Following are the latest carburetor specifications for 1954 and 1955. Rather than list the individual changes we are reprinting the specifications for both Carter and Stromberg carburetors. These are the latest complete specifications available at this time.
CARTER CARBURETOR & CHOKE CALIBRATIONS 1954
IMPORTANT: Calibrations are governed by the CODE number on the attached code tag.
NOTE: If Code No. 2179S appears on a Carter two barrel carburetor, see the 1955 specification. The fast idle cam adjustment, Paragraph 3-17, Step 7, Sub-paragraph (a) and (b) of the 1954 Shop Manual should be changed to read as follows:
- If carburetor is on engine, turn adjustment screw to obtain engine speed of 1800 RPM. See Figure 3-26.
- If carburetor is on bench, turn adjustment screw until .028″ (Series 40-50) or .018″ (Series 60-70-M/100) wire gauge just can be inserted between edge of throttle valve and wall of body flange diametrically opposite the idle ports.
NOTE: The RPM change in Sub-paragraph (a) and the gauge setting in Sub-paragraph (b) above should also be made in the 1955 Shop Manual.
The recommended hot idle speed for both two and four barrel carburetors still remains at 450 RPM.
STROMBERG CARBURETOR & CHOKE CALIBRATIONS 1954
IMPORTANT: Calibrations are governed by the Code number stamped on air horn directly above the fuel level sight plug.
CARTER CARBURETOR & CHOKE CALIBRATIONS 1955
IMPORTANT: Calibrations are governed by the CODE number on the attached code tag.
*NOTE: Beginning with Carter Carburetor Inspection Tag Identification Number (A-5) the low speed jet on the 2179S carburetor will be changed from a No. 69 drill to a No. 66 drill.
STROMBERG CARBURETOR & CHOKE CALIBRATIONS 1955
STROMBERG CARBURETOR – ADJUSTMENT OF FAST IDLE – CAM AND CHOKE UNLOADER
If the engine operates on fast idle too long after starting or else moves to slow idle too soon, or the choke unloader does not operate properly, adjust fast idle cam and choke unloader as follows:
IMPORTANT: Calibrations are governed by the CODE number stamped on air horn directly above the fuel level sight plug.
- Remove air cleaner and silencer.
- Place a No. 54 drill between wall of air horn and the center of upper edge of choke valve, and hold valve firmly closed against the drill. See figure 18 (A).
INTAKE MANIFOLD REPLACEMENT
As soon as 1954 intake manifold stock supplies are exhausted, the 1955 intake manifold will be used as a field replacement on the 1954 models. This change will affect air conditioned jobs because the boss on the manifold for the rear compressor bracket is raised 0.32″ on the 1955 manifold.
It will be necessary to mill down this boss when replacing a 1954 intake manifold with a 1955 on air conditioned jobs.
FUEL PUMP ARM BREAKAGE
Bent and Broken
A few cases of bent or broken fuel pump arms have been reported from the field. This condition can be caused by interference of fuel pump arm and casting flash in the timing chain cover. See Figure 19.
Installation of a new fuel pump will not correct this condition. The timing chain cover should be removed and the casting flash removed with a file or chisel. The fuel pump cam should be checked for excessive wear due to abnormal loading. The fuel pump arm will show evidence of any interference at point approximately 1 1/2 inches from the fuel pump body.
1954-55 SERIES 40 SYNCHROMESH CARS
Suggested procedure for correction of poor performance during warm-up 1954 and 1955 Series 40 Synchromesh. (Synchromesh – 40 Series equipped with Carter two barrel carburetors.)
The following procedure will be found effective in improving engine performance during warm-up and minimizing uneven running at 15-18 mph steady throttle on 1954 and 1955 synchromesh 40 Series cars. (Not effective as a correction for carburetor icing)
Remove intake manifold – inspect for casting flash in cylinder head exhaust cross-over passages. Follow information given in BPS 2.381, Page 55.
Tune engine, (including check compression) then check and correct spark plug wire location and make sure there are no vacuum leaks. See Shop Manual for proper spark plug wire location.
Check carburetor – Carburetors used on 1954 models were 2081S, 2081SA and 2179S. Carburetor for l955 models is 2179S.
