1967 CHEVROLET CAMARO spark plugs

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 6-2

remotely at the starter, with a special jumper

cable or other means, the primary distributor

lead must be disconnected from the negative

post on the coil and the ignition switch must be

in the "ON" position. Failure to do this will

result in a damaged grounding circuit in the

ignition switch.

3.
Crank engine through at least four compression

strokes to obtain highest possible reading.

4.
Check and record compression of each cylinder.

5.
If one or more cylinders read low tor uneven, inject

about a tablespoon of engine oil on top of pistons

in low reading cylinders (through spark plug

port).
Crank engine several times and recheck

compression.

• If compression comes up but does not necessarily

reach normal, rings are worn.

• If compression does not improve, valves are

burnt, sticking or not seating properly.

• If two adjacent cylinders indicate low compres-

sion and injecting oil does not increase compres-

sion, the cause may be a head gasket leak between

the cylinders. Engine coolant and/or oil in cylin-

ders could result from this defect.

NOTE: If a weak cylinder cannot be located

with the compression check, see "Cylinder Bal-

ance Test" under "Additional Checks and Adjust-

ments" in this section.

Service and Install Spark Plugs (Fig. 2)

1.
Inspect each plug individually for badly worn elec-

trodes,
glazed, broken or blistered porcelains and

replace plugs where necessary. Refer to spark plug

diagnosis information presented in Section 6Y for an

analysis of plug conditions.

2.
Clean serviceable spark plugs thoroughly, using an

abrasive-type cleaner such as sand blast. File the

center electrode flat.

3.
Inspect each spark plug for make and heat range. All

plugs must be of the same make and number.

4.
Adjust spark plug gaps to specifications using a

round feeler gauge.
PORCELAIN

INSULATOR

INSULATOR CRACKS

OFTEN OCCUR HERE

CENTER ELECTRODE

[FILE FLAT WHEN

ADJUSTING GAP-

[DO NOT BEND!
(PROPER GAP)

(BEND TO ADJUST GAP)

CAUTION:

adjust gap.
Fig.
2 - Spark Plug Detail

Never bend the center electrode to

Always adjust by bending ground or

side electrode.

If available, test plugs with a spark plug tester.

Inspect spark plug hole threads and clean before in-

stalling plugs. Corrosion deposits can be removed

with a 14 mm. x 1.25 SAE spark plug tap (available

through local jobbers) or by using a small wire brush

in an electric drill. (Use grease on tap to catch

chips.)

ADJUST DWELL

ANGLE SETTING OR

POINT OPENING

Fig.
1 - Checking Compression
Fig.
3 - Distributor (In Line)

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE
6-3

(ROUND) Y~~fll^H

CENTRIFUGAL
A ^k

ADVANCE--jflgKpl

MECHANISM
UB|

CAM
KSK^2

LUBRICATOR
VlSMi

REPLACEMENT
^BK

-^ADJUST
SQUARELY

AND
JUST

TOUCHING
LOBE

OF
CAM
/ROTOR

HBB
__

I^BH^F
?
(SOUARE)

^K^ I /—
CAM

jKft^J / LUBRICATOR

H^T^
CAUTION!

QV NEVER
OIL

•L-^
CAM LUBRICATOR-

REPLACE
WICK

WHEN
NECESSARY
LATERAL

MISALIGNMENT
PROPER

LATERAL ALIGNMENT

Fig.
4- Distributor (V8)

CAUTION: Use extreme care
-when
using tap to

prevent cross threading. Also crank engine sev-

eral times to blow out any material dislodged

during cleaning operation.

7. Install spark plugs with new gaskets and torque to

specifications.

NOTE:
The following are some of the

greatest causes of unsatisfactory spark plug

performance.

•
Installation of plugs with insufficient torque to

fully seat the gasket.

•
Installation of the plugs using excessive torque

which changes gap settings.

•
Installation of plugs on dirty gasket seal.

