Page 305 of 659

ENGINE 6-40
SPECIAL TOOLS
Fig.
2T - Engine Special Tools
1. J-4536
2.
J-1264
J-8058
J-5853
3.
J-8087
4.
J-8001
5.
J-7316
6. J-8037
7.
J-8020
J-8021
J-8032
J-22249
J-22147
J-22250
8. J-6994
9. J-9510
10.
J-5239
J-6305
J-8062
J-8101
J-5830
J-7049
14.
J-8089
11.
12.
13.
Engine Lift Kit
(0-200 ft. Ib.) Torque Wrench
(0-50 ft. Ib.) *
(0.-100 in. Ib.)
Indicator Set (Cylinder Bore)
Indicator Set (Universal)
Belt Tension Gauge
Piston Ring Compressor
(3 9/16") Piston Ring Expander
(3 7/8")
(4")
(3 15/16")
(4 3/32")
(4 1/4")
Piston Pin Assembly Tool
Piston Pin Assembly Tool
(3/8") Connecting Rod Guide Set
01/32") m
Valve Spring Compressor
Valve Guide Cleaner
(11/32") Valve Guide Reamer Set
(3/8")
Carbon Removing Brush
. 15. J-5860
16.
J-5715
J-6036
17.
J-6880
18.
J-5802
19.
J-9534
20.
J-9535
21,
J-22144
22.
J-8369
23.
J-6098
24.
J-0971
25.
J-6978
26.
J-22197
27.
J-21058
28.
J-1619
29.
J-5825
30.
J-8105
31.
J-5590
32.
J-0966
33.
J-21742
34.
J-22102
35.
J-8340
36.
J-5595
Cylinder Head Bolt Wrench
(.003") Rocker Arm Stud Reamer
(.013")
Rocker Arm Stud Installer
Rocker Arm Stud Remover
Distributor Lower Bushing Remover
Distributor Lower Bushing Installer
Oil Pick-up Screen Installer
Oil Pick-up Screen Installer
Cam Bearing Tool
Camshaft Gear Support
Torsional Damper Puller
Torsional Damper Installer
Torsional Damper and Sprocket Installer
Crankshaft Sprocket Puller
Crankshaft Sprocket Puller
Crankshaft Gear Puller
Crankshaft Sprocket or Gear Installer
Crankcase Cover Centering Gauge
Crankcase Cover Centering Gauge
Crankcase Cover Tool
Grankcase Cover Seal Installer
Crankcase Cover Seal Installer
CHEVROLET CHASSIS SERVICE MANUAL
Page 306 of 659

SECTION 6K
ENGINE COOLING
INDEX
Page
General Description . . . 6K-1
Maintenance and Adjustments 6K-1
Coolant Level 6K-1
Coolant System Checks 6K-1
Periodic Maintenance 6K-2
Cleaning 6K-2
Reverse Flushing 6K-2
Radiator 6K-2
Page
Cylinder Block and Cylinder Head 6K-2
Hot Water Heater 6K-2
Fan Belt . 6K-2
Adjustment ....". 6K-2
Thermostat . 6K-2
Replacement 6K-2
Water Pump. . . . 6K-3
Removal 6K-3
Installation 6K-3
GENERAL DESCRIPTION
A pressure cooling system is provided for on all
models by a pressure type radiator cap (fig. 1). The
pressure type radiator cap used is designed to hold a
pressure above atmospheric pressure in the cooling
system. Excessive pressure is relieved by a valve within
the cap that opens to radiator overflow.
The water pump is a ball bearing, centrifugal vane
impeller type. It requires no care other than to make
certain the air vent at the top of the housing and the drain
holes in the bottom do not become plugged with dirt or
grease. Removal and installation of the water pump is
covered in this section. For overhaul procedures of the
water pump refer to Section 6K of the Passenger Chassis
Overhaul Manual.
For radiator, refer to Section 13 of this manual For
radiator shroud, refer to Section 11 of this manual.
Fig.
I—Pressure Radiator Cap
MAINTENANCE AND ADJUSTMENTS
Coolant Level
The radiator coolant level should only be checked when
the engine is cool, particularly on cars equipped with air
conditioning. If the radiator cap is removed from a hot
cooling system, serious personal injury may result
The cooling system fluid level should be maintained
one inch below the bottom of the filler neck of the radia-
tor when cooling system is cold, or at the bottom of the
filler neck when the system is warm. It is very impor-
tant that the correct fluid level be maintained. The seal-
ing ability of the radiator cap is affected when the cooling
level is too high.
All passenger car cooling systems are pressurized
with a pressure cap which permits safe engine operation
at cooling temperatures of
up
to 247°F.
When the radiator cap is removed or loosened, the
system pressure drops to atmospheric, and the heat
which had caused water temperature to be higher than
212°F, will be dissipated by conversion of water to
steam. Inasmuch as the steam may form in the engine
water passages, it will blow coolant out of the radiator
upper hose and top tank, necessitating coolant replace-
ment Engine operating temperatures higher than the
normal boiling point of water are in no way objectionable
so long as the coolant level is satisfactory when the
engine is cooL
Upon repeated coolant loss, the pressure radiator cap
and seat should be checked for sealing ability. Also, the
cooling system should be checked for loose hose con-
nections, defective hoses, gasket leaks, etc.
Coolant System Checks
1.
Test for restriction in the radiator, by warming the
engine up and then turning the engine off and feeling
the radiator. The radiator should be hot at the top
and warm at the bottom, with an even temperature
rise from bottom to top. Cold spots in the radiator
indicate clogged sections.
2.
Water pump operation may be checked by running the
engine while squeezing the upper radiator hose. A
pressure surge should be felt Check for a plugged
vent-hole in pump.
NOTE:
A defective head gasket may allow ex-
haust gases to leak into the cooling system.
This is particularly damaging to the cooling
system as the gases combine with the water to
form acids which are particularly harmful to
the radiator and engine.
3.
To check for exhaust leaks into the cooling system,
drain the system until the water level stands just
above the top of the cylinder head, then disconnect
the upper radiator hose and remove the thermostat
and fan belt. Start the engine and quickly accelerate
several times. At the same time note any appreci-
able water rise or the appearance of bubbles which
CHEVROLET CHASSIS SERVICE MANUAL
Page 307 of 659

