carbking

"Should the inlet needle and seat in a Carter BB carburetor be spring loaded ? " - Maybe "The carb is a DTE2." - Not originally in this specific BBR carburetor. Carter made lots of different fuel valves (well over 1000). Since the BBR is not one of my favorite Carters, have not studied the differences in the various models as I have some of Carter's better offerings. But the specified (original) fuel valve for the DTE2 was 25-102s which was brass seat with Monel steel needle. Once neopreme needles came out, the Monel steel needle was superseded by the neopreme needle. Some previous owner probably installed the spring-loaded valve as an attempt to stop the carburetor from flooding, a common problem on these models due to warpage. Probably more important than spring-loaded versus neopreme tipped is the fuel seat orifice. The cheap kits often have the wrong fuel orifice, which also can contribute to flooding. Jon.

The obvious solution is to start the car everyday As to the Holley being easier to rebuild than other 4-barrels (Frank's comment)??? Familiarization makes anything easier. I personally would rather do a boat load of Carters than 1 Holley; wonder how Cliff would vote on ease of the Holley vs a Q-Jet? Jon.

No comment about the pricing, I don't know. Comments about the car (RED FLAGS): Aluminum heads SCREAM premium fuel, or race fuel (read $$$$$). Headers SCREAM periodic maintenance (read $$$$$), PLUS do you really not wish to talk to whomever is sitting beside you when the engine is running? Scatter shield on a 350 SCREAMS I'm gonna race the crap out of this thing, and I want to save my legs when I over rev the engine. How hard has it been run? What type of warranty? No mention of the camshaft used. The aftermarket carb may/may not be the correct size for the engine. Many folks buy aftermarket carburetors the way a hillbilly buys shoes (the salesman said my size was 9, but 10's felt so good, I bought 11's). (in other words, often too big); which combined with a big cam aluminum heads, a 3.31 rear gear, and headers MIGHT mean driveability issues in town. And as a couple of folks have already mentioned, how much homework did the builder do to assure all of these parts would function well together. You stated this would your first "classic" car. Won't argue the adjective, but will substitute muscle car. Would highly suggest a car with fewer modifications for a first muscle car. Jon

Good question: Older automatic transmissions have considerable power loss through the fluid coupling. I am told by automatic transmission specialists that this is not true for modern (last few years) automatics. The power loss requires gasoline. While there is some power loss in standard transmissions, it is much less than with older automatics. Typically, a carburetor designed to be used on an engine with an automatic transmission will be calibrated from 1/2 to 2/3 of a calibration size RICHER than a carburetor designed for the exact same engine with a standard transmission. Thus, carburetors designed for engines with automatic transmissions MAY be used, with a small loss of fuel economy, on engines with standard transmissions. But carburetors designed for engines with standard transmissions WILL BE LEAN if used on the same engine and an automatic transmission. Also, it should explain why, given the same driving habits; one will always acquire better fuel economy with a manual transmission. Occasionally, linkage arms will be different as well. Jon.

Before you subject the carburetor to the smelly stuff, remove it, turn it upside down to drain any gasoline, place it in a zip-lock back, and place it in your freezer overnight. Sometimes, the expansion/contraction rates of different metals will allow a tiny amount of movement. If you can get any movement, then try the stinky stuff. I don't know current values, but the 144/170 CID carbs used to resemble gold, thanks to the dudes restoring Rancheros and Econolines; plus many of the carbs were trashed long ago, so the supply is short. PATIENCE IS YOUR FRIEND in disassembly of that carburetor. Jon.

Choke not functioning??? Jon.

4-barrel carburetor??? In 1918??? Jon

Paul - I show 115 different Stromberg type U-2, and 68 different Carter type BB-1 in my database. Jon.

Ben - 30 years ago, the youngsters had no clue as to the meaning of vinyl records and turntables; now once again these are quite popular. Now the younger generation knows little about carburetors. Perhaps future generations will tire of EFI, and upgrade to carburetors! It is said that history repeats itself! Jon.

