
ENGINE-ELECTRICAL-6Y-30
Fig.
2 li—Removing Ignition Switch Nut
4.
Remove heater and/or A/C control panel assembly
retaining screws and push panel assembly from
console.
NOTE: If interference between control panel
and radio is encountered, loosen radio retaining
nuts.
5.
Remove radio control knobs, bezels and retaining
nuts.
6. Disconnect radio wiring harness and antenna lead-in.
7.
Remove radio rear brace attaching screw and re-
move radio from vehicle.
Fig.
231—Switch and Connector Unplugged
8. Remove ignition switch bezel nut using Tool J-7607
and push switch rearward from panel opening.
9. Disconnect wiring connector from rear of switch.
10.
To install, reverse removal procedure.
SPARK PLUGS
CLEANING AND REGAPPING
Clean the spark plugs thoroughly, using an abrasive-
type cleaner. If the porcelains are badly glazed or
blistered, the spark plugs should be replaced. All spark
plugs must be of the same make and number or heat
range. Use a round feeler gauge to adjust the spark plug
gap to specifications (fig. 24i).
Fig.
22i—Unlocking Ignition Switch Connector
Fig.
241—Setting Sfxirk Plug Gap
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL
6Y-31
CAUTION: Before adjusting gap, me center
INSTALLATION
electrode flat. In adjusting the spark pluig Install the spark plugs in the engine with new gaskets
gap,
never bend the center electrode which and tighten to specifications. If torque wrench is not
extends through the porcelain center. Always available, tighten plugs finger tight and 1/2 turn more.
make adjustment by bending the ground or , Plugs are of a 14 millimeter size and care must be
side electrode. exercised when installing or the gap setting may be
changed.
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-32
STARTER CIRCUIT
INDEX
Page
General Description 6Y-32
Maintenance and Adjustments . '. . 6Y-32
Resistance Checks 6Y-32
Starting Motor and Solenoid Check 6Y-33
Page
Service Operations 6Y-33
Starter Motor 6Y-33
Removal and Installation 6Y-33
GENERAL DESCRIPTION
The function of the starting system, composed of the
starting motor, solenoid and battery, is to crank the
engine. The battery supplies the electrical energy, the
solenoid completes the circuit to the starting motor, and
the motor then does the actual work of cranking the
engine.
The starting motor (fig. Is) consists primarily of the
drive mechanism, frame, armature, brushes, and field
windings. The starting motor is a pad mounted 12-volt
extruded frame type, having four pole shoes and four
fields,
connected with the armature. The aluminum drive
end housing is extended to enclose the entire shift lever
and plunger mechanism, protecting them from dirt,
splash, and icing. The flange mounted solenoid switch
operates the overrunning clutch drive by means of a
linkage to the shaft lever.
The V-8 wiring harness differs from the in-line engine
in that the ignition lead to the coil from the switch is at-
tached at the coil instead of at the starter solenoid (fig.
2s).
CONTACT
FINGER
PINION
STOP
BRUSH
INSULATED BRUSH HOLDER \ FIELD COIL
BRUSH SPRING ARMATURE
GROUNDED BRUSH HOLDER
OVERRUNNING
CLUTCH
Fig.
Is—Starting Motor Cross Section (Typical)
MAINTENANCE AND ADJUSTMENTS
No periodic lubrication of the starting motor or sole-
noid is required. Since the starting motor and brushes
cannot be inspected without disassembling the unit, no.
service is required on these units between overhaul
periods.
RESISTANCE CHECKS
Although the starting motor cannot be checked against
specifications on the car, a check can be made for. exces-
sive resistance in the starting circuit. Place a volt-
meter across points in the cranking circuit as outlined
below and observe the reading with the starting switch
closed and the motor cranking (distributor primary lead
grounded to prevent engine firing).
1.
From battery positive post To solenoid battery
terminal.
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-33
O
V-8 ENGINE
STARTING MOTOR
Fig.
2s—V-8 Starting Circuit Diagram
2.
3.
From battery negative post
To
starting motor
housing.
From solenoid battery terminal
To
solenoid motor
terminal.
If voltage drop
in
any
of
above check exceeds 0.2 volts,
excessive resistance
is
indicated in that portion
of
start-
ing circuit
and the
cause
of the
excessive resistance
should
be
located
and
corrected
in
order to obtain maxi-
mum efficiency in the circuit.
CAUTION:
Do not
operate
the
starting motor
continuously
for
more than
30
seconds
to
avoid
overheating.
