
CORVETTE BODY 1B-32
1.
Panel - Underbody
2.
Panel - Wheel Housing
Closing - Right Hand
3. Shield - Right Hand Splash
4.
Nut
5. Panel - Underbody Closing
Fig.
68—Underbody Construction
6. Shield - Left Hand Splash
7. Nut
8. Reinforcement - Body
Mounting
9. Panel - Wheel Housing Closing
- Left Hand
10.
Plate - Seat Belt Mounting
11.
Bracket - Center Cover
Mounting
12.
Plate - Transmission Control
Boot Retaining
the broken or cracked portion. Side of "V" should
have a shallow pitch for maximum bonding surface.
A belt sander with a vacuum attachment will mini-
mize the dust problem, Figure 75.
4.
If rear of damage is accessible, use a button-type
repair. Clean back of area to permit the use of
laminate (resin-saturated glass-cloth) on both sides
of damaged area.
5. Cut fiberglass cloth to size. Make certain a minimum
of five layers is cut for the average repair.
6. Mix resin and hardener, 1 part hardener to 4 parts
resin. Add Thixatrope to the mix to give the mix
body and reduce the "runniness" of the material.
CAUTION: Cleanliness is most important. Be
certain all containers are dry and clean and
the resin and hardener cans are kept closed
when not in use. Do not use waxed cups for
mixing and do not allow resin to enter hardener
can or vice versa.
7. Saturate layers of fiberglass (fig. 76). Place lami-
nate over damage area. Smooth out wrinkles and
make sure general contour of area is maintained,
Figure 77.
8. Apply heat to repair area. Heat lamps are recom-
mended, used at least 12" away from repair. Allow
.15 to 20 minutes curing time. Trim repair to shape
at gel stage.
9. After the repair is cured, grind, file or sand to
contour. Files other than body files may be more
suitable. A belt sander with a vacuum cleaner at-
tachment will minimize the dust problem. Feather
edge and finish sand.
NOTE:
After Resin Repair, small pits or ir-
• regularities may appear in finished surface.
Imperfections should be repaired using the
Plastic Solder Repair Kit.
SPECIFIC REPAIRS
Scratched Panels, Spot Refinishing
In many instances, a scratched panel will involve only
a paint refinishing job. Figure 78 shows the top of a
fender panel which has been scratched through to the
plastic.
CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-27
CHEVELLE
, CHEVY II AND CAMARO SHOWN
1.
Caliper Belts
2.
Bleeder Valve
3. Caliper Half
4.
Piston Spring
Fig.
39-Caliper Assembly-Exploded View
5. Seal
6. Piston
7. Piston Boot
8. Brake Shoes
9. "O" Ri
10.
Caliper
11.
Retaining Pin
12.
Cotter Pin
caliper. Two retaining pins must be removed on
heavy duty Corvette front calipers. Identify the
inboard and outboard shoe if they are to be reused.
5. Remove the end of brake hose at bracket by re-
moving U-shaped retainer from the hose fitting and
withdrawing the hose from bracket.
6. Remove the caliper assembly from the mounting
bracket by removing two hex head bolts.
Disassembly (Fig. 39)
1.
Clean exterior of caliper with Declene, or equivalent.
On Chevrolet and Corvette front caliper, remove
brake hose.
2.
Separate the caliper halves by removing the two
large hex head bolts. Remove the two small "O"
rings from the cavities around the fluid transfer
holes in the two ends of the caliper halves.
3.
To free the piston boots so that the pistons may be
removed, push the piston down into the caliper
as far as it will go. Insert a screwdriver blade
under the inner edge of the steel ring in the boot,
and using the piston as a fulcrum, pry the boot from
its seat in the caliper
half.
CAUTION: Use care not to puncture seal when
removing pistons from caliper. ' ~
4.
Remove the pistons and piston springs from the
caliper
half.
Remove the boot and seal from their
grooves in the piston.
Cleaning and Inspection
1.
Clean all metal parts using Declene, or equivalent.
Remove all traces of dirt and grease. Do not use
mineral base solvents to clean brake parts.
2.
Using an air hose, blow out all fluid passages in the
caliper halves, making sure that there is no dirt
or foreign material blocking any of these passages.
