carbking
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Posts posted by carbking
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Tim - thanks for the reference.
Al - we still offer kits (we also offer advice).
The CG should have the two-barrel DD-3 (one of the "2"'s is hidden under the vent).
Before I offer the advice, please remember that we no longer restore carbs, so NOT "grinding my own ax".
This carburetor requires several special tools just to disassemble the carb and not break it.
So the advice is: unless you are an experienced carburetor technician, AND have access to a good machine shop (lathes and milling machines), this carb is best left to a professional. And pick the professional carefully. Very few will have done one of these, and can easily turn an expensive restoration into a very expensive restoration. Don't be afraid to ask questions of the professional.
Maybe the gentleman whose username on this forum is edinmass will see this thread. He would be a good candidate to do the work.
If you wish, call, and we can discuss it further.
Jon.
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I completely understand wishing to keep it original.
I would not have suggested the manual conversion except your original post was about changing carbs for better fuel economy.
And the work scared me as well, which is why I didn't do it! Went to the local transmission shop, and asked what I needed. Got a laundry list, and went to a salvage yard. I bought all the parts at the salvage yard, bought new clutch, pressure plate, and throw-out bearing at the FLAPS, and took everything to the transmission shop, along with the truck. Went back two days later, and drove home the truck.
Shop accepted the used C-6 in full payment for the labor.
Jon.
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And, while many do not like them, a less expensive method of improving fuel economy is to swap in a 4-speed manual transmission. Of course, mileage will vary with your driving habits. Not a Chevrolet, but my 390 went from 17->22 when the C-6 was replaced with a 4-speed manual (highway mileage).
Does require a different set of pedals, and some additional linkage, but these can often be found in a salvage yard.
Jon.
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Sometimes this happens.
Many of the parts will interchange:
Pump piston, "top hat", both check valves.
Power piston plug
Float
Possibly interchange
Power jet pushrod, high speed bleed, both idle tubes, choke and throttle valves
Jon.
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Tinindian - glad you posted the pictures. I have one somewhere, but couldn't find it to picture.
OP - for 1929, it is NOT an air cleaner; rather a flame arrestor. Basically it looks like half of a metal brassiere with a couple of metal straps to hold it in front of the air intake.
And the other one pictured does a good job of filtering small birds and large grasshoppers. Dust and dirt are a different story. Some of these came with no filtering media, with louvers that swirled the air to throw the dirt to the inside edge of the unit, and hole in the bottom for the dirt to drop out. Later they were filled with horsehair which one was supposed to wash in gasoline weekly and then lightly oil. Still later the horsehair was replaced with a course expanded metal similar to steel wool which was also to be washed and oiled weekly.
Jon.
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Before I offer what might be behind the thinking of the shop:
Seemingly in a different lifetime, I was young and enjoyed lots of non-USA vehicles, including a 1968 Datsun Fairlady 2000 which was probably the most enjoyable car to drive I have ever owned; so the following is NOT meant to be derogatory to your Z.
Somewhere along the line, I became convinced that buying American would help keep Americans working; and I reluctantly sold the Datsun.
But to possible reasons for the attitude of the shop:
(A) Knowledge/literature. There are many good aftermarket service books available for the Mustang, and while they are no longer available at every garage sale; they are readily available and cheap. Also, lots of mechanics grew up working on Fords and Chevies and there are probably a lot more mechanics with knowledge of the Mustang than of the Z.
(
Tools. The Mustang can be serviced using S.A.E. tools, the Datsun requires metric. If your shop specializes in older American cars, then no need to duplicate all of your service tools in metric. The same can be said in reverse for shops that specialize in imports.© Parts availability. One can probably completely build a 1967 Mustang if one has a title and a bare spot in one's garage. The same is NOT true for a 1978 Mustang (or most American vehicles made from about 1975~1990, let alone imports such as your Z). There are some parts for my 1996 Ford shop truck that are simply not available new. And never will be again, as demand is insufficient for specialty companies to reproduce the parts.
If the shop owner "threw verbal rocks" at your Z, then that would be unfortunate; but I can certainly understand a shop specializing in older American cars (classic or not) not wishing to work on it. And it is quite possible the first mechanic that said they would work on it was new, didn't know shop policy, and did not wish to turn away a customer.