When
the
solenoid fails
to
pull
in, the
trouble may be
due
to
excessive voltage drop in the solenoid control cir-
cuit.
To
check
for
this condition, close
the
starting
switch
and
measure
the
voltage drop between
the
BAT-
TERY terminal of the solenoid and the
SWITCH (S)
termi-
nal
of
the solenoid.
1.
If
this voltage drop exceeds 3.5 volts, excessive
re-
sistance
in the
solenoid control circuit
is
indicated
and should be corrected.
2.
If the
voltage drop does not exceed 3.5 volts and the
solenoid does not pull in, measure the voltage availa-
ble
at
the SWITCH terminal
of
the solenoid.
3.
If the
solenoid does
not
feel warm,
it
should pull
in
whenever the voltage available
at
the SWITCH termi-
nal
is 7.7
volts
or
more. When
the
solenoid feels
warm,
it
will require
a
somewhat higher voltage
to
pull in.
STARTING MOTOR AND SOLENOID CHECK
The following checks
may be
made
if the
specific
gravity of the battery
is
1.215
or
higher.
1.
If the
solenoid does
not
pull in, measure the voltage
between
the
switch
(S)
terminal
of the
solenoid
and
ground with the starting switch closed.
CAUTION:
If the
solenoid feels warm, allow
to
cool before checking.
If
the
voltage
is
less than 7.7 volts, check for ex-
cessive resistance
in the
solenoid control circuit.
If
the
voltage exceeds 7.7 volts, remove the starting
motor
and
check
(1)
solenoid current draw,
(2)
starting motor pinion clearance,
and (3)
freedom of
shift lever linkage.
2.
If
the solenoid "chatters" but does not hold in, check
the solenoid
for an
open "hold-in" 'winding. When-
ever
it is
necessary
to
replace
a
starting motor
solenoid, always check starting motor pinion
clearance.
3.
If
motor engages
but
does
not
crank
or
cranks
slowly, check
for
excessive resistance
in the ex-
ternal starting circuit, trouble within
the
starting
motor,
or
excessive engine resistance
to
cranking.
SERVICE OPERATIONS
STARTING MOTOR
REMOVAL AND INSTALLATION (Fig.
3s)
The following procedure
is a
general guide
for all
vehicles
and
will vary slightly depending
on
series
and
model.
1.
Disconnect battery ground cable at battery.
2.
Raise vehicle
to a
good working height.
3.
Disconnect all wires
at
solenoid terminals.
NOTE: Reinstall
the
nuts
as
each wire
is
dis-
connected
as
thread size
is
different but may be
mixed and stripped.
4.
Loosen starter front bracket (nut on V-8 and bolt on
L-6) then remove two mount bolts.
5.
Remove
the
front bracket bolt
or nut and
rotate
bracket clear
of
work area then lower starter from
vehicle
by
lowering front end first
—
(hold starter
against bell housing
and
sort
of
roll end-over-end).
6. Reverse
the
removal procedure
to
install. Torque
the mount bolts
to
25-35
ft.
lbs. first, then torque
brace bolt.
7.
Check operation
of
starter on vehicle.
Fig.
3s—Starter Mounting
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-34
SPECIAL TOOLS
J-7607
IGNITION SWITCH
NUT REMOVER
J-9717-2
SUPPORT
TOOL
J-9717-1
PRESS
TOOL
J-9600-2
SHOULDERED
INSTALLER
J-21501
PULLY
ADAPTER
J-5184
CHECKING
SCALE
J-21600
HARNESS ADAPTER
Fig. 4s-Specia! Tools
CHEVROLET CHASSIS SERVICE MANUAL

SECTION 7
CLUTCH AND TRANSMISSIONS
CONTENTS OF THIS SECTION
Clutch
Three-Speed . . .
Overdrive
Three-Speed, (Warner T-16)
Four-Speed (Muncie) . . . .
Page
7-1
7-6
7-9
7-14
7-16
CLUTCH
Page
Four-Speed (Saginaw) 7-20
Powerglide 7-23
Turbo Hydra-Matic 7-36
Special Tools 7-43
INDEX
General Description
Maintenance and Adjustments
Linkage Inspection
Clutch Linkage Adjustment
Component Parts Replacement
Clutch Assembly ......
Removal from Vehicle .
Page
7-1
7-1
7-1
7-2
7-3
7-3
7-3
Installation in Vehicle
Clutch Pedal ..'....,
Clutch Cross Shaft . . .