•
Installation of plugs into corroded spark plug hole

threads.

8^ Connect spark plug wiring.

Service
Ignition System

1.
Remove distributor cap, clean cap and inspect for

cracks, carbon tracks and burned or corroded ter-

minals. Replace cap where necessary.

2.
Clean rotor and inspect for damage or deterioration.

Replace rotor where necessary.

3.
Replace brittle, oil soaked or damaged spark plug

wires.
Install all wires to proper spark plug. Proper

positioning of spark plug wires in supports is impor-

tant to prevent cross-firing.

4.
Tighten all ignition system connections.

5. Replace or repair any wires that are frayed, loose or

damaged.
Us
CORRECT
LATERAL MISALIGNMENT BY

j BENDING
FIXED CONTACT SUPPORT

[NEVER
BEND BREAKER LEVER

Fig.
5 - Point Alignment

Magnetic
Pulse(Breakerless)
Distributor

There are no moving parts in the ignition pulse ampli-

fier, and the distributor shaft and bushings have perma-

nent type lubrication, therefore no periodic maintenance

is required for the magnetic pulse ignition system. Refer

to Section 6Y for an analysis of problems and/or repair

procedures encountered on the Transistorized (Magnetic

Pulse) ignition system.

Standard
(Breaker Point) Distributor
(Figs.
3 or 4)

1.
Check the distributor centrifugal advance mechanism

by turning the distributor rotor in a clockwise direc-

tion as far as possible, then releasing the rotor to

see if the springs return it to its retarded position.

If the rotor does not return readily, the distributor

must be disassembled and the cause of the trouble

corrected.

2.
Check to see that the vacuum spark control operates

freely by turning the movable breaker plate counter-

clockwise to see if the spring returns to its retarded

position. Any stiffness in the operation of the spark

control will affect the ignition timing. Correct any

interference or binding condition noted.

3.
Examine distributor points and clean or replace if

riecessary.

DO
NOT SUCK

IN
TOO MUCH

ELECTROLYTE

TAKE
READING

AT
EYE LEVEL

Fig.
6 - Testing Specific Gravity of Battery

CHEVROtET
CHASSIS SERVICE MANUAL

ENGINE
6-8

Check
and
Adjust Ignition Timing
(Fig. 13)

1.
Disconnect
the
distributor spark advance hose
and

plug
the
vacuum source opening.

2.
Start engine
and run at
idle speed
(see
tune
up
chart).

3.
Aim
timing light
at
timing
tab.

NOTE:
- The
markings
on the
tabs
are in 2°

increments
(the
greatest number
of
markings
on

the
"A"
side
of the "O"). the "O"
markings
is

TDC
of
#1 cylinder
and all
BTDC settings fall
on

the
"A"
(advance) side
of "O".

4.
Adjust
the
timing
by
loosening
the
distributor clamp

and
,
rotating
the
distributor body
as
required, then

tighten
the
clamp.

5.
Stop engine
and
remove timing light
and
reconnect

the spark advance hose.

Adjust Idle Speed
and
Mixture
(Fig. 14)
(Except when

equipped with
Air
Injection Reactor System)

1.
As a
preliminary adjustment, turn idle mixture

screws lightly
to
seat
and
back
out 2
turns.

CAUTION:
Do not
turn idle mixture screw

tightly against seat
or
damage
may
result.

2.
With engine running
at
operating temperature (choke

wide open) adjust idle speed screw
to
bring idle

speed
to
specified
rpm
(automatic transmission
in
drive, manual transmission
in
neutral).

3.
Adjust idle mixture screw
to
obtain highest steady

idle speed
(1/4
turn
out
from lean roll).

4.
Repeat Steps
2 and 3 as
needed
for
final adjustment.

5.
Shut down
the
engine, remove gauges
and
install
air

cleaner.

