ENGINE SPECIFICATIONS

1957 Buick Engine Specifications

1957 Buick Engine Specifications

 

 

PISTON RINGS

1957

For your information two different style piston compression rings will be used in 1957. Approximately the first 15,000 engines will have compression ring with the inner chamfer “up “. Afterward all engines will be equipped with rings having the inner chamfer facing down. The new ring is designed to provide better high intake manifold vacuum oil control. Figure 1 shows a comparison view of both style compression rings on intake stroke. No difficulty should be encountered in identifying either style ring as both rings have “Top” stamped on the face of the ring.

1957 Buick Piston Rings

1957 Buick Piston Rings

All camshafts in 1957 are made of a cast iron alloy and cannot be used with any past model engine because the O.D. of the bearing journals on the 1957 camshaft have been increased approximately .100″ and cannot be installed in an engine. NOTE: The 1956 and 1957 distributor gears and valve lifters are interchangeable.

The 1957-40 series Synchromesh equipped cars have camshafts identified by a plain land just forward of the number 3 bearing journal. All other camshafts have 2 grooves in the land as indicated below. See Figure 2.

Series – 1957

40 Synchromesh – No Groove
All Dynaflow models – 2 Grooves

1957 Buick Camshaft Identification

1957 Buick Camshaft Identification

 

OIL CONSUMPTION

Following is a reprint of Special Service Letter, Dealer No. 212 dated May 29, 1957:

We have had a few complaints of oil consumption on our 1957 models. Most of these complaints are on engines driven less than 3,000 miles. It should be understood by all that new engines do consume an abnormal amount of oil during the break-in period or until piston rings have seated themselves. Actually, this is advantageous as it assures ample lubrication to the closely fitted parts of the new engine. Engine life is prolonged because of this abnormal consumption of oil during the break-in period. This fact should be explained to all new car purchasers.

If abnormal consumption is not reduced to normal after the break-in period, the following procedure should be followed:

  1. Check the entire engine carefully for oil leaks. This should be done with the engine at operating temperature. Correct any leaks found.
  2. Install intake valve seals. These seals should be installed on each intake valve as shown in Figure 3. Eight (8) pieces of Gr. 0.308, Part #1180942 should be ordered for one car and are now available at all warehouses.
1957 Buick Intake Valve

1957 Buick Intake Valve

The flat rate time for installing the seals is as follows:

Remove and replace both valve rocker arm shaft assemblies and install intake valve rubber seals – .9 hr.

If equipped with power steering, add .3 hr. to disconnect and connect belt and remove and replace the pump assembly.

If equipped with air conditioning, add .3 hr. to disconnect and connect the belt, remove and replace the rear compressor bracket, and to disconnect and connect the front brace.

These seals are not being used in production nor should they be installed in engines having normal oil consumption. The reason for this statement is that if the consumption is normal and seals are installed, the valve stems will run dry causing noise, valve stem scoring, and possibly valve sticking. Good judgment must be exercised in the use of these seals.

 

CHECKING TIMING MARK

We have received several reports stating that the timing marks were off location on the balancer of 1957 cars.

The quickest and easiest method of checking the timing mark location is to remove the spark plug from #1 cylinder and check the position of U.D.C. in relation to the timing mark on the balancer. This may be done by using an indicator with an extension through the spark plug hole to determine when #l piston is at U.D.C. At that point the timing mark should be at zero line.

If the timing mark on the balancer is susp2cted to be off, it may also be checked by removing the balancer and checking the timing mark in relation to the keyway. This can easily be done by drawing a straight line approximately 7″ long on a clean sheet of paper; then using a compass, draw a 1 7/16” diameter circle in center of straight line. See sketch in Figure 4.

1957 Buick Harmonic Balancer

1957 Buick Harmonic Balancer

Place balancer over circle drawn on paper so that centerline passes through center of balancer keyway as shown in Figure 9. The timing mark should be located .100″ (approx. 3/32″) clockwise from centerline at O.D. of balancer. See Figure 4.

 

LOW OIL PRESSURE

Following is a reprint of Special Red Band Service Letter, Dealer No. 190, dated November 12, 1956.