3.
Discard all rubber parts. Boots, seals, and "O"
rings should be replaced with new service kit parts.
4.
Carefully inspect the piston bores in the caliper
halves. They must be free of scores and pits. A
scored or otherwise damaged bore will cause leaks
and unsatisfactory brake operation. Replace the
caliper half if either bore is damaged to the extent
that polishing with very fine crocus cloth will not
restore it.
CHEVROLET CHASSIS SERVICE MANUAL

SECTION 6
ENGINE
CONTENTS
OF
THIS SECTION
Page
Engine Tune Up
6-1
Torque Sequence
Engine Mechanical
(In
Line)
6-12
Special Tools
. .
Engine Mechanical (V8)
6-24
Page
6-39
6-40
ENGINE TUNE UP
INDEX
Page
General Description
. 6-1
Mechanical Checks and Adjustments
6-1
Spark Plug Removal
6-1
Test Compression
6-1
Service and Install Spark Plugs
6-2
Service Ignition System
6-3
Service Battery
and
Battery Cables
6-5
Service Delcotron
and
Regulator
6-5
Service
Fan
Belt
6-5
Service Manifold Heat Valve
6-5
Tighten Manifold
6-5
Service Fuel Lines
and
Fuel Filter ..........
6-6
Service Cooling System
6-6
Check and Adjust Accelerator Linkage
6-6
Service Crankcase Ventilation
6-6
Service
Air
Injection Reactor System
6-6
Choke Adjustment
6-7
Page
Instrument Cheek-Out
6-7
Instrument Hook-Up.
. 6*7
Check and Adjust Dwell
6-7
Check Dwell Variation
6-7
Check and Adjust Timing
6-8
Adjust Idle Speed
and
Mixture
6-8
Additional Checks and Adjustments
. 6-8
Testing Crankcase Ventilation Valve
. 6-8
Testing Cranking Voltage
6-8
Cylinder Balance Test
. 6-8
Battery
6-8
Ignition
; 6-8
Carburetor
6-11
Fuel Pump
6-11
Cooling System
. 6-11
Cylinder Head Torque and Valve Adjustment
..... 6-11
GENERAL DESCRIPTION
The engine tune up
is
important
to the
modern automo-
tive engine with
its
vastly improved power and perform-
ance.
The
higher compression ratios, improved electri-
cal systems
and
other advances
in
design, make today1 s
engines more sensitive
and
have
a
decided effect
on
power, performance and fuel consumption.
It
is
seldom advisable
to
attempt
a
tune up
by
correc-
tion
of one or two
items only. Time will normally
be
saved
and
more lasting results assured
if the
technician
will follow
a
definite
and
thorough procedure
of
analysis
and correction
of all
items affecting power, performance
and economy.
The tune
up
will
be
performed
in
two parts.
The
first
part will consist
of
visual and mechanical checks and
ad-
justments;
the
second part will consist
of
an instrument
checkout that
can be
performed with
any one of the
units
of service equipment available
for
this purpose. Always
follow
the
instructions provided
by the
manufacturer
of
the particular equipment
to be
used.
Additional checks
and
adjustments
are
included
in the
latter part
of
this section
for use as
required. Many
of
these operations
can be
used
to
isolate and correct trou-
ble located during
the
tune up. Where conditions
are
UB-
covered requiring major corrective action, refer
to the
appropriate section
of
this manual
or the
Passenger
Chassis Overhaul Manual
for
detailed service informa-
tion.
Typical illustrations
and
procedures
are
used except
where specific illustrations
or
procedures
are
necessary
to clarify
the
operation. Illustrations showing bench
op-
erations
are
used
for
clarification however
all
operations
can
be
performed
on the
vehicle.
MECHANICAL CHECKS
AND
ADJUSTMENTS
Spark Plug Removal
Remove any foreign matter from around spark plugs
by
blowing
out
with compressed
air,
then disconnect wires
and remove plugs.
Test Compression
(Fig. 1)
The compression check
is
important because
an
engine
with
low or
uneven compression cannot
be
tuned success-
fully.
It is
essential that improper compression
be cor-
rected before proceeding with
the
engine tune
up.
1.
Remove
air
cleaner
and
block throttle
and
choke
in
wide open position.
