1967 CHEVROLET CAMARO check engine light

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 6-29

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 ab-

normal stickiness.

b.
(Sailing or "pick-up" 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-rThis

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, disassembled, cleaned

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

If dirt, corrosion, 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 intake manifold as outlined.

2.
Remove valve mechanism as outlined.

3.
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 intake manifold as outlined.

3.
Install and adjust valve mechanism as outlined.

VALVE STEM OIL SEAL AND/OR VALVE SPRING

Replacement

1.
Remove rocker arm cover(s) as outlined.

2.
Remove spark plug, rocker arm and push rod on the

cylinders to be serviced.

3.
Apply compressed air to the spark plug hole to hold

tl*e valves in place.

NOTE: A tool to apply air to the cylinder is

available through local jobbers or may be manu-

factured. In manufacturing this Tool a AC-46N

Spark Plug or its equivalent is recommended.

This will make the Tool universal for all

Chevrolet engines. Chisel the spark plug as

shown, then drive the porcelain out of the plug

by tapping the center electrode against a hard

block. Using a 3/8" pipe tap, cut threads in the

remaining portion of the spark plug and assem-

ble as shown (fig. 6V).
Fig.
6V - Air Adapter Tool

4.
Using Tool J-5892, to compress the valve spring, re-

move the valve locks, valve cap, and valve spring and

damper (fig. 7V).

5.
Remove valve stem oil seal.

6. Remove as follows:

283, 327 and 350 eu. in.
Engines

a. To replace, set the valve spring and damper,

valve shield and valve cap in place. The close

coiled end of the spring is installed against the

cylinder head.

b.
Compress the spring with Tool J-5892 and install

oil seal in the lower groove of the stem, making

sure the seal is flat and not twisted.

NOTE: A light coat of oil on the seal will help

prevent twisting.

Fig.
7V - Compressing Valve Spring

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-37

Fig.
27V—Removing Camshaft

4.
Set dial indicator on zero, then rotate the damper

slowly, or attach an auxiliary starter switch and

"bump" the engine over, until the push rod is in the

fully raised position.

CAUTION: 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 dam-

aged grounding circuit in the ignition switch.

5.
Compare the total lift recorded from the dial indica-

tor with specifications.

6. Continue to rotate the crankshaft until the indicator

reads zero. This will be a check on the accuracy of

the original indicator reading.

7.
If camshaft readings for all lobes are within specifi-

cations, remove dial indicator assembly.

8. Install and adjust valve mechanism as outlined.

Removal

1.
Remove valve lifters as outlined.

2.
Remove crankshaft front cover as outlined.

3.
Remove grille as outlined in Section 13.

4.
Remove fuel pump push rod as outlined * in Sec-

tion 6M.

5.
Complete camshaft removal as follows:

CAUTION: All camshaft journals are the same

diameter and care must be used in removing

camshaft to avoid damage to bearings.

Remove camshaft sprocket to camshaft bolts then

remove sprocket and timing chain together. Sprocket

is a light fit on camshaft. If sprocket does not come

off easily a light blow on the lower edge of the

sprocket (with a plastic mallet) should dislodge the

sprocket.

Install two 5/16" - 18 x 4" bolts in camshaft bolt

holes then remove camshaft (fig. 27V).

Installation

NOTE: Whenever a new camshaft is installed
CONVERTER

BOLT AREA -

DEPRESSED

SYNCHROMESH
RING

GEAR

TRANS.,

AUTOMATIC

Fig.
28V - Flywheel Installation (Typical)

coat camshaft lobes with Molykote or its

equivalent.

1.
Lubricate camshaft journals with engine oil and in-

stall camshaft.

2.
Install timing chain on camshaft sprocket. Hold the

sprocket vertical with the chain hanging down, and

orient to align marks on camshaft and crankshaft

sprockets. Refer to Figure 20V.

3.
Align dowel in camshaft with dowel in hole in cam-

shaft sprocket then install sprocket on camshaft.

Refer to Figure 25V.

4.
Draw the camshaft sprocket onto camshaft using the

mounting bolts. Torque to specifications.

5.
Lubricate timing chain with engine oil.

6. Install fuel pump push rod as outlined in Section 6M.

7.
Install grille as outlined in Section 13.

8. Install crankcase front cover as outlined.

9. Install valve lifters as outlined.

FLYWHEEL

Removal

With transmission and/or clutch housing and clutch

removed from engine, remove the flywheel.

Installation

1.
Clean the mating surfaces of flywheel and crankshaft

to make certain there are no burrs.

2.
Install flywheel on crankshaft and position to align

dowel hole of crankshaft flange and flywheel (fig.

28V).

NOTE: On Automatic Transmission equipped

engines, the flywheel must be installed with the

flange collar to transmission side (fig. 33V).