Jon.
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RT - in this case make it Monday afternoon.
One of the nice
things about growing older is one makes more regular trips to the doctor to prevent making a trip to the doctor. Jon.
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Very carefully, push out part number 20 in the diagram. Now you will be able to separate the two castings.
Call me Monday (573-392-7378 9-4 central), and I will explain how to remove the pump (carpal tunnel).
Jon.
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Another company that made lots of vacuum tanks was Kingston.
Jon.
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Rusty - lots of pixels have been unjustly disturbed about what is the "best" carburetor for racers. I tend to believe any of the major brands (Carter, Holley, or Rochester) can be made to function within a fraction of each other based on the skill and knowledge of the tuner. The TQ does have a very slight advantage with the thermoplastic bowl maintaining a slightly cooler fuel temperature (slightly more oxygen), but only maybe 2 1/2 to 3 percent. As mentioned above, major disadvantage in parts availability today.
But for street, the spread-bore just plain works better than a square-bore for virtually all applications (heavy duty trucks are an exception). As both the Q-Jet and the TQ are spread-bores (Holley and Autolite also made spread-bores) both the Q-Jet and TQ are excellent for the street. As mentioned above, with an inventory of more than 150,000 carbs, I personally chose a TQ for my personal car. (I also have a set of dual genuine Carter AFB's on my shop truck).
For those that like the Q-Jet, the book written by Cliff Ruggles is required reading. And there are really good books on the Holley. Unfortunately, I have yet to see a good aftermarket book on any of the Carters. The best information on Carters is found in: factory service manuals, the Carter Master Parts and Service book, and the Carter Competition catalog.
Jon.
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Rusty - it was 1969 instead of 1968, but what is one year?
Bottom line: We have a few more than 150,000 carburetors in inventory, and there is a Thermoquad on my personal GTO!
The story:
The Carter thermoquad or TQ was introduced as a racing carburetor in 1969. The first production had press-in jets to make changing of jets easy; and it turned out to be much more difficult that normal screw-in jets. Approximately 10 weeks into the production, the press-in jets were changed to screw-in.
For 1969 and 1970, the TQ was sold only as over-the-counter for high performance/racing applications. But in 1971 Chrysler decided to use it on the high performance 340's.
In 1972, the mixture control of the TQ was redesigned to give more control over smog emissions at lower RPMs.
The 1972's were designed with an O-ring seal in the bottom of the bowl. Carter found that the O-ring, which worked well in the laboratory, failed miserably on the street; so the O-rings were replaced in mid-1972 by X-ring seals.
The O-rings are one of two items which have caused the TQ to have a bad reputation, although in my opinion, TOTALLY UNDESERVED!
So why are the O-rings bad, when they were replaced after only a few months? Easy. O-rings in manufacturer's quantities are about 90 cents per thousand. X-rings, in the same quantity are about $2.00 each!!! Guess what the enthusiast gets if the enthusiast goes to the auto parts house and buy a cheap kit, because "the dealer's prices are ridiculous!"? The cheap parts house kit O-rings will fail after a couple of months, and the enthusiast bad mouths the TQ!
The second issue which has plagued the TQ is "split or warped" plastic bowls.
The first time the enthusiast goes to rebuild his/her TQ, he/she removes the 8 screws around the perimeter of the carburetor and shakes the carburetor to get it apart (and it doesn't come apart). Now the enthusiast pulls out the plastic hammer and taps the throttle body, again trying to separate the body castings, but they are "stuck" together. Now the enthusiast pulls out that most destructive of all tools, the screwdriver, and starts prying the castings apart; AND THE PLASTIC BOWL SPLITS!
Now thoroughly disgusted, the enthusiast goes to the parts house to get a replacement bowl (they are not cheap!), and the dude at the parts house shows the enthusiast the two "hidden" screws that reside under the choke plate that the enthusiast didn't see and didn't read the instructions.
And later, a friend asks "How do you like your thermoquad". Answer - "It runs great, but the bowl warped on mine". Anybody that thinks this dude is going to own his/her mistake doesn't know human nature!