Adjust Idle Speed
and
Mixture
(Fig. 14)
(With
Air

Injection Reactor System)

The recommended adjustment procedure
for Air
Injec-

tion Reactor System equipped engines
is as
follows:

1.
As a
preliminary adjustment, turn idle mixture

screws lightly
to
seat
and
than back
out 3
turns.

CAUTION:
Do not
turn idle mixture screw

tightly against seat
or
damage
may
result.

2.
With engine running
at
operating temperature, choke

wide open,
and
parking brake applied, adjust idle

specified idle speed (automatic

"drive"-manual transmission
in
to

in
screw

transmission

"neutral").

;3.
Adjust idle mixture screw (turn
in) to
"lean roll"

position; then turn screw
out 1/4
turn
(1/4
turn rich

from "lean roll").
The
definition
of
"lean roll" point

is
a 20 to 30 rpm
drop
in
engine speed, obtained
by

leaning
the
idle mixture.

4.
Repeat Steps
2 and 3 as
needed
for
final adjustments.

ADDITIONAL CHECKS
AND
ADJUSTMENTS

Testing Crankcase Ventilation Valve
(Fig. 15) 0

1.
Connect tachometer
and
vacuum gauge
as for
idle

speed
and
mixture adjustment.

2.
Set
parking brake, start engine
and
adjust idle speed

and mixture.

3.
Disconnect ventilation hose
at
valve, block opening
of

valve
and
read engine
rpm
change.

4.
A
change
of
less than
50 rpm
indicates
a
plugged

ventilation valve
-
replace
the
valve.

Cylinder Balance Test
(Fig. 16)

It
is
often difficult
to
locate
a
weak cylinder.
A com-

pression test,
for
example, will
not
locate
a
leaky intake

manifold,
a
valve
not
opening properly
due to a
worn

camshaft,
or a
defective spark plug.

With
the
cylinder balance test,
the
power output
of one

cylinder
may be
checked against another, using
a set of

grounding leads. When
the
power output
of
each cylinder

is
not
equal,
the
engine will lose power
and run
roughly.

Perform
a
cylinder balance test
as
follows:

1.
Connect
the
tachometer
and
vacuum gauge.

2.
Start engine
and run at 1500 rpm.

3.
Ground large clip
of
grounding leads
and
connect
in-

dividual leads
to all
spark plugs except
the
pair being

tested.

Divide
the
firing order
in
half
and
arrange
one
half

over
the
other.
The
cylinders
to be
tested together
ap-

pear
one
over
the
other.

L4 Firing Order
V8 Firing Order

1-8-4-3-6-5-7-2

1-6, 8-5, 4-7, 3-2

1-3-4-2
= 1-3

4-2

L6 Firing Order

1-5-3-6-2-4
=
=
1-4. 3-2

1-5-3

6-2-4
1-6, 5-2, 3-4
1-8-4-3

6-5-7-2

4.
Operate engine
on
each pair
of
cylinders
in
turn
and

note engine
rpm and
manifold vacuum
for
each pair.

A variation
of
more than
1
inch
of
vacuum
or 40 rpm

between pairs
of
cylinders being tested indicates that

the cylinders
are off
balance.

Battery

The battery should
be
checked with special testing

equipment
and to the
equipment manufacturers specifica-

tions.
See
Section 6Y
for
complete information
on
battery

tests.

Ignition

The following additional ignition checks
may be
made

with
any of
several pieces
of
equipment available
for un-

covering
the
source
of
engine difficulties.
The
specific

operating instructions
of the
equipment manufacturer

should
be
followed:

Cranking voltage

Ignition switch

Distributor resistance

Secondary resistance

Ignition output
and
secondary leakage

Cranking Voltage
(Fig. 17)

1.
Disconnect coil primary lead
at the
coil negative

terminal
to
prevent engine from firing during

cranking.

2.
Connect voltmeter between primary terminal
of coi|

(resistance wire side)
and
ground.