ENGINE MOUNTS

Engine mounts (fig. 34V) are the nonr adjustable type

and seldom require service. Broken or deteriorated

mounts should be replaced immediately, because of the

added strain placed on other mounts and drive line

components.

Front Mount Replacement

1.
Remove nut, washer and engine mount through-bolt.

2.
Raise engine to release weight from mount.

3.
Remove mount from engine.

CHEVROLET CHASSIS SERVICE MANUAL

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-3

Idle Speed and Mixture Adjustment (With Air Injection

Reactor System)

The following is the recommended procedure for Air

Injection Reactor System equipped engines.

NOTE: This adjustment should be performed

with engine at operating temperature and parking

brake applied.

1.
Remove air cleaner.

2.
Connect tachometer 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 3 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 dirve, synchronized transmission in

neutral).

5.
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.

NOTE: On air conditioned vehicles, turn air

conditioning "OFF" on in-line, 283, 327, and'

350 cu. in. engines, and turned "ON" and hot

idle compensator held closed on 396 and 427 cu.

in. engines.

6. Repeat Steps 4 and 5 as needed for final adjustment.

NOTE: If necessary, final adjustment of the
carburetor may be made with air cleaner

installed.

7.
Shut down the engine, remove gauges and install air

cleaner. *

Fast Idle Adjustment

Rochester
4MV and Holley

With fast idle lever on high step of cam and choke valve

open (engine warm) set fast idle to give specified engine

rpm. Adjust sejrew on Rochester 4MV and bend fast

idle lever *pn Holley. .

Choke Adjustment

With Remote Choke (Fig. 2c)

1.
Remove air cleaner and check to see that choke

valve and rod move freely.

2.
Disconnect choke rod at choke lever.

3.
Check choke adjustment as follows:

On all except 275 and 300 h.p. 327 cu. in. engines,

hold choke valve closed and pull.rod up against stop.

The top of choke rod end should be 1/2-1 rod diame-

ter above top of hole in choke valve lever.

On 275 and 300 h.p. 327 cu. in. engines, hold choke

valve closed and push rod down against stop on ther-

mostat bracket. The top of the choke rod should be

1/2-1 rod diameter below the top of the hole in the

choke lever.

4.
If necessary, adjust rod length by bending rod at

offset bend. (Bend must be such that rod enters

choke lever hole freely and squarely).

5.
Connect rod at choke lever and install air cleaner.

With Manual Choke (Carter YF)

1.
Remove air cleaner.

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

BE EVEN WITH

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 ROD

TO ADJUST

PULL UPWARD ON

ROD TO CONTACT

STOP ON BRACKET

ALL V8 (EXCEPT 327-275 HP

AND 350-295 HP)

Fig.
2C—Remote Choke Adjustment

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE FUEL 6M-4

Fig.
3C-Fuel Level Sight Plug

2.
Push hand choke knob in to within 1/8" of instru-

ment panel.

3.
Loosen choke cable clamp at carburetor bracket and

adjust cable through the clip until the choke valve

is wide open.

4.
Tighten cable clamp at carburetor bracket and check

operation of choke valve to ensure full closed and

wide open positions.

5. Install air cleaner.

Float Adjustment

Ho/fey (Model 4150
Center
Inlet & Model 2300)

1.
Remove air cleaner then remove the fuel level sight

plugs (Fig. 3c)

2.
With parking brake on, and transmission in neutral,

start the engine and allow it to idle.

3.
With the car on a level surface, the fuel level should

be on a level with the threads at the bottom of the

sight plug port (plus or minus 1/32 inch).

NOTE:
No float drop adjustment is required

on this carburetor.

4.
If necessary to adjust (either or both bowls), loosen

inlet needle lock screw and turn the adjusting nut

clockwise to lower or counter-clockwise to raise

fuel level, then tighten lock screw.

NOTE:
1/6 turn of adjusting nut equals ap-

proximately 1/16" fuel level change.

5. Allow a minute for fuel level to stabilize then re-

check the level at sight plug.

6. Readjust, if necessary, until proper level is obtained,

then install sight plug and air cleaner.

NOTE:
To assure proper secondary float level

setting it is advisable to accelerate primary

throttles slightly and hand operate secondary
throttle. This assures a stabilized secondary

fuel level.

Additional Adjustments

The following adjustments may be made without re-

moving the carburetor from the engine. For procedure

refer to Section 6M of the Overhaul Manual under the

carburetor being serviced.