Removal.......
Repairs
Installation .....
Page
7-4
7-4
7-4
7-4
7-4
7-4
GENERAL DESCRIPTION
A diaphragm spring-type clutch assembly is used with
manual transmissions.
The clutch assembly is enclosed in a 360° bell housing
which must be removed to gain access to the clutch.
V-8 engines (equipped with a 4 speed transmission)
use a bent-finger, centrifugal diaphragm type clutch as-
sembly. All its integral release fingers are bent back to
gain a centrifugal boost and to insure quick re engagement
at high engine speeds.
This type of clutch has the advantages of increasing
pressure plate load as the driven plate wears, and of low
pedal effort with high plate loads without requiring over-
center booster springs on the clutch linkage.
The pressure plate is a high tensile strength iron de-
signed for maximum speed conditions.
The clutch release bearing (fig. 4), used with the bent
finger diaphragm clutch, has an overall length of approxi-
mately
1-1/4".
The longer bearing, used with the straight
diaphragm, will cause inability to obtain free pedal travel,
especially as the clutch wears, resulting in slippage and
rapid wear.
DO
NOT INTERCHANGE!
The clutch is operated by conventional linkage consist-
ing of two groups, upper linkage and lower linkage.
The return spring pre-loads clutch linkage, removing
looseness due to wear. The clutch free pedal travel,
therefore, will increase with linkage wear and decrease
with driven disc wear, and free travel felt at pedal is
throwout bearing lash.
MAINTENANCE AND ADJUSTMENTS
LINKAGE INSPECTION
There are several things which affect good clutch op-
eration. Therefore, it is necessary, before performing
any major clutch operations, to make preliminary in-
spections to determine whether trouble is actually in the
clutch.
Check the clutch linkage to be sure the clutch releases
fully as follows:
1.
With engine running, hold the clutch pedal approxi-
mately 1/2" from floor mat and move shift lever be-
tween first and reverse several times. If this can be
done smoothly, the clutch is fully releasing. If shift
is not smooth, clutch is not fully releasing and ad-
justment is necessary.
2.
Check clutch pedal bushings for sticking or excessive
wear.
3.
Check fork for proper installation on ball stud. Lack
of lubrication on fork can cause fork to be pulled off
the ball.
4.
Check for bent, cracked or damaged cross shaft
levers or support bracket.
5.
Loose or damaged engine mounts may aUiow the en-
gine to shift its position causing a bind on clutch
linkage at the cross shaft. Check to be sure there is
Fig.
1 - Chevrolet Clutch Pedal Free Travel Adjustment
CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-2
Fig.
2 - Chevelle Clutch Pedal Free Travel Adjustment (V-8 Shown)
some clearance between cross shaft and both its
mounting brackets.
CLUTCH LINKAGE ADJUSTMENT
There is one linkage adjustment (clutch fork push rod
or pedal push rod) to compensate for all normal clutch
wear.
The clutch pedal should have
1-1/4"
free travel (meas-
ured at clutch pedal pad) before the throwout bearing en-
gages the clutch diaphragm spring levers. Lash is re-
quired to prevent clutch slippage which would occur if the
bearing was held against the fingers and to prevent the
bearing from running continually until failure.
Chevrolet Linkage Adjustment (Fig. 1}
With Nuts (A) & (B) loose on Rod (D)
&
before installa-
tion of Clutch Pedal Return Spring
(E),
apply approximately
5 lbs. load in direction of arrow (F) to eliminate clear-
ance between throwout bearing and clutch fingers. Move
Rod (D) in direction of arrow (G) until Clutch Pedal Arm
makes contact with Bumper Stop on instrument panel
brace. Run Nut (B) toward Swivel until dimension (X) is
9/32". Tighten Nut (A) to lock Swivel (C) against Nut (B).
Install Clutch Pedal Return Spring (E).
The foregoing procedure will provide a free pedal
travel of 1" to
1-1/2"
measured on a perpendicular from
the crown of the, pedal pad to the bare metal toe pan.
Chevelle Linkage Adjustment (Fig. 2)
1.
Disconnect spring between cross shaft lever and
clutch fork.
2.
Loosen push rod locknut about three turns.
3.
If there is no free travel, shorten the rod (by turning
at square wrench area) until it is free of clutch fork.
4.
Hold the clutch fork rearward to move throwout
lightly against clutch release fingers, then adjust rod
length until rod just touches ,its seat in the fork.
5.