3.
Operate starting motor.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-10

Fig.
15 - Crank case Ventilation Valve

a. If voltage is 9 volts or more and cranking speed

is satisfactory, the battery, starter, cables,

starter switch and ignition circuit to coil (by-

passing resistance wire) are in good condition.

b.
If below 9 volts, check circuit until difficulty is

located.

Meter reading below specification—Weak bat-

tery; defective cables, connections, switch or

starter; defective ignition circuit to coil.

Cranking speed below normal--Excessive re-

sistance in cables or starting motor; excessive

mechanical drag in engine.

Uneven cranking speed—Uneven compression,

defective starter or starter drive.

Ignition Switch

With voltmeter connected as described for the Cranking

Voltage Test, turn ignition switch to ON. Voltage should

drop to 5 to 7 volts as current is now passing through

high resistance wire connected between ignition switch

and (+) positive terminal of coil. If battery voltage of

12 volts is obtained, the starter solenoid is by-passing

the high resistance wire connected between ignition

switch and (+) positive terminal of coil, thus the starter

solenoid is not functioning properly to bypass the ignition

resistance wire or the ignition circuit is incorrectly

wired.

Distributor Resistance

Use equipment as directed by manufacturer.

Excessive
(t n ti ft

Fig.
16 - Cylinder Balance Test
Fig.
17 - Testing Cranking Voltage

resistance in primary circuit must be eliminated before

continuing with test procedure.

Secondary Resistance

Use equipment as dire6ted by manufacturer.

• Uniform "normal readings" as specified by manu-

facturer indicate all secondary circuit components

are in good condition.

• If all readings are "below normal," check for cor-

roded coil tower terminal, poorly connected or

broken coil wire, center cap electrode or rotor tip

burned, or an open secondary in coil.

• If readings are "higher than normal" at two or more

plugs adjacent in firing order, cross firing is oc-

curring in distributor cap or between spark plug ca-

bles concerned.

• If meter reads off scale to left, the coil polarity is

reversed. Check for reversed coil primary wires,

wrong coil or reversed vehicle battery connections.

Ignition Output and Secondary Leakage

Use equipment as directed by manufacturer.

• GOOD readings indicate both ignition output and

secondary insulation are good.

• If all readings are BAD or if ignition test calibrator

cannot be adjusted to Set Line, check for high re-

sistance in primary circuit, defective distributor

points, coil or condenser.

e If readings are BAD when certain plug wires are

lifted off, check for cracks or carbon tracks in dis-

tributor cap or defective insulation on those plug

wires being lifted off.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-15

2.
Install rocker arms, rocker arm balls and rocker

arm
nuts.
\
Tighten rocker arm nuts until all lash is

eliminated. .

3.
Adjust valves when lifter is on base circle of cam-

shaft lobe as follows:

a. Mark distributor housing, with chalk, at each cyl-

inder position (plug wire) then disconnect plug

wires at spark plugs and coil and remove distri-

butor cap and plug wire assembly (if not previ-

ously done).

b.
Crank engine until distributor rotor points to

number one cylinder position and breaker points

are open. Both valves on number one cylinder

may now be adjusted.

c. Back out adjusting nut until lash is felt at the push

rod then turn in adjusting nut until all lash is re-

moved. This can be determined by checking push

rod side play while turning adjusting nut (fig. 2L).

When play has been removed, turn adjusting nut

in one full additional turn (to center lifter

plunger).

d. Adjust the remaining valves, one cylinder at a

time,
in the same manner.

4.
Install distributor cap and spark plug wire assembly.

5.
Install rocker arm cover as outlined.

6. Adjust carburetor idle speed and mixture.

VALVE LIFTERS

Hydraulic valve lifters very seldom require attention.

The lifters are extremely simple in design readjustments

are not necessary, and servicing of the lifters requires

only that care and cleanliness be exercised in the han-

dling of parts.