A few 1957 models have been reported to have low engine oil pressures. Investigation revealed that chips and burrs found in the oil pump relief valve restricted the operation of the check ball.

All 1957 model engines can, and should be checked for proper oil pressure by running the engine until it reaches normal operating temperature (approximately 15 minutes) and then run the engine at 1500 R .P.M. and note the oil pressure gauge reading on the instrument panel. lf the gauge reads half way or less it is advisable to remove the oil pump and check for burrs or chips on ball seat.

Do not take the gauge reading immediately after a cold start as the gauge may read high due to heavy oil consistency. The only true indication of low oil pressure is after the engine has reached normal operating temperature.

The ideal time to make this check would be at the conclusion of the road test following new car make-ready.

 

OVERHEATING COMPLAINTS

1957 Models

The following is a reprint of Special Service Letter, Dealer No. 208 dated April 22, 1957:

Engine overheating complaints with no coolant loss on both Air Conditioner and, non -Air Conditioner equipped 1957 cars have been traced to improperly calibrated thermo gauges. The original1957 gauge, #1513311, placed the pointer at the end of the normal bar at approximately 200° water temperature. It has been found that if a 1957 car is driven continuously in heavy city traffic at 90° air temperature, the water temperature will be about 200° F. This is still satisfactory since with the 15 pound pressure radiator cap the water boils at 250°. However, the driver is naturally worried since the temperature gauge indicates above normal temperatures.

Starting with car serial numbers listed below by assembly plants, the thermo gauges have been recalibrated to correctly register water temperatures.  Also, in the near future, a new gauge, Gr. 1.148 Part #1513541, which will have the white “N” (Normal) bar extended so that the pointer will not reach the end of the bar until the temperature is 240° F, will go into production.

Flint – 01082275
South Gate – 02028632
Linden  – 03029682
Kansas City – 04031066
Wilmington – 05024889
Atlanta – 06026986
Framingham – 07011490
Arlington – 08020711

Whenever a complaint is received on cars having lower serial numbers than those listed and the owner is alarmed because his temperature gauge is reading too high, the cooling system should be checked for leaks. If there are no leaks and proper coolant level is maintained, and thermo gauge still registers excessively high reading, then install a new thermo gauge, Gr. 1 .148 Part #1513541, which is available at all parts warehouses.

In the very near future, the Parts Department will issue a bulletin advising disposition of first type thermo gauges, Gr. 1.148 Part #1513311.

This is not a campaign and thermo gauges should be replaced only when complaints are received on those cars having lower serial numbers than those listed above.

 

LOW COMPRESSION ENGINES

South Gate Assembly Plant

A quantity of Series 50-60-70 engines having 9.5 to 1 compression ratio have been used in South Gate, California Assembly Plant in late 1957 production. This was done because of the lower octane fuels available on the West Coast as compared to the rest of the country.

The reduction in compression ratio from 10 to 1 to 9.5 to 1 is achieved by using Series 40 Dynaflow engine pistons. These 9.5 to 1 compression ratio engines may be identified by a letter “X” stamped in front of the Engine Manufacturing Code Number (not serial number). The Manufacturing Code Numbers of the first 9.5 to 1 compression ratio engines are:

Series 50-60 – X 376793
Series 70 – X 376813

Series 40 engines will not be affected by this change.

In the event a piston replacement is necessary on any engine in for service, first observe the Manufacturing Code Number to determine what compression ratio pistons are used and to insure that correct parts are installed.

Under no circumstances should 9.5 to 1 compression ratio pistons be installed to reduce detonation on an engine equipped with 10 to 1 pistons. If a detonation complaint is received on a 10 to 1 compression ratio engine, follow recommended service procedure outlined in BPS 2.421 dated March 8, 1957.

The Parts Department will continue to carry in stock replacement pistons for the 10 to 1 ratio engine.

CAUTION: If 10 to 1 ratio pistons are used with 9.5 to 1 pistons in the same engine, a very rough operating engine will result.

 

CRACKED BALANCER HUB

1957 Model

We have been advised that some mechanics are removing the harmonic balancer by tapping one side of the balancer with a hammer while prying on the other side. This practice must be discontinued, since tapping will crack the balancer hub in the area of the keyway slot, causing the balancer to become loose and noisy. The balancer may be removed by using two pry bars, one opposite the other; behind balancer. It is recommended that the end of each pry bar be placed as near to the crankshaft as possible to avoid cracking the hub.