ENGINE COOLING 6K-2
are indicative of exhaust gases leaking into the coolr
ing system.
Periodic Maintenance
Periodic service must be performed to the engine cool-
ing system to keep it in efficient operating condition.
These services should include a complete cleaning and
reverse flushing as well as a reconditioning service.
In the course of engine operation, rust and scale ac-
cumulate in the radiator and engine water jacket. The
accumulation of these deposits can be kept to a minimum
by the use of a good rust inhibitor but it should be
remembered that an inhibitor will not remove rust al-
ready present in the cooling system.
Two common causes of corrosion are: (1) air suction--
Air may be drawn into the system due to low liquid level
in the radiator, leaky water pump or loose hose con-
nections; (2) exhaust gas leakage—Exhaust gas may be
blown into the cooling system past the cylinder head
gasket or through cracks in the cylinder head and block.
Cleaning
A good cleaning solution should be used to loosen the
rust and scale before reverse flushing the cooling
system. There are a number of cleaning solutions avail-
able and the manufacturer's instructions with the particu-
lar cleaner being used should always be followed.
An excellent preparation to use for this purpose is GM
Cooling System Cleaner. The following directions for
cleaning the system applies only when this type cleaner
is-used.
1.
Drain the cooling system including the cylinder block
and then close both drain plugs.
2.
Remove thermostat and replace thermostat housing.
3.
Add the liquid portion (No. 1) of the cooling system
cleaner.
4.
Fill the cooling system with water to a level of about
3 inches below the top of the overflow pipe.
5. Cover the radiator and run the engine at moderate
speed until engine coolant temperature reaches 180
degrees.
6. Remove cover from radiator and continue to run the
engine for 20 minutes. Avoid boiling.
7. While the engine is still running, add the powder
portion (No. 2) of the cooling system cleaner and
continue to run the engine for 10 minutes.
8. At the end of this time, stop the engine, wait a few
minutes and then open the drain cocks or remove
pipe plugs. Also remove lower hose connection.
CAUTION: Be careful not to scald your hands.
NOTE:
Dirt and bugs may be cleaned out of
the radiator air passages by blowing out with air
pressure from the back of the core.
Reverse Flushing
Reverse flushing should always be accomplished after
the system is thoroughly cleaned as outlined above.
Flushing is. accomplished through the system in a direc-
tion opposite to the normal flow. This action causes the
water to get behind the corrosion deposits and force
them out.
Radiator
1.
Remove the upper and lower radiator hoses and re-
place the radiator cap,
2.
Attach a lead-away hose at the top of the radiator.
3.
Attach a new piece of hose to the radiator outlet
connection and insert the flushing gun in this hose.
4.
Connect the water hose of the flushing gun to a water
outlet and the air hose to an air line.
5. Turn on the water and when the radiator is full, turn
on the air in short blasts, allowing the radiator to
fill between blasts of air.
CAUTION: Apply air gradually as a clogged
radiator will stand only a limited pressure.
6. Continue this flushing until the water from the lead-
away hose runs clear.
Cylinder Block and Cylinder Head
1.
With the thermostat removed, attach a lead-away
hose to the water pump inlet and a length of new hose
to the water outlet connection at the top of the engine.
NOTE:
Disconnect the heater hose when re-
verse flushing engine.
2.
Insert the flushing gun in the new hose.
3.
Turn on the water and when the engine water jacket
is full, turn on the air in short blasts.
4.
Continue this flushing until the water from the lead-
away hose runs clear.
Hot Water Heater
1.
Remove water outlet hose from heater core pipe.
2.
Remove inlet hose from engine connection.
3.
Insert flushing gun and flush heater core. Care must
be taken when applying air pressure to prevent
damage to the core.
Fan Belt
Adjustment
1.
Loosen bolts at Delcotron slotted bracket.
2.
Pull Delcotron away from engine until desired ten-
sion reading is obtained with a strand tension gauge.
Refer to Section 6, "Engine Tune-Up".
3.
Tighten all Delcotron bolts securely.
Thermostat
The thermostat consists of a restriction valve actuated
by a thermostatic element. This is mounted in the hous-
ing at the cylinder head water outlet above the water
pump,
thermostats are designed to open and close at
predetermined temperatures and if not operating properly
should be removed and tested as follows.
Replacement
1.
Remove radiator to water outlet hose.
2.
Remove thermostat housing bolts and remove water
outlet and gasket from thermostat housing (fig. 2).
3.
Inspect thermostat valve to make sure it is in good
condition.
4.
Place thermostat in hot water 25° above the temper-
ature stamped on the thermostat valve.
5. Submerge the valve completely and agitate the water
thoroughly. Under this condition the valve should
open fully.
6. Remove the thermostat and place in water 10° below
temperature indicated on the valve.
7. With valve completely submerged and water agitated
thoroughly, the valve should close completely.
8. If thermostat checks satisfactorily, re-install, using
a new housing gasket.
9. Refill cooling system.
CHEVROLET CHASSIS SERVICE MANUAL
Page 308 of 659