It is this feature that unfortunately, often get beginners to the old car hobby in trouble. For instance, someone may read that a Stromberg SF-4 is an excellent choice for a 1929~1932 Packard to be used for touring. (Opinion - IT CAN BE!). But what isn't written, or possibly written, and ignored, is the fact that Stromberg made hundreds of different type SF-4 carbs for engines from 318 CID to 1503 CID. But there were seven different venturii of different sizes which could be used in the SF-4. Too small a venturi, and the engine will run very well (but poor fuel economy) to a certain RPM, and go no higher. Too large a venturi and the engine will be lean, possibly to the point of damage. This applies to the Carter brass bowl carburetors which are responsible for this thread. While some of the early Carters have the venturi CAST as part of the carburetor casting, most have removable venturii. Without counting, would guess there were more than a dozen. As with any part of an older vehicle, the more one knows about the vehicle, the more enjoyable one's experience with the vehicle. Jon

Ed - I don't know, but I would guess it had to do with proximity. (Both were located in Detroit). When Cadillac discontinued the Johnsons, they used another Detroit company (Detroit Lubricator). Communications and transportation were better than a waxes string with beer cans at both ends, and pack mules; but how much better? Why did Buick stick with Marvel for so many years (both located in Flint)? By keeping one's sources close to home, one could minimize both travel time and costs. Jon.

A bit more information on "chicken/egg": In this age of instant, well generally instant, information, etc., it is important to remember time frames were not always so short. Just looking at part of the Carter prototype file this morning, and noticed some date information. The first issue of the Carter prototype 2507s AFB for the 1957 Buick was completed 21 December 1955. The same day, Carter finished the initial prototype WCFB's for dual quad 1957 Pontiacs. Assigned numbers were 2508s, 2509s, 2510s, and 2511s. There are four numbers because of carburetors for front/rear for both A/T and S/T transmissions. The 2507s (Buick) eventually made production status, while Pontiac decided to discontinue the dual quad option after the 1956 year (Rochesters), and offer the tripower option. Thus, only the 6 sets (12 since there were 2 different sets) of prototype carbs were produced for the Pontiacs. The point being there was a significant lag from request to fruition of a finished unit. Jon.

I think maybe it was the rooster! Of all of the original carburetor documents I have acquired over the years, I was never interested in, nor attempted to acquire, correspondence. So, guessing: The carburetor companies, as new technology developed, would produce a "standard" carburetor. And while I know 31Plymouth asked about the Carter DRT-08, I am going to answer the question with much later Carter carburetors, the AFB 4-barrel. The AFB debuted in 1957. Carter produced standard carburetors in sizes of (approximate) 400, 500, and 625 CFM. The car companies would then contact Carter with a specific requirement as to the size for a given engine, and calibration information. Carter engineers would then work up an experimental carburetor of the correct size, with the throttle hook-ups, fuel inlet, and approximate calibration. This carburetor would be given an "X" number (for experimental). Testing would ensue by Carter, and when Carter was satisfied with the results, a small quantity (in the case of Carter, generally 6) prototypes would be hand-built, and sent to the car company for further testing. Changes could then be suggested by the car company, and made. Assuming the car company was satisfied with the final prototype, then a production number would be assigned. If the prototype did not satisfy the car company, then the print would be stamped "cancelled". Later in the production run of AFB's (Carter produced 505 different), 625 CFM was found to be insufficient for some larger engines, and 750 CFM units were designed. Pontiac wanted even more, and to comply with NASCAR "single carburetor" regulations, Carter built and AFB which, if sold to the general public, would probably have been advertised as a 900 or 950 (the engineers didn't get to assign this information, marketing was responsible). This AFB flow-tested 939 CFM. And 31Plymouth, I used this example because technology in the 1920's and 1930's was changing daily. Not only were there more than 20 variations of the DRT-08, there were approximately 20 different variations of the brass bowl updraft carburetor! A few I can remember without looking: RX0, RAJX-0, RAKX-0, RT-08, DFT-08, DRT-08, and RAJH-0. By the time the AFB came along, technology had slowed to the point where vastly different technology (such as the spread-bore Rochester Q-Jet) only occurred maybe once in a decade. Minor changes would simply be infused to current models. The various brass bowl updraft carburetors had a production run on about 15 years, with only a couple having a run of 3 or 4 years. Contrast that to the AFB with a production run of about 30 years. Stromberg operated basically the same way, although their experimental carbs were assigned "F" numbers. Stromberg production differed from Carter in that Stromberg would produce F-numbered carbs, and would only assign a production (A-number) after a certain number had been produced. I am the caretaker for both the F-number files for Stromberg, and the X-number files for Carter. I do not have the same assortment of documents for other carburetor companies, but guessing the same procedure was more or less followed. Jon.

http://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak Jon

If the results of checking issues Bloo mentioned doesn't help, this link might: Carter Ball & Ball issues Assuming you have the original carburetor, better carburetors were, and are, available. But the originals were cheap! Jon.