Rochester BV

• Float

• Idle Vent

• Choke Rod (Fast Idle)

• Choke Vacuum Break

• Choke Unloader

Rochester 2GV

• Float

• Accelerator Pump

• Idle Vent

• Choke Rod (Fast Idle)

• Choke Vacuum Break

• Choke Unloader

• Secondary Throttle Opening

• Secondary Throttle Lockout

Rochester 4MV

• Float

• Accelerator Pumj)

• Idle Vent

• Air Valve

• Choke Rod

• Choke Vacuum Break

• Choke Unloader

• Air Valve Lockout

• Secondary Opening

• Secondary Lockout

Carter YF

• Float

• Idle Vent

• Choke Rod (Fast Idle)

• Choke Vacuum Break

• Choke Unloader

Holley 4160 and 4150
(Except End
Inlet)

• Float

• Air Vent Valve

• Accelerator Pump

• Choke Vacuum Break

• Choke Unloader

Holley 2300 and 4150
(End
Inlet)

• Air Vent Valve (except 2300)

• Accelerator Pump

• Choke Vacuum Break

• Choke Unloader

Removal

Flooding, stumble on acceleration and other perform-

mance complaints are, in many instances, caused by the

presence of dirt, water, or other foreign matter in the

carburetor. To aid in diagnosing the cause of the com-

plaint, the carburetor should be carefully removed from

the engine without draining the fuel from the bowl.

The contents of the fuel bowl may then be examined for

contamination as the carburetor is disassembled.

1.
Remove air cleaner and gasket.

2.
Disconnect fuel and vacuum lines from carburetor.

CHEVROLET CHASSIS SERVICE 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

ENGINE FUEL 6M-9

4.
Wash body with cleaning solvent and wip dry.

5. Wash filter element by sloshing up and down in

cleaning solvent.

6. Dry filter unit with an air hose or let stand until

dry.

7. Fill body of cleaner to full mark with SAE 50 engine

oil. If expected temperatures are to be consistently

below freezing, use SAE 20 engine oil.

8. Assemble filter and cover assembly to body of

cleaner.

9. Install cleaner, making sure it fits tight and is set

down securely. \

OIL
WETTED
PAPER
ELEMENT

Replacement

1.
Remove wing nut, washer and cover.

2.
Remove paper element and discard.

3.
Remove bottom section of air cleaner and gasket

on air horn of carburetor. Discard air horn gasket.

4.
Clean bottom section of air cleaner and cover pieces

thoroughly, to remove dust and grime.

NOTE:
Check bottom section of air cleaner

seal for tears or cracks.

5. Install a new gasket on carburetor air horn and set

bottom section of air cleaner on carburetor.

6. Install new paper element on bottom section of air

cleaner with either end up.

NOTE:
Plastisol seal is the same material on

both ends.

7. Install cover, washer and wing nut.

Testing (Fig. 5A)

Tool J-7825, is designed to check paper element air

cleaners to determine whether the element has ma-

terially decreased in efficiency arid should be replaced

or has only slightly increased air restriction and is

suitable for further service. In combination with a

tachometer, this instrument will quickly and accurately

determine the air cleaner element condition.

VENT HOLE

TOWARD DASH
NOTE:
t Before testing, inspect for holes or

breaks in the element, as these defects re-

quire immediate replacement. If no holes or

breaks exist, proceed as follows:

1.
Remove all hoses and plug all openings except air

cleaner inlet.

2.
Install air cleaner, using Tool J-7825 in place of the

wing nut. Screw Tool J-7825 onto the stud until it

seals tightly against the air cleaner cover. Rotate

the entire tool so that the scale can be read from

the left side of the car. Be sure the vent hole is

toward the dash.

3.
Connect a tachometer and place it so that it may be

read simultaneously with Tool J-7825.

4.
Zero oil level in the inner tube by pulling inner tube

upward until the rubber seal is above the vent hole,

then raise or lower as' required until the inner tube

oil level is exactly to the "0" mark.

5. Start engine. If engine is cold, allow to run for 2 to

3 minutes. The automatic choke must be fully open.

6. Accelerate the engine slowly until the inner tube oil

level of Tool J-7825 just reaches the 1/4 mark.

Allow engine speed to stabilize and note tachometer

(rpm) reading. Decelerate engine.

7. If the tachometer reading is at or below the follow-

ing, the oil wetted paper air cleaner element is re-

stricted beyond the allowable limit and should be

replaced. If testing indicates that the element

restriction is satisfactory at 12,000 miles, the ele-

ment need not be replaced but should be retested

every 6,000 miles thereafter until replaced.

Engine

Displacement

283 cu.
in.

327 cu.
in.

350 cu. in.

396 cu.
in.

427 cu.
in.
Horsepower

195

210

275

300

325

350

295

325

350

385

390

425
Minimum

Allowable

RPM

2300

2100

210Q

2600

2600

1550

1950

1850

1850

2140

Fig.
5A—Testing Air Cleaner
8. Remove tachometer and Tool J-7825 from vehicle

and push down inner tube until seal is below vent

hole to prevent oil loss.

Tool J-7825

FiHing
Tool

Tool J-7825 is shipped dry and must be filled with the

red gauge oil (specific gravity .826) provided.

Pull the knurled inner tube completely out of the gauge

and add oil to the reservoir until the oil level is between

CHEVROLET CHASSIS SERVICE /MANUAL