Adjust locknut to obtain approximately 3/16" clear-
ance between nut and rod sleeve end.
6. Turn the rod with wrench, until the nut just comes in
contact with rod sleeve end, then hold the rod with
wrench and tighten locknut.
7.
Check free pedal travel at pedal (1" to
1-1/2"
is
proper clearance). Readjust if necessary.
Chevy II Linkage Adjustment (Fig. 3}
L-4 & L-6 Models
1.
Loosen locknut "A" and lengthen or shorten push rod
in swivel as required by turning with wrench on ma-
chined flat "B". (Shorten push rod to increase pedal
lash).
2.
Hold push rod at flat "B" and tighten locknut "A".
3.
Recheck pedal free travel.
NOTE: A measurement of approximately 3/16"
between push rod and its seat in fork will give
required pedal free travel.
V-8 Models
The eight cylinder linkage has a two-piece clutch fork
push rod (fig. 3). Adjust clutch pedal free travel by turn-
ing the adjusting rod portion of the push rod to obtain apr
proximately 3/16" clearance between clutch fork and end
of rod, ttien tighten locknut to 8-12 lbs. ft. and check free
travel at pedal. Pedal free travel on all models should
be 1" to
1-1/2".
Corvette Linkage Adjustment
Refer to fig. 1 and the following procedure:
1.
Disconnect pedal return spring.
2.
With Nuts (A) and (B) loose on Rod (D) apply push
hard load in direction of arrow (F) to eliminate
clearance between throwout bearing and clutch
fingers.
3.
Run Nut (B) towards Swivel (C) until dimension (X)
is 3/8" to 7/16".
4.
Tighten Nut (A) to lock swivel against Nut (B).
5.
Connect pedal return spring and check pedal free
travel for
1-1/4"
minimum to 2" maximum.
6. Check every 3,000 miles.
7.
Adjust free travel to 2" to 2-1/2" for heavy duty op-
eration. The return spring may be removed for
heavy duty conditions.
Camaro Linkage Adjustment
Refer to Figure 4 and the following procedure:
Apply a 10 lb. load in direction of Arrow (E) to hold
Clutch Pedal against Clutch Pedal Bumper.
Apply a 10 lb. load to Clutch Fork in direction of Arrow
(D) to eliminate clearance between throwout bearing and
clutch fingers.
Insert a .198 Spacer (F) between clutch fork and Ad-
justing Rod (A).
Rotate Adjusting Rod against Spacer until it has a 5 in.
lb.
torque.
Hold Adjusting Rod and tighten Nut (C) against Swivel
(B) or Rod (B).
Remove Spacer. Install return spring and extension to
clutch fork.
Pedal will have approximately 1" to
1-1/8"
free travel.
A clutch that has been slipping prior to free play ad-
justment may still slip right after the new adjustment due
CHEVROLET CHASSIS SERVICE MANUAL

CLUTCH AND TRANSMISSIONS 7-3
•BUMPER
CLUTCH FORK
CLUTCH PEDAL
L-4 AND L-6 MODELS
Fig.
3 - Chevy II Clutch Pedal Free Travel Adjustment
to previous heat. The vehicle should be returned to the
Dealership the next day (at least 12 hours) to give clutch
time to cool to normal temperatures. Any slippage
should then be evaluated as follows:
1.
Drive in high gear at 20-25 MPH.
2.
Depress clutch pedal to the floor and rev engine to
2500-3500 rpm.
3.
Engage clutch quickly (snap foot off pedal) and press
accelerator to full throttle.
Engine speed should drop noticeably then accelerate
with vehicle. If clutch is bad, the engine speed will in-
crease.
NOTE: Do not repeat more than once or clutch
, will overheat.
-NUTC NUTC
SPACER F
SPACER F
RODB
' CLUTCH^ SWIVEL B
FORK
ADJUSTING
ROD
A '
V8 ENGINE
ADJUSTING
ROD
A
L6 ENGINE
Fig.
4 - Clutch Pedal Free Travel Adjustment
COMPONENT PARTS REPLACEMENT
CLUTCH ASSEMBLY
Removal From Vehicle
1.
Support engine and remove transmission as outlined
in transmission section.
2.
Disconnect clutch fork push rod and spring.
3.
Remove flywheel housing.
4.
Slide clutch fork from ball stud and remove fork from
dust boot.
NOTE: Ball stud is threaded into clutch hous-
ing and is easily replaced, if necessary.
CHEVROLET CHASSIS SERVICE MANUAL