2.
Hook
up
starter remote control cable
and
insert
compression gauge firmly
in
spark plug port.
CAUTION: Whenever
the
engine
is
cranked
CHEVROLET
C*
IS SERVICE MANUAL

ENGINE 6-4
• Contact points with an overall gray color and only
slight roughness or pitting need not be replaced.
• Dirty points should be cleaned with a clean point
file.
Use only a few strokes of a clean, fine-cut con-
tact file. The file should not be used on other
metals and should not be allowed to become
greasy or dirty. Never use emery cloth or sand-
paper to clean contact points since particles will
embed and cause arcing and rapid burning of
points. Do not attempt to remove all roughness
nor dress the point surfaces down smooth.
Merely remove scale or dirt.
• Clean cam lobe with cleaning solvent, lubricate
cam lobe with "Delco Remy Cam and Ball Bearing
Lubricant" or its equivalent and rotate cam lubri-
cator wick 1/2 turn.
• Replace points that are burned or badly pitted.
NOTE: Where prematurely burned or badly
pitted points are encountered, the ignition sys-
tem and engine should be checked to determine
the cause of trouble so it can be eliminated.
Unless the condition causing point burning or
pitting is corrected, new points will provide no .
better service than the old points. Refer to
Section 6Y for an analysis of point burning or
pitting.
• Check point alignment (fig. 5) then, adjust distri-
. butor contact point gap to .019" (new points) or
.016"
(used points). Breaker arm rubbing block
must be on high point of lobe during adjustment.
NOTE: If contact points have been in service,
they should be cleaned with a point file before
adjusting with a feeler gauge.
• Check distributor point spring tension (contact
Fig. 8 - Manifold Heat Control Valve (In Line)
point pressure) with a spring gauge hooked to
breaker lever at the contact and pull exerted at 90
degrees to the breaker lever. The points should
be closed (cam follower between lobes) and the
reading taken just as the points separate. Spring
tension should be 19-23 ounces. If not within
limits,
replace.
Excessive point pressure" will cause excessive
wear on the points, cam and rubber block. Weak
point pressure permits bouncing or chattering,
resulting in arcing and burning of the points and
an ignition miss at high speed.
4.
Install rotor and distributor cap. Press all wires
firmly into cap towers.
Fig. 7 - Checking Fan Belt Tension
Fig. 9 - Manifold Heat Control Valve (V8)
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE
6-5
Service Battery and Battery Cables
1.
Measure the specific gravity of the electrolyte in
each cell (fig. 6). If it is below 1.230 (corrected to
80°F.) recharge with a slow rate charger, or if de-
sired, further check battery.
2.
Connect a voltmeter across the battery terminals and
measure the terminal voltage of the battery during
cranking (disconnect the coil primary lead at the
negative terminal during this check to prevent engine
from firing). If the terminal voltage is less than 9.0
volts at room temperature, approximately 80°
±
20°
F.,
the battery should be further checked. See
Section 6Y for further tests.
3.
Inspect for signs of corrosion on battery, cables and
surrounding area, loose or broken carriers, cracked
or bulged cases,- dirt and acid, electrolyte leakage
and low electrolyte level. !Fill cells to proper level
with distilled water or water passed through a
"demineralizer".
The top of the battery should be clean and the bat-
tery hold-down bolts properly tightened. Particular
care should be taken to see that the top of the battery
is kept clean of acid film and dirt. When cleaning
batteries, wash first with a dilute ammonia or soda
solution to neutralize any acid present and then flush
off with clean water. Keep vent plugs tight so that
the neutralizing solution does not enter the cell. The
hold-down bolts should be kept tight enough to prevent
the battery from shaking around in its holder, but
they should not be tightened to the point where the
battery case will be placed under a severe strain.
To insure good contact, the battery cables should
be tight on the battery posts. Oil battery terminal
felt washer. If the battery posts or cable terminals
are corroded, the cables should be cleaned separately
with a soda solution and wire brush. After cleaning
and before installing clamps, apply a thin coating of
petrolatum to the posts and cable clamps to help
retard corrosion.
If the battery has remained undercharged, check
for loose or defective fan belt, defective Delcotron,
high resistance in the charging circuit, oxidized
regulator contact points, or a low voltage setting.