Jack - the Rochester model B was introduced to (foisted upon ???) the world in 1950 on 6 cylinder 216 CID and 235 CID Chevrolet. There may or may not be some additional stamped numbers on the throttle body (lower casting) that might date it later. There originally would have been a triangular tag under one of the four screws holding the top casting (air horn) to the center casting (bowl). Should the tag be present, there would be a seven-digit identification number plus a date code. If the tag is gone, so is the ability to narrow it to year. Jon.

It is my thought that some may misunderstand the reason(s) for using a flow bench. The major reason was carburetor design, although racing teams may also use them to test modifications (again, design). The carburetor companies, designing carburetors, were interested in very precise measurements of A/F ratios at specific values of vacuum. A secondary function was the CFM available at different values of vacuum, although many look only at WOT CFM. However, CFM figures, at best, are ambiguous. Anyone that believes a carburetor rated 500 CFM will actually flow 500 CFM still believes in the tooth fairy! The engineers did NOT do thousands of tests to determine an exact venturi size and associated air horn and throttle sizes to obtain an exact CFM figure; rather they used standard diameters, measured the CFM, and submitted the results to marketing. Then marketing would assign a CFM value to the carburetor, depending on the needs of the company in the marketing line-up. For years, I have contended the world's foremost expert on CFM was Mark Twain I am unaware of anyone making the statement before Mr. Twain, but he stated "figures don't lie, but liars figure!". Anyone interested in CFM numbers might enjoy this section from my website: CFM ratings What I know of SOME of the carburetor mass rebuilders is that they had very little interest in warranty/returns. They had agreements with their distributors that a certain percentage of sales were going to be returns, and the distributors "ate" those issues. The units were not returned to the company. Trying to "prove" each unit, would be expensive, raising their "rebuilt" prices above new prices. Basically, the flow bench is more of a laboratory tool for design, than a practical service tool. Jon.

OK - Holley used a fluid called Stoddard Solvent, which has the exact same specific gravity as gasoline. Jon.

While I have never used 3D printing, it seems to be a tool to maybe simplify production of a part. BUT The financial successful production of a part depends in a large part on demand. As an example: I have a set of new old stock air valve springs for the Packard (Detroit Lubricator) carburetor used on a decade of Packards up to spring 1929. 40 years ago, I sent the samples to a "Mom n Pop" spring winding company and had 100 sets made to put in the rebuilding kits for those Packard carbs. It took 38 years to go through 100 sets. Now the "Mom and Pop" company has been inherited by the children who now want a 2500 piece minimum. Even if I could still get the 100 minimum, I would not redo these parts at my age. To the OP - I wish you luck; however keep in mind the comments by others about quality. Somewhere the buck must stop. If one does not care about quality, "stuff" can easily be made in a country far away. And there are some who look only at the bottom line. Jon.

Difficult to be certain from the picture, but the downdraft carburetor appears to be a Rochester type B, introduced in 1950. Jon.

The carburetor and fuel pump rebuilding and testing station on my site had testing procedures and tools for service (volume, fuel leaks, vacuum leaks, etc.). The carburetor companies testing with the wet flow bench did NOT use fuel (dangerous). There is another non-flamable material (no, I do not remember its name) with properties (other than the ability to burn) simiilar to gasoline that is used with the wet flow bench. I have custody of the Carter Carburetor Company flow test files. Lots of folks consider "flow testing" as to determine the CFM of the carburetor; but for the most part, Carter was interested in the volume of liquid and air used at a specific vacuum point from which an air/fuel mixture could be determined. Jon

Are you located in Canada finding 94 octane? Remember, the octane ratings scales used in Canada differ from those in the USA. The posted Canadian rating for the exact same fuel will be several points higher than the posted US rating. Jon.

Pictures in my "virtual carburetor museum": Hygrade carburetor and fuel pump repair and test station Jon.

The pressure build-up is due to expansion of fuel in the fuel line between the regulator and the carburetor. I have been suggesting the use of the return line for 30 years. I didn't invent the idea, just looked at what the manufacturers did 50 plus years ago on vehicles with big engines and air conditioning. The factory engineers were not dummies. Often a good idea to see how they solved a problem, and see if their solution may be migrated to a similar problem. Jon.

I have no first hand experience, other than personally never needing to do so, thus - no comment. Jon