 

ENGINE MOUNTING ADJUSTMENT

Engineering advises that whenever the engine is lifted enough to necessitate disconnecting the engine mounts, it is imperative that when the engine is lowered it be done so evenly in order to cradle the engine squarely between the mounting pads on the frame. This is to eliminate the chance that one mount may contact its frame pad first and be compressed and attached in a position which would allow bottoming (metal to metal contact) during full throttle operation. This condition may be checked on the car by observing whether the air-gaps on either side of each front mount are approximately the same. See Figure 5.

1957 Buick Engine Front Mounts

1957 Buick Engine Front Mounts

The engine and transmission when properly aligned with the frame of the car, must rest in a normal position which does not impose any shear strain on any of the rubber mounting pads. The following procedure should be used when tightening mounts to obtain proper adjustment.

  1. Make sure that transmission support to frame shims are in original position and that support to frame bolts are tight. Make sure that bolts holding thrust bracket to rear bearing retainer are tight. See Figure 6.
  2. Before tightening any other mounting bolts, check position of transmission thrust bracket; if it is tight against its thrust pad, engine and transmission fore -and -aft location is perfect and all other mounting bolts can be tightened.
  3. However, if there is a gap between the thrust bracket and its pad, proceed as follows:
    • Loosen 4 bolts holding engine mounts to frame.
    • Tighten 3 nuts holding thrust bracket to its pad. This will impose a forward strain on engine mounts.
    • Raise engine slightly to allow engine mounts to normalize. Then lower engine.
  4. Tighten 2 nuts holding transmission mounting pad to support.
  5. Tighten engine mounts to engine and to frame.

NOTE: When installing an engine or an engine­transmission assembly, the engine mounting pad to frame bolts should be the last mounting bolts to be tightened.

1957 Buick Transmission Support

1957 Buick Transmission Support

 

CYLINDER HEAD REMOVAL

1957 Non-Air Conditioned Cars

Due to the close clearance in the 1957 engine compartment, it is necessary to leave some of the cylinder head bolts and push rods in the head while removing same. The push rods should be pulled part way out and taped in position to hold them while the cylinder head is being removed. These same parts should be in the cylinder head upon reinstallation of the head.

1957 Air Conditioned Cars

Some question has been raised about the possibility of removing a 1957 cylinder head (right side) on an air conditioned equipped car without having to R&R the compressor from the car. Investigation of this matter has been completed and it was found that the right cylinder head can be removed without completely removing and replacing the compressor from the car.

The compressor front and rear brackets should be removed first to allow access to the rocker arm cover and assembly and the intake manifold assembly. Once the above items are removed from the car, the compressor assembly (all lines still attached) should be moved inward to the center of the engine as far as the lines will allow and tie (wire, rope, etc.) the compressor assembly to either the power steering pump or battery hold down strap. See Figure 7. With the compressor assembly in this position, the right exhaust manifold can be disconnected from the cylinder head and the lower cylinder head bolts can be removed. After all the lower cylinder head bolts have been removed, the compressor assembly should be moved up against the right inner fender skirt and supported by a wire, rope, etc., which can be attached to the right hood hinge. See Figure 8. With the compressor assembly in this position, the remaining cylinder head bolts and the cylinder head assembly can be removed from the car.

1957 Buick Cylinder Head Removal

1957 Buick Cylinder Head Removal

To replace the right cylinder head, reverse the above procedure.

A flat rate time of .8 hr. should be added to all engine operations which necessitate the R&R of the right cylinder head on air conditioner equipped cars.

1957 Buick Cylinder Head Removal Overview

1957 Buick Cylinder Head Removal Overview

 

CRANKSHAFT PULLEY INSTALLATION

(1957 Air Conditioner)

We have received a few reports whereby the crankshaft compressor driving pulley in 1957 Air Conditioner equipped cars were not assembled properly and resulted in pulley failure. It was found that the small diameter bolt holes in the pulley and reinforcement plate were over the rivets of the balancer, making it impossible for the pulley to seat firmly against balancer assembly.

