.
NOTE: Do not short field to ground to check if
generator is charging since this will seriously
damage the charging system.
SYSTEM CONDITION TEST
This test is used .to indicate the overall condition of the
charging system (both good and defective) and to isolate
the malfunctioning unit if the system is defective.
NOTE: On Corvette models difficulty may be
encountered -when attempting to make the re-
quired test connections at the voltage regulator.
It is advisable to remove the regulator from its
mounting location to perform the necessary con-
nections at the regulator for the following tests
but make sure unit is grounded.
1.
With ignition off, perform the prescribed Static
Checks outlined in this section. Then set hand brake
and shift transmission
into
neutral.
2.
Connect a voltmeter from junction block relay to
ground at regulator base.
CAUTION: Be sure meter clip does not touch a
resistor or terminal extension under regulator,
3.
Connect a tachometer on engine.
4.
Models equipped with Indicator Lamp: Turn ignition
switch on "ON" position and check indicator lamp.
If lamp fails to glow, perform appropriate tests and
corrections (Indicator Lamp Circuit Tests) before
continuing.
Models equipped with Ammeter: Turn ignition
switch to "ACC" with an accessory on and check
ammeter. If ammeter fails to read discharge, check
ammeter circuit before continuing.
5.
Models equipped with Indicator Lamp: If lamp glows,
start the engine and run' it at 1500 rpm or above.
Check indicator lamp. If lamp fails to go out, per-
form appropriate test and corrections (Indicator
Lamp Circuit Test) before continuing.
Models equipped with Ammeter: If ammeter reads
discharge, start the engine and observe ammeter. If
meter fails to move toward charge (from original
position), perform appropriate test and corrections
(Field Circuit Tests) before continuing.
NOTE: At this point a field circuit has been
established and any other problem will lie in
generator or regulator.
6. Turn on high-beam headlights and heater blower
motor to high speed, run engine at or above 1500
rpm (for a few minutes, if necessary) and read the
voltage on meter.
AIR GAP
ADJUSTING NUT
ONLY
ADJUSTING SCREW
(Turn To Adjust
Voltage Setting)
Fig.
6c—Adjusting Voltage Setting
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-13
F 2 3 4
f 2 3 4
F 2 3 4
Fig.
10c—Initial Field Excitation Circuit Tests
connect to "F" terminal on Delcotron (fig. 10c,
Step 3), and note lamp:
a. Lamp glows-an open circuit in wire between "F"
terminals—correct as needed.
b.
Fails to glow—Delcotron field has open circuit,
see "Service Operations" to repair %
If Lamp Fails to Go Out, or if Ammeter Shows
Discharge the Possible Causes are:
1.
Loose drive belt—adjust as necessary.
2.
Faulty field relay—(see relay test and adjustment).
3.
Defective Delcotron—(see Delcotron output test).
4.
At normal idle—parallel resistance wire open (see
Resistance test). On ammeter models the initial
field excitation wire to "ACC" terminal is open.
5. Switch off—positive diode shorted (see Diode test).
FIELD CIRCUIT RESISTANCE
WIRE CHECKS
The resistance wire is an integral part of the ignition
harness. However, the resistance wire is not solderable;
it must be spliced with a crimp-type connector. It is
rated at 10 ohms, 6.25 watts minimum.
The check for an open resistor or field excitation wire
(connected to the ignition switch "ACC" terminal) is as
follows:
1.
Connect a test lamp from the wiring harness con-
nector terminal "4" to ground as shown in Figure
10c (Step 1).
2.
Turn the ignition switch to the "ON" position and
note test bulb.
a. Test lamp glows—resistance is O.K.
b.
Test lamp does not glow—the resistor is open
circuited—note also that dash lamp does not glow
during this test because series resistance of the
2 bulbs causes amperage to be too low.
VOLTMETER
3 4
WIRING*
HARNESS
CONNECTOR
Fig.
11c—Testing Field Relay
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-14
VOLTMETER
WIRING HARNESS
CONNECTOR
Fig.
12c—Field Relay Closing Voltage Test
FIELD RELAY CHECKS AND ADJUSTMENT
To check for a faulty relay proceed as follows:
1.
Connect a voltmeter into the system at the regulator
No.
2 terminal to ground (fig. lie).
2.
Operate the engine at fast idle (1500 to 2000 rpm) and
observe voltmeter reading.
3.
If voltmeter shows zero voltage at regulator, check
circuit between No. 2 terminal on regulator to "R"
terminal on Delcotron.
4.
If voltage at regulator exceeds closing voltage
Fig.
13c—Adjusting Field Relay Closing Voltage
specification and light remains on, regulator field
relay is faulty (Refer to specifications). Check and
adjust regulator as follows:
CLOSING VOLTAGE ADJUSTMENT
•1.
Make connections as shown in Figure 12c using a 50
ohm variable resistor.
NOTE: This gives us a variable resistance in
series from a hot lead to the relay coil.
2.
Turn resistor to "open" position.
3.
Turn ignition switch off.
4.
Slowly decrease resistance and note closing voltage
of the relay. Adjust by bending heel iron in the man-
ner illustrated in Figure 13c.
OTHER HARNESS CHECKS
Other wires in the charging system harness need be
checked for continuity by use of an ohmmeter or a test
ligjit (12 Volt). Connect the test so the wire in question is
in series in the test circuit.
SERVICE OPERATIONS
Service Procedures described in this section are for
the 5.5" aluminum and 6.2" perforated stator Delcotrons
(fig. 14c). Where important differences are encountered
separate mention will be made of the two generators.
GENERATOR
REMOVAL AND INSTALLATION
1.
Disconnect the battery ground strap at battery to
prevent damaging diodes.
2.
Disconnect wiring leads at Delcotron.
3.
Remove generator brace bolt, (if power steering
equipped, loosen pump brace and mount nuts) then
detach drive belt (belts).
4.
Support the generator and remove generator mount
bolt (6.2" Delcotron uses 2 mount bolts) and remove
from vehicle.
5.
Reverse the removal procedure to install then adjust
drive belt.
PULLEY REPLACEMENT
5.5" Delcotron
Single Groove Pulley
1.
Place 15/16" box wrench on retaining nut and insert
a 5/16" alien wrench into shaft to hold shaft while
removing nut (fig. 15c).
2.
Remove washer and slide pulley from shaft.
3.
Reverse Steps 1 and
2
to install, use a torque wrench
with a crow-foot adapter (instead of box wrench) and
torque the nut to 50 ft. lbs. (fig. 16c).
Double Groove Pulley
1.
Place a 15/16" socket (with wrench flats on the drive
CHEVROLET CHASSIS SERVICE MANUAL