ENGINE COOLING 6K-3
Fig.
2— Replacing Thermostat
Water Pump
Removal
1.
Drain radiator and break loose the fan pulley bolts.
2.
Disconnect heater hose, lower radiator hose and
by pass hose (as required) at water pump.
3.
Loosen Delcotron and remove fan belt then remove
fan bolts, fan and pulley.
4.
Remove pump to cylinder block bolts and remove
pump from engine.
NOTE:
On in line engines, pull the pump
straight out of the block first, to avoid damage
to impeller.
Installation
1.
Install pump assembly on cylinder block and tighten
bolts securely. Use on new pump to block gasket(s).
2.
Install pump pulley and fan on pump hub and tighten
bolts securely.
NOTE:
A guide stud (5/16"-24 x 1-1/2" bolt
with the head removed) installed in one hole of
the fan hub will aid in aligning hub, pulley and
fan.
Remove stud after starting the remaining
three bolts.
3.
Connect hoses and fill cooling system.
4.
Install fan belt and adjust as previously outlined.
5. Start engine and check for leaks.
CHEVROLET CHASSIS SERVICE MANUAL
Page 309 of 659

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
Page 310 of 659
ENGINE FUEL
6M-2
ROCHESTER
BV
IDLE
SPEED
IDLE
MIXTURE
ROCHESTER
2GV
HOLLEY 2300C
(PRIMARY)
IDLE
MIXTURE
SPEED
HOLLEY 2300
(SECONDARY)
IDLE IDLE
MIXTURE SPEED
MANUAL
CHOKE CART
R YF
AUTOMATIC CHOKE
IDLE
SPEED
IDLE
MIXTURE
IDLE
MIXTURE
IDLE
SPEED
ROCHESTER
4MV
IDLE
SPEED
IDLE
MIXTURE
SIDE INLET
HOLLEY
4150
CENTER INLET
IDLE
MIXTURE
IDLE
MIXTURE
IDLE
SPEED
HOLLEY
4160
IDLE
MIXTURE
IDLE
SPEED
APPLICATION
CARBURETOR
U
IN LINE
153
90
194
120
230
140
250
155
V-8
283
195
210
327
275 300 325 350
350
295
396
325 350
427
385 390 400 425 435
ROCH.
BV
1234
ROCH
2GV
1234
ROCH
4MV
1234
1-2
CARTER
YF
Man.
Auto.
2-4
1234
HOLLEY
4150
Side
Center
HOLLEY
4160
HOLLEY
2300
C Prim.
Sec.
Fig.
1C
—Carburetors
CHEVROLET CHASSIS SERVICE MANUAL
Page 311 of 659

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
Page 312 of 659

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