Proper indexing of the six (6) harmonic balancer assembly rivets and the three (3) attaching bolt holes with corresponding holes in pulleys and reinforcement plate is very essential. If the pulleys are not properly installed, subsequent failure will result. Proper pulley installation may be determined by observing if no space exists between pulley bolting flange surface and balancer. If pulley is not tight against balancer, it is not installed properly. Since installation of reinforcement plate cannot be visually inspected, care must be exercised to make certain rivet clearance holes in the plate are located over rivets in the balancer.

 

DETONATION

1957 Models

A few detonation complaints on 1957 models have been reported. Whenever a complaint of this nature is encountered, it should be pointed out to the owner that in every city, fuel octane rating varies considerably and suggest that he try different brands of fuel until one having the highest octane rating is found. If, however, the owner is still not satisfied after trying different brands of fuels, the following procedure is recommended.

  1. The spark plug wiring arrangement should be checked to preclude the possibility of preignition. On 1957 models spark plug wires must be arranged to pass through the wire clips in the rocker arm covers in the same order as they are attached to the plugs. Spark plug wire numbers are stamped on clip to help insure correct wiring arrangement.
  2. Determine whether oil consumption is acceptable. : Some brand new engines may use various quantities of oil until the compression rings become fully seated. In some instances it may take 2000 to 3000 miles before oil consumption ceases. If an owner complains of excessive oil consumption and no external leaks are evident, the engine should be run until it has accumulated at least 3000 miles of operation before attempting mechanical repairs. If oil consumption persists after 3000 miles contact the Zone Office for further instructions.
  3. Check engine for vacuum leaks and note if intake manifold gaskets are installed properly as described in BPS 2.418; correct leaks if found. A quick check to determine if a vacuum leak exists in vacuum lines other than the engine is to disconnect vacuum line from intake manifold and hold finger over opening in manifold fitting. If engine smooths out when this is done, it indicates that a vacuum line leak exists. If engine does not smooth out after performing the above check and engine is still suspected of having a vacuum leak, squirt light oil around edges of intake manifold where it rests on cylinder head. If engine smooths out when this is done, it indicates a vacuum leak which should be corrected.
  4. Check initial distributor setting. If it is not set at 5° advance, reset to this figure. (In checking timing make sure distributor vacuum advance line has been disconnected).
  5. Check to see if centrifugal and vacuum advance of distributor fall within specified limits. Also, check distributor for dwell angle variation. Dwell angle should not vary more than three degrees total between idle speed and 1500 RPM. Follow the dwell meter manufacturer’s recommendations for calibration and use of the dwell meter. Do not exceed 1500 engine RPM as some dwell meters are not accurate at higher speeds.
  6. If the above changes do not help eliminate detonation the initial spark setting may be retarded to T.D.C. without any noticeable loss in car performance or economy.
  7. If the preceeding steps do not make the car passable, then carbon blast the cylinder chambers in exact accordance with operating instructions accompanying each Kent – Moore “Head-On” Carbon Blaster. Kent-Moore, Inc. is making available a new distributor Gauge J 5995-55 for use in the 1957 distributors. This gauge is priced at $6.50 each and may be ordered from the Kent Moore, Inc., 28635 Mound Road, Warren, Michigan.
  8. If, after performing the above procedure and the job is still not passable, replace the cylinder head gaskets with those having .045” thickness.

 

RADIATOR & FAN SHROUD CLEARANCE

1957 -All Air Conditioned Cars

Engine cooling can be improved and fan noise reduced on air conditioned cars by locating the fan shroud assembly closer to the radiator assembly.

The following steps are necessary to accomplish this improvement in cooling and fan noise:

  1. Remove fan shroud assembly and fan shroud mounting brackets.
  2. Remove 7/32 inches of material from the lower tang of the fan shroud mounting brackets (See Figure 9).
  3. Elongate three holes on each side of fan shroud assembly by 1/4 inch. (See Fig. 10).
  4. Reinstall fan shroud mounting brackets.
  5. Reinstall fan shroud assembly so it contacts the radiator core, and tighten all bolts.
  6. This change is being made in production.
1957 Buick Radiator

1957 Buick Radiator

1957 Buick Radiator Clearance

1957 Buick Radiator Clearance

 

FOREIGN TRAVEL WITH DOMESTIC BUILT CARS

Owners contemplating travel outside the United States should be cautioned to check on the quality of the fuel available before their trip. Our Engineering Department advises that the domestic 1957 Buick engine equipped with Dynaflow transmission requires a minimum octane fuel of 98 while the 40 series equipped with Synchromesh transmission requires 91 octane fuel to operate satisfactorily.