If the battery has been using too much water, the
voltage output
is-
too high.
Service Deicotron and Regulator
The Delcotron and regulator tests during tune up con-
sist of the above battery tests; the condition of the battery
indicating further tests and adjustments as outlined in
Section 6Y.
Service Belts (Fig. 7)
Inspect belt condition.
Check and adjust if necessary for correct tension of
belt, as follows:
• Using a strand tension gauge, check the belt tension.
• Adjust belt until the specified tension is reached.
(See Tune Up Chart.)
Service Manifold Heat Valve (Figs. 8 or 9)
Check manifold heat control valve for freedom of oper-
ation. If shaft is sticking, free it up with GM Manifold
Heat Control Solvent or its equivalent.
NOTE: Tap shaft end to end to help free it up.
Tighten Manifold
Tighten intake manifold bolts to specifications in the
FLAME
ARRESTOR
FLAME
ARRESTOR
NON-VENTED\
CAP
V\ VALVE
CLOSED
POSITIVE (283 & 327)
POSITIVE
(IN LINE)
POSITIVE
(327)
POSITIVE
(396 & 427)
Fig.
10 -
Crank case
Ventilation Systems
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-6
CHOKE VALVE
COMPLETELY
CLOSED
PULL UPWARD ON
ROD TO END OF
TRAVEL
BEND ROD
TO ADJUST
ROD IN BOTTOM
OF SLOT
BOTTOM OF
ROD SHOULD
EVENWITH
TOP OF
HOLE
CHOKE VALVE
CLOSED
BOTTOM OF
ROD SHOULD
BE EVEN WITH
TOP OF HOLE
TOP OF ROD
SHOULD BE EVEN
WITH BOTTOM
OF HOLE (CHOKE
CLOSED)
^..BEND ROD TO
ADJUST
_PULL DOWNWARD
ON ROD TO CON-
TACT STOP
L6 (TYPICAL)
V8 327-275 HP
V8 350-295 HP
BEND ROI
TO ADJUST
PULL UPWARD ON
ROD TO CONTACT
STOP ON BRACKET
ALL V8 (EXCEPT 327-275 HP
AND 350-295 HP)
Fig.
11 - Remote Choke Adjustment
sequence outlined on Torque Sequence Chart. A slight
leak at the intake manifold destroys engine performance
and economy.
Service Fuel Lines and Fuel Filter
1.
Inspect fuel lines for kinks, bends or leaks and cor-
rect any defects found, • • •
2.
Inspect filter and replace if plugged.
NOTE:
If a complaint of poor high speed per-
formance exists on the vehicle, fuel pump tests
described in Section 6M should be performed.
Service Cooling System
1.
Inspect cooling system for leaks, weak hoses, loose
hose clamps and correct coolant level, and service
as required.
NOTE:
A cooling system pressure test, as de-
scribed in "Additional Checks and Adjustments"
in this section, may be performed to detect
internal or external leaks within the cooling
system.
Check and Adjust Accelerator Linkage
1.
Disconnect accelerator rod at carburetor throttle
lever.
2.
Hold carburetor throttle lever in wide position.
3.
Pull accelerator rod to wide open position. (On ve-
hicles equipped with automatic transmission, pull
through detent).
4.
Adjust accelerator rod to freely enter hole in carbu-
retor throttle lever.'
NOTE:
Accelerator linkage is outlined in de-
tail in Section 6M.
5. Connect accelerator rod at throttle lever.
Service Crankcase Ventilation (Fig. 10}
All engines have either "Positive" or "Closed Positive"
ventilation systems utilizing manifold vacuum to draw
fumes and contaminating vapors into the combustion
chamber where they are burned. Since it affects every
part of the engine, crankcase ventilation is an important
function and should be understood and serviced properly.
In both "Positive" and "Closed Positive" ventilation,
air is drawn through the engine, (through a regulating
valve) into the manifold, drawing' crankcase vapors and
fumes with it to be burned. "Positive" ventilation uses a
vented-meshed cap for clean air intake to the engine,
while . "Closed Positive" ventilation system draws the
clean air from the carburetor air cleaner and has a
nonvented oil filler cap.