And so, the TQ, in the opinion of a few that understand them, is one of, if not the finest of all street carburetors; and to those who simply parrot what they have heard, it is a "piece of ....".
The biggest current problem with the TQ is many parts are available only mail-order from that grumpy old hill-billy in Missouri
Like I stated earlier, I have one on my personal performance GTO.
Oh, and Ford used several on performance EXPORT applications.
And here is a reference link to a satisfied racer:
http://www.dapa.org/drag-racing-with-jim-hand-part-16-a-q-jet-alternative/
Jon.
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The AFB's were pretty well suited to the stock engine.
I believe better sources would be the original Carter specification sheets, and the original MoPar service manuals.
I have had a lot more AFB's come into the shop that were "tuned DOWN" rather than "tuned up".
Unless you have seriously modified the engine, build the carb stock if you can buy gasoline. If you have to use E-10, a couple of minor tweaks may be in order, but build the carb stock first so you have a repeatable baseline. Then you know what your tweaks actually do (or don't).
If you REALLY want more performance, change the manifold, and put a Carter TQ on the engine (DON'T do it with a manifold adapter).
Jon.
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The large secondaries are often misunderstood.
The Q-jet is truly a variable CFM carburetor. Basically built in 3 sizes (although there were some smaller smog sizes in the 80's). The three common sizes:
(A) 750 CFM (most pre-1975)
(
800 CFM (most 1976 and newer, plus some 1971 and newer Buicks, and SD Pontiacs)© 850 CFM (the single booster performance 1971 Pontiacs)
But these figures have to be qualified.
(A) 750 CFM is actually 150 fixed, with an additional 600 variable.
(
800 CFM is actually 200 fixed, with an additional 600 variable.© 850 CFM is actually 250 fixed, with an additional 600 variable.
The amount of CFM on the primary side is dependent on the opening of the throttle plates.
The amount of CFM on the secondary side is dependent on the opening of the airvalve EVEN IF THE SECONDARY PLATES ARE FULLY OPEN.
As the secondary metering rods are connected to the airvalve, the amount of fuel passing through the secondary side is dependent on the airvalve rather than the throttle plates. Long story condensed is that the Q-Jet is only going to open the airvalve for the amount necessary determined by the needs of the engine (assuming the airvalve spring is not fatigued and correctly adjusted), even though the operator has his/her foot on the floor and the throttle plates are wide-open. VERY efficient design.
Of course, if the airvalve spring is fatigued, or badly out of adjustment, or the choke pull off is defective; the carburetor is not going to operate at its potential, but that is the operator's fault, not the carburetor's fault. I have yet to see a self-diagnosing and correcting carburetor of any brand.
And Joe is correct on the well-plugs (although a very few of the early production 1968's still had the pressed-in design). The later spun plugs are much more reliable.
Interesting (at least to me) that Carter and Rochester shared design information on the Q-Jet and TQ rather than the typical "lawyering". The Q-Jet came first, and Carter built lots of them for GM under GM license. Carter found that the 150 CFM primary side was too small for the larger V-8's and marginal for the smaller V-8's, and made the TQ's 200 and 250 CFM on the primary side. Rochester incorportated the 200 CFM primary about 1976. Carter also tried the single booster for higher output (Carter made a 1000 CFM) in 1969; and Rochester used it on the performance 1971 Pontiacs.
Like I posted earlier, unless your Q-Jet is completely worn-out, I would suggest rebuilding it yourself. If it is totally worn-out, then I would suggest having a professional rebuild it.
Jon.
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VERY difficult to beat a quadrajet for fuel economy. The Carter TQ will, but only by a few percent.
Assuming that your Q-jet is not totally worn out, I would suggest rebuilding it.
Jon.
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Thank you.
There should have been a couple of extra wrapped with the fuel valve in the kit.
If you should need additional, NAPA stores (at least around here) have a fiber washer assortment. You can use thinner or thicker, or even stack two or three together to get a thicker total.
Jon.
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Just for future reference:
When adjusting the float for any reason on these older carbs with a cast brass float arm, try changing the thickness of the gasket beneath the fuel valve seat.