If satisfactory fuels cannot be assured, the compression ratio should be lowered by installing export pistons and head gaskets.

1957 Buick Engine Compression Ratio

1957 Buick Engine Compression Ratio

The 40 series domestic and export engines with Synchromesh transmission and compression ratio of 8.0 – 1 uses the same piston, Gr. 0.629 Part #1392769 and standard .015″ cylinder head gasket, Gr. 0.289 Part #1173568. The 8.5 – 1 compression ratio on all export Dynaflow jobs is obtained by using piston Gr. 0.629 Part #1392950 and .015″ cylinder head gasket. However, the .045″ cylinder head gasket Gr. 0.289 Part #1173567 may be installed to lower the compression ratio even farther if necessary on both the Synchromesh and Dynaflow.

Fuel octane values in general are much lower outside the continental limit of the U.S. Therefore, Buick owners contemplating foreign travel should be cautioned to check on available fuels before beginning their trip. Inquiries pertaining to fuels in foreign countries may be obtained by writing to the Service Department, G. M. Overseas Operations, G. M. Building, Detroit 2, Michigan.

Note: Engine damage caused by detonation as a result of the use of low octane fuels is not considered a defect in material or workmanship; therefore, cannot be considered for warranty adjustment.

 

FAN DRIVEN PULLEY CHANGE

For 1957 Air Conditioned Cars

To improve the air flow on air conditioned cars, the diameter of the fan driven pulley has been reduced. This change applies to both the 1-groove and 2 -groove pulleys and reduces the length of the air conditioner compressor belt. The first 700 air conditioning packages which were built and sold through the Parts Department included the first type pulleys and belt and all packages built after approximately January 15, include the new small pulleys and belt. Following are the parts involved:

First Type Packages Include:

1-Gr. 1.406-1166161 Pulley-Fan Driven 2-Groove
1-Gr. 1.406-1175261 Pulley-Fan Driven 1-Groove
1-Gr. 9.185-1175076 Compressor Drive Belt

Second Type Packages Include:

1-Gr. 1.406 – 1179390 Pulley-Fan Driven 2-Groove
1-Gr. 1.406-1179391 Pulley-Fan Driven 1-Groove
1-Gr. 9.185-1179392 Compressor Drive Belt

Either the first or second type parts must be used in sets in order to insure the proper pulley to belt relationship. This same change will be made on production built air conditioned jobs approximately February 1. Both the first and second type parts will be stocked for service replacement use.

Some of the late Air Conditioner Packages may have been shipped with the new pulleys and first type longer belt. If any packages are received with the incorrect belt, the correct belt should be ordered from your normal shipping warehouse. The belts have the part number moulded on the outside edge for identification.

When using the new pulleys 1179390 and 1179391, the single groove pulley is installed in front of the two groove pulley. Both pulleys are used on all cars when installing air conditioning and if the car is not equipped with Power Steering, one groove of the two groove pulley will be empty.

 

1957 FAN SHROUDS

At the start of 1957 production, two types of Fan Shrouds were used. A full type fan shroud was used on air conditioned cars and a ring type fan shroud was used on all other cars. Shortly after production started, the full type fan shroud was cancelled for 1957 usage and the ring type shroud was used on all cars. The ring type fan shroud will be used for service replacements on cars originally equipped with the full type fan shroud. When installing the ring type fan shroud on cars originally using a full type fan shroud, it will be necessary to use two fan shroud mounting brackets, Group 1.260 Part #1178198 and 1178199.

The fan shrouds involved are as follows: Group 1.260 Part #1178037 (Full Type)

Replaced by:

Group 1.260 Part #1174402 (Ring Type) in later 1957 production, starting in March, a new wider radiator was used on air conditioned cars.