If car is equipped with 2081S, check for proper metering rods. These should be 75-1107. (Specifications included in this BPS issue) In addition, install kit, Group 3.783, Part #1392064 as outlined in BPS 2.368 page 156 to bring this carburetor to 2081SA specification.
Check fuel level and adjust if necessary to make sure fuel is at bottom of sight plug hole.
Check pump stroke and metering rod settings and adjust if necessary.
Set choke thermostat housing cover two notches lean. (Due to variation in fuels, individual engines may require some variation in choke setting, however, adjustment should never exceed three notches lean.)
Adjust for good idle at 450 RPM. Be sure idle setting is not too lean.
1955 Carter and Stromberg
Following is a reprint of Special Red Band Service Letter, Dealer No. 160 dated August 9, 1955.
All Buicks built after about August 1, 1955, will include a new feature which is designed to overcome stalling caused by carburetor icing. This feature consists of a new intake manifold having two holes drilled into the exhaust gas cross-over. A channel connecting these two holes forms an exhaust passage. New carburetors are designed to conduct the exhaust gas heat up from this passage into the throttle body to prevent ice formation around the throttle valve area.
Both 4-barrel carburetors (Carter and Rochester) achieve this by use of new throttle bodies; all other parts of the carburetors remain the same so there are no new specifications or adjustments. (See Figure 20).
However, both 2-barrel carburetors (Carter and Stromberg) are completely new in design. They have an offset bowl with a single float, a lower over-all design, and contain a new throttle body which will readily conduct the exhaust gas heat provided by the new intake manifold to the throttle valves.
Since both 2-barrel carburetors are entirely new, they have all new adjustments which are as follows:
- Float Level – 3/16” below top edge of bowl (no Gasket)
- Pump Plunger – 1” from top of plunger offset to bowl cover with pump rod in long stroke hole
- Start-Aid with choke closed on #53 drill, start-aid should just clear
- Choke OnLoader – #27 drill between choke and air horn
- Fast Idle Speed with throttle stop screw 5 turns in from closed throttle position, fast idle lever should clear high step of cam by #48 drill
- Choke Spring Pick-Up Lever with throttle stop screw 7 turns in from closed throttle position, pick-up lever should just contact choke spring
- Fast Idle Cam with choke closed, fast idle lever should clear cam end lug by 0 – .020″
- Choke Positioning Lever with throttle closed, choke should open to admit #5 drill
- Choke align index marks
- Float Level – 1/4″ from bowl cover (no gasket)
- Pump Plunger with throttle closed, pump arm horizontal-link in long stroke hole
- Metering Rod with throttle closed and rods bottomed, revolve metering rod arm up and tighten set screw
- Fast Idle Cam with choke closed, .020” clearance between choke shaft outer and inner levers
- Choke Unloader – 3/16” drill between choke and air horn
- Fast Idle Speed – engine warm-in neutral- on high step of cam-turn fast idle screw to get 1300 RPM
- Choke – align index marks
Note: Intake manifold gasket exhaust hole reduced to 1/2” with this change (Dynaflow Jobs Only). Synchromesh jobs use gasket with 5/8″ hole.
More complete servicing information is covered in DOT Film, 55-15 and 55-16. In addition to the film, a handbook, B.P.S. 7.30, which is part of the DOT film package, contains servicing information for both Carter and Stromberg carburetors.
Three copies of the handbook are included in each dealer package of the DOT films which will be received by dealers approximately August 30, 1955. All dealers not subscribing to the DOT program will be sent at least one copy of the booklet from their local zone office.
The new WGD Carteroffset-bowl2-barrel carburetor is now being used on all 40 series. The WW Stromberg offset-bow1 2-barrel carburetor will also be used in production starting the first week in September.
ROCHESTER CARBURETOR MANUAL CORRECTION
On page 26 of the Rochester Carburetor Manual, Frame 75 should be changed to show the clearance below the stop pin and stator crank operating lever as shown in Figure 21.
We suggest that a note be placed on this frame indicating that a correction was made.
FUEL PUMP FAILURE REPORTS
In B.P.S. 2.387 dated April 22, 1955, we published an article on Fuel Pump Failures. Since that publication a number of fuel pumps have been replaced because of defective diaphragms in order to correct oil consumption complaints; however, upon checking them over it was found that they were O.K.