If changing the gasket thickness does not work, remove the arm from the float, and HEAT it in an oven before attempting to bend. After heating, bend no more than a couple of thousanths of an inch and allow to cool. Repeat as necessary. Patience is your friend.
Jon.
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Was going through some stuff the other day, and found some of the items pictured below. As there seem to be many on this forum interested in the Marvel carburetors, I thought I would share.
Even tho Marvel doesn't rank very high in my list of carburetors, I have to admit that Marvel DID have a lot of help/parts for the car dealer to at least TRY to make the Marvels work.
The first item is the glovebox booklet. Marvel printed dozens of different of these for the various applications. They occasionally surface on Ebay, but one could look a long time before one found the booklet for their individual application:
http://www.thecarburetorshop.com/Marvel_glovebox.jpg
The next item is the Marvel Master parts and service manual. These were printed at different times, with the first printing covering roughly 1916 through 1925 or so; and then each year an updated manual would have been printed, dropping some of the earlier applications. I have sheets in mine up through 1938. My book, covering 1916 through 1938 is 8 1/2 by 11 by about 1 inch. These rarely surface, but do maybe once every 3 or 4 years:
http://www.thecarburetorshop.com/Marvel_book_1.jpg
The next item is the Marvel Bulletins book. This book is about 8 by 10 by about 3 inches, and contains "factory fixes" to attempt to make the carburetors function. I find it interesting that the "fixes" book is about 3 times the size of the main book. Carter, Stromberg, and Zenith also published bulletin books; but their bulletin books are maybe 1/4 the size of the main books. Give Marvel credit for trying! I have seen exactly two of these books since I started looking in 1965. Pretty difficult to find.
http://www.thecarburetorshop.com/Marvel_book_2.jpg
The next item is the dealer cabinet, which contained "fast moving" Marvel parts for the car brand sold by a car dealer. They surface every other year or so, but generally devoid of parts:
http://www.thecarburetorshop.com/Marvel_cabinet_1.jpg
The next item is the jobber cabinet, which contained a much larger selection of parts. There are at least a couple of different of these. I have seen 4 or 5 since 1965:
http://www.thecarburetorshop.com/Marvel_cabinet_2.jpg
And the last item is a factory Marvel tool kit, with specialized tools to work on Marvel carburetors. Comparing this tool kit to those of other carburetor manufacturers suggests there is probably a missing tray (note there are supports which probably supported a tray). As this is the only one I have ever seen or even heard of, I cannot verify my guess:
http://www.thecarburetorshop.com/Marvel_tool_1.jpg
http://www.thecarburetorshop.com/Marvel_tool_2.jpg
There were some earlier books printed prior to 1916, but they are fragile, and I did not picture them.
Jon.
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Most enlightening, thanks for going to the trouble of sharing this information; mind if I copy it to a newsletter down here ?
No problem, feel free to quote anything I post which you feel is worthy of quoting, and thank you for the complement.
Jon.
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Jim - see new BB-1 thread under "General Discussion" forum.
Jon.
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There seems to be much mis-understanding of this really good carburetor and its applications.
The BB-1 carburetor SERIES was designed and tested in 1930 and 1931 by Carter, and released for production in the fall of 1931 for use on 1932 Plymouth, DeSoto, and Chrysler automobiles. At this time, the BB-1 was really leading edge technology. As a side note, the fall of 1931 was a really good time for carburetors, as the Stromberg SF SERIES was released for production at the same time.
Mechanics of the day were quick to realize the quality of the BB-1 and began substituting these units for use on older vehicles with older technology carburetors.
As the above was brought to the attention of Carter, Carter immediately tested and released three different universal model BB-1 carburetors which were much better suited for replacement use than the O.E. units mentioned above.
These three replacement units were:
S.A.E. size 1 - Carter 245s
S.A.E. size 2 - Carter BB-1A
S.A.E. size 3 - Carter 289s
S.A.E. size 4 - Carter 263s (prototypes, testing, but NO PRODUCTION)
The universal carbs featured: (A) "universal" throttle shafts that extended through the casting on both sides to facilitate fastening the clamp-type throttle arm on either side, (
adjustable main metering jet to aid in calibration without having to buy several different sizes of main metering jet, © a "fast idle" provision, which amounted to a flat rod connecting the choke and throttle which would slightly open the throttle for additional RPM when the choke was engaged, (D) different (richer) idle jets and main air bleeds to facilitate the use on different sized engines.The pre-WWII castings were both cast iron.