1.
Ventilation valve may be checked as outlined under
"Additional Checks and Adjustments".
2.
Inspect for deteriorated or plugged hoses.
3.
Inspect all hose connections.
4.
On closed positive ventilation systems, remove flame
arrestor and wash in solvent then dry with com-
pressed air.
Service Air Injection Reactor System
Inspect air injection reactor system for evidence of
leaks,
deteriorated hoses, cracked air manifolds or tubes
and loose hose clamps. Inspect air injection pump belt
condition and tension. Make all necessary repairs as
outlined in "Section 6T".
Because of the relationship between "Engine Tune Up"
and "Unburned Exhaust Gases", the condition of Engine
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-14
b.
Bolt transmission to engine, then raise engine and
transmission assembly and install flywheel to
converter attaching bolts.
c. Install converter
housing*
underpan and starter.
3.
Tilt and lower engine and transmission assembly into
the chassis as a unit, guiding engine to align front
mounts with frame supports.
4.
Install front mount through bolts and torque to
specifications.
5.
Raise engine enough to install rear crossmember,
then install crossmember, install rear mount, lower
engine and torque bolts to specifications.
6. Remove lifting device and lifting adapter then install
rocker arm cover as outlined.
7.
On synchromesh equipped vehicles, install clutch
cross shaft engine bracket, then adjust and connect
clutch as outlined in Section 7.
8. Connect:
• Speedometer cable.
• Shift linkage at transmission.
9; Install propeller shaft.
10.
Remove jack stands and lower vehicle.
11.
Connect:
Power steering pump lines (if disconnected).
Vacuum line to power brake unit (if disconnected).
Fuel line at fuel pump.
Exhaust pipe at manifold flange.
Accelerator linkage at manifold bellcrank.
12.
Connect wires at:
Coil
Oil pressure switch
Temperature switch
Delcotron
Starter solenoid
13.
Install pulley, fan blade and fan belt as outlined in
Section 6K.
14.
Install radiator and shroud as outlined in Section 13.
15.
Install and adjust hood as outlined in Section 11.
16.
Connect battery cables.
17.
Fill with coolant, engine oil and transmission oil,
then start engine and check for leaks.
18.
Perform necessary adjustments and install air
cleaner.
MANIFOLD ASSEMBLY
Removal
1.
Remove air cleaner.
2.
Disconnect both throttle rods at bellcrank and re-
move throttle return spring.
3.
Disconnect fuel and vacuum lines at carburetor.
Disconnect choke cable on \A engines.
4.
Disconnect crankcase ventilation hose at rocker arm
cover.
5.
Disconnect exhaust pipe at manifold flange and dis-
card packing.
6. Remove manifold attaching bolts and clamps then
remove manifold assembly and discard gaskets.
7.
Check for cracks in manifold castings.
8. If necessary to replace either intake or exhaust
manifolds, separate them by removing one bolt and
two nuts at center of assembly. Reassemble mani-
folds using a new gasket. Tighten finger tight and
torque to specifications after assembly to cylinder
head. Transfer all necessary parts.
Installation
1.
Clean gasket surfaces on cylinder head and
manifolds*
2.
Position new gasket over manifold end studs on head
and carefully install the manifold in position making
sure the gaskets are in place.
3.
Install bolts and clamps while holding manifold in
place with hand.
4.
Torque bolts to specifications.
NOTE: On L6 engines center bolt and end bolt
torque differ.
5.
Connect exhaust pipe to manifold using a new
packing.
6. Connect crankcase ventilation hose at rocker arm
cover.
7.
Connect fuel and vacuum lines at carburetor.
8. On L4 engines connect choke cable and adjust as out-
lines in Section 6M.
9. Connect throttle rods at bellcrank and install throttle
return spring.
10.
Install air cleaner, start engine, check for leaks and
adjust carburetor idle speed and mixture.
ROCKER ARM COVER
Removal
1.
Disconnect crankcase ventilation hose(s) at rocker
arm cover.
2.
Remove air cleaner.
3.
Disconnect temperature wire from rocker arm cover
clips.
4.