Ruptured fuel pump diaphragms can be checked by disconnecting the vacuum line from the pump to the manifold and checking the windshield wiper operation. This will give a good indication whether the diaphragm is actually ruptured or not. Therefore, before replacing fuel pump because of oil consumption, make sure all other checks for oil consumption have been made and state on the AFA or product report whether replacement of the pump actually corrected the condition.
1953 – 40 SERIES
A few cases of rough idle, bucking, and missing on 41 Series Synchromesh cars have been found to be caused by flash in the cylinder head exhaust crossover passage. See Figure 22.
The presence of such obstruction can result in poor warm-up, due to uneven manifold heat.
In the event that the above mentioned situation exists, it is suggested that the cylinder head be removed, the flash knocked out with a punch and the port thoroughly blown out before reassembly.
STICKING AUXILIARY VALVES
1955 SERIES 50-60-70 CARTER CARBURETOR
A limited number of Carter four-barrel carburetors #2197S installed on 1955 cars built prior to February 8, had a sticking auxiliary valve shaft which prevented the counterweighted valves from returning to a completely closed position after a wide open throttle acceleration had been made.
This difficulty may evidence itself in slow cold starting and rough open throttle accelerations.
In most cases, the auxiliary shaft may be freed by bending it as listed in the following procedure
- Invert carburetor and hold throttle valves in fully open position.
- Insert a punch beyond the secondary throttle, placing it against the bottom center position of the auxiliary shaft. A light blow with a hammer should be sufficient to eliminate binding.
In extreme cases it may be necessary to remove the throttle body from the carburetor, disassemble the auxiliary valves and shaft and file the mating surfaces of the valves and the shaft smooth.
FLEXIBLE GASOLINE FEED LINE
In order to decrease Service Parts Inventory, a new interchangeable Flexible Gasoline Fuel Line has been developed by the Parts Department for field use. This new Flexible Line fits all 1940 thru 1952; 1953-40 series and will replace the presently released Flexible Line and Pipe Assemblies.
This new line includes only the flexible portion of the old line with a special fitting on the front end so that it can be attached to the existing line. Following are the installation instructions:
- Detach present flexible line from feed pipe at rear.
- Cut present flexible fuel line from pipe at front by cutting present pipe close to where flexible line is swaged to pipe. See Figure 23.
This may be done with a tubing cutter or hack saw. If hack saw is used, make sure pipe is cut at right angles and dress cut end with file. On some models it may be necessary to loosen clamp which holds pipe to the breather pipe in order to have sufficient clearance for cutter. Pipe should be cut as close to swaged joint as possible. The new flexible line is slightly longer than the old flexible portion to allow for the cutting operation.
This new line Group 3.158, Part No. 1392173 includes fitting, see Fig. 23, and parts when present stocks are exhausted:
Group 3.158, Parts 1313342 – 1314332 – 1327793 – 1328922 – 1333306 – 1337089 – 1337090 – 1345903 and 1345921.
MANIFOLD LOCKING PLATE CHANGE
There has been a change in the method of locking the bolts on the exhaust manifold. The previous method of locking these bolts was the use of the ”C” shaped plate which locked two bolts at a time. The new method incorporates the use of one locking plate per bolt. The new part will be furnished for service as soon as the old type locking plate stock is exhausted.
To determine if changes made in muffler constructions are effective, our Engineering Department is requesting that the part number and date which is embossed on the outer shell toward the front of muffler be included on all product reports and AFA’s, effecting mufflers. The date embossed on the muffler will consist of the month and year i.e. 2-55 will indicate February, 1955, etc.
NEW CHOKE PISTON
REPRINT OF SPECIAL SERVICE LEITER -DEALER NO. 152
A new type choke piston is available to help alleviate the roll, loading, and stalling encountered immediately upon starting the engine on early 1955 cars equipped with Carter 4-barrel carburetors. A kit, Group 3.782, Part No 1169567, includes the new choke piston, two (2) choke valve screws, one (1) cover gasket, and a new copper plated (Model 2197S) identification tag, and is available at all parts warehouses.
The new choke piston is cadmium plated and can be further identified by the location of the piston pin hole which has been moved 1/32″ farther from the pin end of the piston. See Figure 24.
Carter 4 barrel carburetors, built prior to Dec. 1, 1954, have the old type choke piston, and can be identified by stampings on the brass identification tag.