At the time this new radiator was used, a new full type fan shroud, Group 1.260 Part #1179450, was released for use with this new wider radiator. This new full type fan shroud, which also uses mounting brackets 1178198 and 1178199, will be stocked for service replacements on after- jobs air conditioned equipped cars.

 

RADIATOR INFO

1957 Model

Because of the various radiators and shrouds used on 1957 model cars we have prepared this bulletin to clarify their use.

The radiators may be identified by their part number which is stamped in the top tank as shown in Figure 11.

1957 Buick Radiator Identification

1957 Buick Radiator Identification

All 1957 Dynaflow standard production jobs are equipped with radiator 3136705. Series 40 Synchromesh are equipped with radiator 3136704. All Dynaflow air conditioner equipped cars use radiator 3138904. This same radiator is used when heavy duty cooling is specified on a new car order. All of these radiators use the ring type shroud with the exception of a very few early production Dynaflow jobs which used the full shroud.

 

LOCATION OF DRIVING BOLT HOLES

CONVERTER TO FLYWHEEL

In order to determine the correct location of converter to flywheel driving bolts during installation of converter cover, turn cover so that the drain plugs are in horizontal plane, with seven bolt holes above and eight bolt holes below the plugs. The upper-center bolt hole, and the second hole below each drain plug are the three (3) drive bolt holes. Install four cover attaching bolts on each side of the upper-center hole, and four bolts in the four lowest holes. See Figure 12.

These bolts should be installed with lock washers and tightened to approximately 5 ft. lbs. torque in numerical sequence shown in Figure 12. Final torqueing of these bolts 25-30 ft. lbs. should be made in the same sequence ad mentioned above.

1957 Buick Driving Bolts

1957 Buick Driving Bolts

 

BALANCER CHANGE

1957 After Jobs

An after job change was made in the 1957 harmonic balancer hub and pulley arrangement, in that the pulleys are held on the balancer by six (6) attaching bolts instead of three (3) previously used. See Figure 13.

The change was made to provide additional strength and prevent cracks from occurring at the bolt holes of the pulley.

The old balancer assembly Gr. 0.659, Part No. 1173780 and reinforcement plate Gr. 0.660, Part No. 1180959 will be replaced by the new six (6) hole balancer and plate when stock of the old balancer and plate is exhausted. The fan driving pulleys will be serviced separately and should be used with correct balancer.

Listed below are pulleys involved:

1957 Buick Balancer Part Numbers 3-Hole

1957 Buick Balancer Part Numbers 3-Hole

1957 Buick Balancer Part Numbers 6-Hole

1957 Buick Balancer Part Numbers 6-Hole

1957 Buick Balancer Holes

1957 Buick Balancer Holes

 

FAN DRIVING PULLEY & HARMONIC BALANCER CHANGES

1957

For your information and to prevent any misunderstanding and unnecessary replacement of parts the following changes have been made in the fan driving pulley and harmonic balancer on 1957 cars.

FAN DRIVING PULLEY

At the start of production, the fan driven pulley was attached to the harmonic balancer with bolts equipped with a flat washer against the pulley and lock washer between bolt head. The flat washer was used in early 1957 production to prevent the lock washer from cutting into the pulley when attaching bolts were tightened. In later production a reinforcement plate, Gr. 0.660 Part number 1179792, was used on all jobs to replace the flat washer, and the pulley attaching bolts were increased in length from 5/16 – 18 x 7/8 to 5/16 -18 x 1. However, it was decided to install two (2) reinforcement plates (each .060″ thick) on air conditioner-equipped jobs to add additional support to pulley bolting flange. See Figure 14. The latest change in production is the installation of one (1) plate .090″ thick, Gr. 0.660 Part #1180959, on air conditioner-equipped jobs. At a later date, for the purpose of standardizing production parts, the .090″ thick plate also will be used on non air conditioner-equipped cars. Therefore, when servicing a crankshaft pulley on an air conditioner-equipped job, it is important to make sure that it is equipped with two (2) .060″ plates or one (1) .090″ plate. It is also very important that one-inch bolts and lock washers be used when installing the reinforcement plate. If the jobs originally had flat washers under the lock washer, discard them. It is not necessary to change non air conditioner-equipped cars equipped with flat washers to either thickness reinforcement plate; however, if for any reason a change is made, one-inch long bolts Gr. 0.662 Part #1171530 should be used.