Remove rocker arm cover. '
CAUTION: Do Not pry rocker arm cover loose
Gaskets adhering to cylinder head and rocker
arm cover may be sheared by bumping end of
rocker arm cover rearward with palm of hand or
a rubber mallet.
Installation
1.
Clean gasket surfaces on cylinder head and rocker
arm cover with degreaser then, using anew gasket,
install rocker arm cover and torque bolts to
specifications.
2.
Connect temperature wire at rocker arm cover clips.
3.
Install air cleaner.
4.
Connect crankcase ventilation hoses.
VALVE MECHANISM
Removal
1.
Remove rocker arm cover as outlined.
2.
Remove rocker arm nuts, rocker arm
balls,
rocker
arms and push rods.
NOTE:
Place rocker arms, rocker arm balls
and push rods in a rack so they may be rein-
stalled in the same location.
Installation and Adjustment
NOTE:
Whenever new rocker arms and/or
rocker arm balls are being installed, coat bear-
ing surfaces of rocker arms and rocker arm
balls with Molykote or its equivalent.
1.
Install push rods,
socket.
Be sure push rods seat in lifter
CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-19
OIL SEAL (REAR MAIN)
Replacement
The rear main bearing oil seal can be replaced (both
halves) without removal of the crankshaft.
NOTE:
Always replace the upper and lower
seal as a unit. Install with the lip facing toward
the front of the engine.
1.
With the oil pan removed, remove the rear main
bearing cap.
2.
Remove oil seal from the groove by lifting the end
tab (fig. 7L) then clean seal groove.
3.
Lubricate the lip and O.D. of a new seal with engine
oil. Keep oil off the parting line surface. Insert
seal in cap and roll it into place with finger and
thumb,
using light pressure so beads on seal O.D.
are not cut by seal groove at cap parting line. Be
sure tabs on seal are properly located in cross
grooves.
4.
To remove the upper half of the seal, use a small
hammer to tap a brass pin punch on one end of seal
until it protrudes far enough to be removed with
pliers (fig. 8L).
NOTE:
Always clean crankshaft surface re-
moving all foreign deposits before installing a
new seal. Also clean seal groove.
5. Lubricate the lip and O.D. of a new seal with engine
oil. Keep oil off the parting line surface. Gradually
push with a hammer handle, while turning crank-
shaft, until seal is rolled into place. (Similar to in-
stalling a main bearing.) Be careful that seal bead
on O.D. is not cut. Compress seal towards crank-
shaft as much as possible.
6. Install the rear main bearing cap (with new seal) and
torque to specifications. Be sure cross seal tabs
are in place and properly seated.
CRANKSHAFT PULLEY AND HUB
(Chevy II with L4 Engine)
Removal
1.
Drain radiator and disconnect upper and lower radi-
ator hoses at radiator.
2.
Remove radiator core as outlined in Section 13.
3.
Remove fan belt. Remove crankshaft pulley from
pulley hub.
4.
Install puller Tool J-6978 to pulley hub with two
3/8"
x 2" and one 5/16" x 2" bolts and remove hub
then remove puller tool.
Installation
1.
Coat oil seal contact area on hub with engine oil
position hub over crankshaft and key and start hub
into position with a mallet. Using Tool J-5590 drive
onto crankshaft until it bottoms against crankshaft
gear.
NOTE:
Crankshaft extends slightly through hub
and a tool is necessary to drive hub completely
into bottomed position.
2.
Install pulley onto hub.
NOTE:
There are two 3/8" holes and one
5/16" hole that must be matched on hub in order
Fig.
9L - Removing Torsional Damper
to properly position timing mark.
3.
Install fan belt and adjust using strand tension gauge.
4.
Install radiator as outlined in Section 13.
TORSIONAL DAMPER
Removal
1.
Remove radiator core, as outlined in Section 13.
2.
Remove fan belt and (if so equipped) accessory drive
pulley and belt.
3.
Install Tool J-6978 to damper and turn puller screw
to remove damper (fig. 9L). Remove tool.
Installation
1.
Coat front cover oil seal contact area of damper with
engine oil.
CAUTION: It is necessary to use installer
Tool J-22197 to prevent the inertia weight sec-
Fig.
10L - Installing Torsional Damper
CHEVROLET CHASSIS SERVICE MANUAL