NOTE: The letter, stamped on the tag, represents the month: i.e. A-January, B-February, C-March, etc., (excluding the letter 1’I”).
The figure, adjacent to the letter, represents the production year: i.e. 4-1954, 5-1955, etc.
- Carter 4 barrel carburetors marked L-4 and earlier, have the old type piston installed.
- Carter 4 barrel carburetors, marked M-4, with punched arrow in tag, have the new type choke piston installed.
- Carter 4 barrel carburetors, marked A-5, B-5, etc. will have a modified choke housing; therefore, the old type piston will again be put into use.
After a new type piston has been installed, be certain to attach the new copper identification tag (furnished with kit) over the original production tag so that anyone making a future check can determine if the carburetor has the proper choke piston.
A vacuum leak, at any of the following locations, could cause rough idle operation even though the new choke piston has been installed:
- Vacuum pump to windshield wipers
- Vacuum lines to windshield washers
- Intake manifold
- Power brake vacuum lines
Flat Rate – Automatic choke – R&R
LOOSE THROTTLE SHAFT LEVER
A few cases of throttle linkage not operating properly have been traced to a loose lower lever on the accelerator equalizer shaft. See Figure 25.
Due to the hardness of the equalizer shaft and lower lever, it is not recommended to attempt welding as temper will be removed from shaft, resulting in equalizer shaft wear and undesirable rattles. Whenever a loose lower lever is found on equalizer shaft, it should be replaced with a new assembly, Group 3.463, Part #1162415. Flat rate time allowance for this operation is 1.2 hr. which includes R&R and adjust throttle and stator control linkage.
1955 ACCELERATOR PEDALS
It has been brought to out attention that some 1955 models may have the wrong accelerator pedal installed on early production jobs.
If a 50-70 accelerator pedal is installed on a 40-60 series car, insufficient clearance will exist between the edge of pedal and floor pan trans hump, making proper adjustment of throttle linkage impossible.
Figure 26 shows the identification between the two types of accelerator pedals.
FUEL PUMP FAILURES
1955 – All Series
It has recently been called to our attention that a certain number of oil consumption complaints have been corrected by replacing the fuel pump. The faulty pumps are passing oil by the booster diaphragm into the engine intake system.
One easy possible check is to remove all spark plugs and inspect to see if any are fouled. Usually, if the above condition prevails, the #2 plug will be fouled while the balance will be all right.
All fuel pumps having defective booster diaphragms should be properly tagged, marked to the attention of V.0.Wirt, and returned with other warranty material.
REAR MUFFLER SUPPORT
The Rear Muffler Support used on the 1954 and 1955 1st job models, which attaches to the Frame Side Rail and Frame Member, are being replaced by the 1955 after- jobs Rear Muffler Support, which attaches only to the Frame Side Rail, when stock on hand is exhausted.
When installing the 1955 after- jobs Muffler Support on a 1954 or 1955 1st-job car, it will be necessary to install a Spacer and longer attaching bolt to maintain the proper muffler location.
Following are the parts involved:
Group 3.704 – 1162324 – Support- Muffler Rear 1954 40-60-100; 1955 40-60 1st-jobs
To be replaced by:
Group 3.704 – 1168505 – Support -Muffler Rear 1955 40 60 after- jobs
Group 3.704 – 1162281 – Support-Muffler Rear 1954 50-70; 1955 50-70 1st-jobs
To be replaced by:
Group 3.704 – 1168507 – Support-Muffler Rear 1955 50-70 after jobs
When using 1168505 and 1168507 on 1954 and 1955 1st- jobs, it will be necessary to install Group 3.704-1168510 Muffler Support Frame Spacer and a 5/16-18 x 1-5/8″ hex. hd. bolt.
CHOKE SETTINGS ON CARTER CARBURETOR
1955 Series 60-50 – 70
For best warm-up operation the automatic choke should be set at index on all Carter 2197S carburetors (four-barrel) with tags dated A-5, B-5, C-5 and later. The same is true with carburetors built earlier, dated L -4, M-4, etc., which have been serviced according to BPS #2.381, covering the installation of a new choke piston.
Indexing the choke lean will probably cause the Dynaflow equipped cars to “shudder” during accelerations made in early warm-up.