Locating Noisy Lifters

Locate a noisy valve lifter by using a piece of garden

Fig.
2L - Valve Adjustment
hose approximately four feet in length. Place one end of

the hose near the end of each intake and exhaust valve

with the other end of the hose to the ear. In this manner,

the sound is localized making it easy to determine which

lifter is at fault.

Another method is to place a finger on the face of the

valve spring retainer. If the lifter is not functioning

properly, a distinct shock will be felt when the valve

returns to its seat.

The general types of valve lifter noise are as follows:

1.
Hard Rapping Noise--Usually caused by the plunger

becoming tight in the bore of the lifter body to such

an extent that the return spring can no longer push

the plunger back up to working position. Probable

causes are:

a. Excessive varnish or carbon deposit causing

abnormal stickiness.

b.
Galling or "pickup" between plunger and bore of

lifter body, usually caused by an abrasive piece

of dirt or metal wedging between plunger and

lifter body.

2.
Moderate Rapping Noise--Probable causes are:

a. Excessively high leakdown rate.

b.
Leaky check valve seat.

c. Improper adjustment.

3.
General Noise Throughout the Valve Train—This

will, in almost all cases, be a definite indication of

insufficient oil supply, or improper adjustment.

4.
Intermittent Clicking—Probable causes are:

a. A microscopic piece of dirt momentarily caught

between ball seat and check valve ball.

b.
In rare cases, the ball itself may be
out-of-

round or have a flat spot.

c. Improper adjustment.

In most cases where noise exists in one or more lifters

all lifter units should be removed, disasssmbled, cleaned

in a solvent, reassembled, and reinstalled in the engine.

If dirt, varnish, carbon, etc. is shown to exist in one unit,

it more than likely exists in all the units, thus it would

only be, a matter of time before all lifters caused trouble.

Removal

1.
Remove valve mechanism as outlined.

2.
Mark distributor housing, with chlak, at each cylin-

der position (plug wire) then disconnect plug wires at

spark plugs and coil and remove distributor cap and

plug wire assembly.

3.
Crank engine until distributor rotor points to number

one position, then disconnect distributor primary lead

at coil and remove distributor.

4.
Remove push rod covers (discard gaskets).

5.
Remove valve lifters.

NOTE: Place valve lifters in a rack so they

may be reinstalled in the same location.

Installation

1.
Install valve lifters.

NOTE:
Whenever new valve lifters are being

installed, coat foot of valve lifters with Molykote

or its equivalent.

2.
Install push rod covers, using new gaskets, and

torque bolts to specifications.

3.
Install distributor, positioning rotor to number one

cylinder position, then connect primary lead at coil.

4.
Install and adjust valve mechanism as outlined.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-26

6. Remove lifting device and lifting adapter then install

rocker arm covers 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.

• Transmission cooler lines (if so equipped).

9. Install propeller shaft.

10.
Remove jack stands and lower vehicle.

11.
Connect: \ '

Power steering pump lines (if so equipped).

Vacuum line to power brake unit (if so equipped).

Exhaust pipes at manifold flanges.

Accelerator linkage at pedal lever.

Fuel line at fuel pump.

Engine cooler lines (if so equipped).

Oil pressure gauge lines (if so equipped).

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.

INTAKE MANIFOLD

Removal

1.
Drain radiator and remove air cleaner.

2.
Disconnect:

Battery cables at battery.

Upper radiator and heater hose at manifold.

Accelerator linkage at pedal lever.

Fuel line at carburetor. ;

Wires at temperature sending switch and coil

(both sides).

Power brake hose at carburetor base.

Spark advance hose at distributor.

Crankcase ventilation hoses (as required).

3.
Remove distributor cap and mark rotor position with

chalk. Remove distributor clamp and distributor,

then position distributor cap rearward clear of

manifold.

4.
Remove coil.

5.
Remove manifold-to-head attaching bolts, then re^

move manifold, (with carburetor on) from engine and

discard gaskets and seals.

6. If manifold is to be replaced,,transfer:

Carburetor and carburetor mounting studs.