History kind of intervened or the Carter BB-1 might have been used on lots of different cars; but the mechanical fuel pump was becoming more common, thus the proliferation of downdraft rather than updraft carburetors. So the only original automobile applications for the Carter BB-1 were the aforementioned 1932 Plymouth, DeSoto, and Chrysler units.
However, the Carter BB-1 still had uses. Cab-over-engine (COE) trucks continued to use updraft carburetors, as did marine applications due to the reduced engine height required. So the Carter BB-1 in all three physical and several different internal sizes was used on truck and marine applications well into the 1960's. The most common applications were Chevrolet and Dodge trucks, and Gray and Owens marine. There were also some military and industrial applications. In all, there were 69 different carburetors released in the BB-1 series.
Note that the "service" requirements for truck and marine applications is quite different than for automobile. These engines are basically asked to idle, and to run at some constant higher RPM, thus the internal calibration of carburetors for these units often does not have the same circuitry for part throttle and changing RPM as is required for smooth operations in an automobile.
The BB-1 castings were redesigned after WWII, with a zinc alloy replacing cast iron for the lower (bowl) casting. As the zinc alloy will warp without fastenings which are much closer together (reference the Rochester B series carbs), Carter changed both castings to have 6 bolt-to-throttle body screws rather than the three used with both castings being iron. The universal carbs were then renumbered as follows:
S.A.E. size 1 - 245s -> 245sd
S.A.E. size 2 - BB-1A -> BB-1D
S.A.E. size 3 - 289s -> 289sd
The Carter BB-1 does have several "issues", all of which are easy to address by a competant rebuilder:
(1) During periods of long disuse, the brass accelerator pump will stick to the lower body, often making disassembly difficult. The use of an ultrasonic cleaner, virtually always will free the stuck pump, and allow disassembly.
(2) The idle circuit has a "hidden" jet, deep in the lower casting which requires the use of a special screwdriver to remove. The orifice is quite small, and failure to remove the jet, and clean the passageway beneath the jet will generally result in poor idle quality.
(3) The power jet has a replacable spring, which fatigues due to having to support the power jet pushrod. The spring MUST be replaced during rebuilding. Failure to do so will cause the power jet to always be open, resulting in an overrich condition throughout the RPM range. The spring comes in the better rebuilding kits, and is easy to replace, but it must be done.
The only complaint I have with the Carter BB-1 series carbs is the mechanical accelerator pump. MOST other updraft carburetors with accelerator pump activate the pump using vacuum rather than the throttle.
So why is this important?
If a novice attempts to start an automobile with an updraft carburetor and pumps the footfeed a dozen times as he/she would do with a downdraft carburetor, the mechanical accelerator pump will pump fuel into the throat of the carb, but since the fuel must travel UP into the intake, the fuel instead runs out the front of air intake onto whatever is below the carburetor (sometimes the exhaust!).
However, if the same novice uses the same procedure with a carburetor with a vacuum activated accelerator pump, he/she merely exercises their ankle! The pump does not function until the engine is started and vacuum is present.
Vehicles with updraft carburetors SHOULD be started using the choke valve.
As to identification, ALL Carter BB-1 carburetors were originally tagged. If the tag is gone, exact identification requires the carb to be disassembled, and the jets and air bleeds compared against the original prints. Due to the popularity of the BB-1 and the universe full of Chevrolet truck carbs versus the very few universals, this creates problems for the user.
If information is necessary on S.A.E. sizes, please refer to this link:
http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm
Jon.
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Jim - other than to state the obvious that the identification is on the tag, there is no easy answer.
If the tag is missing or some unscrupulous individual placed the wrong tag on the carburetor, exact identification REQUIRES disassembly of the carburetor, and comparison of the calibrated internals with the Carter prints.
It is easier to eliminate the carburetor from being a BB-1A or BB-1D than to positively say it is.