1957 Buick Air Conditioner Fan Driving Pulley Arrangement

1957 Buick Air Conditioner Fan Driving Pulley Arrangement

HARMONIC BALANCER

During the first part of 1957 production, the pulley attaching bolt holes in the balancer were tapped to a depth of .56″ to accommodate the 7/8″ long bolt. When the one inch long bolts were used, the depth of the holes was increased to .72”. It is, therefore, important whenever servicing the crankshaft driving pulleys to make certain pulley attaching bolts are firmly tightened to 15 to 20 ft. lbs. of torque, and that bolts do not bottom in balancer. If bolts bottom in balancer holes, pulleys will be loose and subsequent failure may result. If pulley is loose after being torqued, inspect balancer tapped holes for chips or foreign material which would prevent bolts from seating fully.  Also, if necessary, retap holes to sufficient depth to prevent bolts from bottoming.

ADJUSTING BELT TENSION

Engineering has recommended that belt tension adjustment be performed with a torque wrench at the pulley of the generator and power steering pump as follows:

  1. Engine Fan Belt – Tighten belt until 20 to 25 ft. lbs. of torque slips generator pulley on belt.
  2. Power Steering Belt – Tighten belt until 30 to 35 ft. lbs. of torque slips belt at power steering pump pulley.
  3. Air Conditioner Compressor Belt – Tighten compressor belt so that normal thumb pressure applied midway between fan and compressor pulleys deflects belt approximately 3/8 inch.

 

VACUUM PUMP NOISE

Several reports have been received stating that 1957 engine vacuum pumps are noisy when engine is cold and in most cases the noise diminishes when engine becomes warm. The source of trouble has been traced to high oil level in crankcase.

Due to the design of the oil pan and pump assembly when oil level is high, the vacuum discharge opening in pump body is submerged in oil allowing fluid to run down into the vacuum section. When this happens, the pumping action which takes place during initial running of cold engine causes the pump to knock while oil is being discharged from the vacuum section. In order to determine if the vacuum pump is the source of trouble, disconnect vacuum pump hose from windshield wiper motor and hold finger over end of hose with engine idling. If noise is present when finger is held over opening in hose and disappears when released, the trouble is that outlined above. NOTE: Noise may be prominent when oil is cold and thick and hardly audible when warm.

Whenever this condition is encountered, it is important to check oil level with car on level floor and if necessary drain crankcase to bring oil level down to “FULL” mark on engine dip­stick (oil gauge rod). Care also should be exercised to make certain that dipstick is fully seated when oil level check is made.

To help eliminate this condition in production, engines having code numbers higher than 129976 or code numbers between 109982 and 127199 inclusive will have a steel tubing pressed in pump body discharge opening so that approximately 3/4 ‘ ‘ extends above casting. At a later date, pump body castings will be changed and a boss added so that the discharge opening will be approximately 5/8″ higher than that of first type pump bodies without the steel tubings.

On early production engines it is suggested that whenever the engine oil pan or oil-vacuum pump assembly is removed, a 5/16″ diameter thin wall steel tubing be soldered in the pump body so that approximately 3/4″ extends out of casting.

The following method is recommended to install the 5/16″ diameter thin wall tubing:

  1. Remove oil pump housing from vacuum section of pump by removing (7) screws, two of which are under oil screen.
  2. File casting surface around vacuum discharge hole so solder will have a good bonding surface.
  3. Cut the 5/16″ diameter tubing approximately 1 1/4″ long, and install it in the pump body discharge opening, so that 3/4″ extends above the housing. See Figure 15.
1957 Buick Vacuum Pump

1957 Buick Vacuum Pump

  • Solder tubing in place making sure no filings or solder has dropped into the vacuum passage.
  • CAUTION: Do not use acetylene or arc welding equipment as distortion of casting may result due to excessive heat.

    Flat rate time allowed for installing the tube in the oil pump with pump removed is.3 hours; includes disassembling of oil pump from vacuum section.