Temperature sending switch.

Water outlet and thermostat (use new gasket).

Heater hose adapter.

Choke coil.

Installation

1.
Clean gasket and seal surfaces of manifold, cylinder
heads and block.

2.
Install manifold end seals on block as shown (fig.

2V).

3.
Install side gaskets on cylinder heads using sealing

compound around water passages (fig. 2V).

4.
Install manifold bolts, and torque to specifications in

the sequence outlined on the Torque Sequence Chart.

5.
Install coil.

6. Install distributor with the rotor pointing at the chalk

mark, then install distributor cap.

NOTE:
If the crankshaft has been rotated while

the distributor was removed, time distributor to

number 1 cylinder as outlined in Section 6Y.

7.
Connect:

Battery cables at battery.

Upper radiator and heater hose at manifold.

Accelerator linkage at pedal lever.

Fuel line at carburetor.

Wires at temperature sending switch and coil

(both sides)!

Power brake hose at carburetor base.

Spark advance hose at distributor.

Crankcase ventilation hoses (as required).

Fill with coolant, start engine, check for leaks and

adjust timing and carburetor idle speed and mixture.

EXHAUST MANIFOLD

Removal

NOTE:
If equipped with "Air Injection Reactor

System", remove air manifold and tubes as out-

lined in Section 6T.

1.
Disconnect battery ground cable.
-

2.
Disconnect and remove Delcotron (as required).

3.
On 396 and 427 cu. in. engines, remove spark plugs

Fig. 2V - Intake Manifold Gasket and Seal Location

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-27

and spark plug shields.

4.
Remove exhaust manifold flange nuts, then lower ex-

haust pipe assembly (hang exhaust pipe from frame

with wire).

5.
Bend french lock tabs (fig. 3V), remove end bolts

then remove center bolts and remove manifold from

engine.

NOTE: A 9/16 thin-wall 6 point socket, sharp-

ened at the leading edge, then started on the head

of the bolt and tapped in place with a hammer,

simplifies bending of french locks.

Installation

1.
Clean mating surfaces on manifold and head, then

install manifold in position and install center bolts.

2.
Install end bolts with french locks under them.

3.
Torque center bolts to specifications, then torque end

bolts to specifications, and bend french lock tabs to

lock end bolts.

4.
Using a new flange gasket install exhaust pipe to

manifold flange.

5.
On 396 and 427 cu. in. engines, clean and install

spark plugs using new gaskets. (Torque spark plugs

to specifications.)

6. Install and connect Delcotron.

7.
Connect the battery ground cable.

8. Start engine and check for leaks.

ROCKER ARM COVER

Removal

1.
Remove air cleaner.

2.
Disconnect crankcase ventilation hoses (as required).

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
Installation

1.
.Clean gasket surfaces on cylinder head and rocker

arm cover with degreaser then, using a new gasket,

install rocker arm cover and torque bolts to

specifications. .

2.
Connect crankcase ventilation hoses (if disconnected).

3.
Connect temperature wire at rocker arm cover clips.

4.
Install air cleaner.

VALVE MECHANISM

Removal

1.
Remove rocker arm covers 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; Be sure push rods seat in lifter

socket.

2.
Install rocker arms, rocker arm balls and rocker

arm nuts.

3.
Adjust valves when lifter is on base circle of cam-

shaft lobe as follows:

With Hydraulic Valve
Lifters

2L.
Crank engine until
mark on torsional damper

lines up with center or "0M mark on the timing

tab and the engine is in the number 1 firing posi-

tion. This may be determined by placing fingers

on the number 1 cylinder valve as the mark on the

rocker arm cover may be sheared by bumpii

end of rocker arm cover rearward with palm

hand or a rubber mallet.

Fig.
3V - Exhaust Manifold French Locks
Fig.
4V - Valve Adjustment (Hydraulic)

CHEVROLET CHASSIS SERVICE MANUAL