The BB-1A has both upper and lower castings which are cast iron.
The BB-1D has a cast iron upper and zinc alloy lower casting.
Both BB-1A and BB-1D have center-to-center mounting bolt spacing of 2 11/16 inches.
Both BB-1A and BB-1D have "universal" throttle shaft (extends on BOTH sides of the carburetor), a fast idle attachment, and an adjustable main metering jet.
However, as the value of the BB-1A and BB-1D is significantly more than the value of the Chevrolet truck 517s (which uses similar castings BUT DIFFERENT INTERNALS), some of the external parts have been reproduced off-shore to make the less expensive carb look like the universals.
Let us hope that you do in fact have either the BB-1A or BB-1D and something else is the issue.
Jon.
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Carter produced 69 different type BB-1 updraft carburetors. Simply saying "BB-1" is similar to saying "15 inch tire".
Of those, ONLY the BB-1A and BB-1D should be used on the Franklin.
Possible idle issues as posted above IF CARBURETOR RELATED would include:
(1) Incorrect BB-1
(2) Too much fuel pressure or incorrect float adjustment
(3) The hidden idle jet was not removed and cleaned by the rebuilder, or the passage has a clog
(4) Incorrect adjustment of the curb idle screw (not the mixture screw)
(5) Incorrect adjustment of the fast idle screw
(6) Hopefully not, but throttle valve installed incorrectly in the carburetor (yes, I have seen this numerous times).
(7) Power jet not rebuilt, thus power jet open at all times.
The BB-1 IS a great design, when properly selected for the application, and properly rebuilt.
And other possibilities other than carb exist, the number one other possibility would be a vacuum leak.
Jon.
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According to the carburetor manufacturers Schebler, Stromberg, and Zenith; carburetors were sold to Apperson, Courier, Henney, Hensey, Parenti, Stephens, Saxon, Velie, and Washington for use on Falls engines.
As the carburetor manufacturer did not always post the make of engine, but only the make of vehicle; there are probably many more.
Jon.
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I don't know how someone could steal a word from Webster's and own it.
I wonder if Webster would publish a dictionary without the trademarked words, so us peons would not get in trouble for using these forbidden words.
Does it give an organization more credibility if the organization feels the necessity to trademark a common word???
Jon.
Tools. The Mustang can be serviced using S.A.E. tools, the Datsun requires metric. If your shop specializes in older American cars, then no need to duplicate all of your service tools in metric. The same can be said in reverse for shops that specialize in imports.
things about growing older is one makes more regular trips to the doctor to prevent making a trip to the doctor. 
1941 Buick dual Stromberg carbs tuning
in Technical
Posted · Edited by carbking (see edit history)
Question 1: smaller jets are available
Question 2: originally, the linkage was progressive
Other information:
Buick started experimenting with compound carburetion as early as 1935 (Stromberg built some experimental single barrel carbs for Buick, it this time they were experimenting with two single-barrel carbs).
The compound carburetion, as offered in production (two 2-barrel carbs, either Stromberg or Carter) never did perform to Buick's expectations. Most were removed in the first couple of years, and in fact Buick discontinued the production after the 1942 models.
Fast forward to today. We have seen many of these setups, and ever single one we have seen have had the following issues:
(1) Heat valves in the exhaust manifold stuck in the closed position, which caused excessive heat to crack the intake manifold creating a vacuum leak
(2) The auxiliary air valve under the rear carb warped in the closed position, so the rear carb would not open.
For customers with showcars, we have (in the past) freed the heat valves, fabricated new heat springs, machined new auxiliary air valves, and had the intake manifolds welded (not me, my welding looks like the underside of the desk I used in third grade
) to fix. And the units still didn't perform as well as a single carb.
For customers with "drivers", we suggested:
(1) Removing the heat valves from the exhaust
(2) Removing the auxiliary air valve
(3) Using two exact matching carburetors from different engines (eg., two of the carbs from the small Buick engine from the late 1940's work great on the large engine).
(4) Rework the linkage so it is solid rather than progressive. This allows BOTH carburetors to operate all of the time.
All of our customers loved the results with the modified system.
Jon.