carbking

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Everything posted by carbking

  1. 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.
  2. 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.
  3. I have never seen ANY documentation on the Cadillac/Johnson carburetors from Johnson. There is some documentation on repair in the Dykes Encyclopedia, as well as the Radco repair manuals. We do custom make rebuilding kits for these; however to add to Ed's comments: The most expensive component to the rebuilding of the Cadillac/Johnson carburetors is the automatic, underhood halon fire estinguishing system. Remember, these things come from the same company that thought the way to preheat fuel (other companies used water jacketed or exhaust jacketed carburetors) was to run an electrical current to a heater in the carburetor bowls! Jon
  4. http://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak Jon
  5. For online help, the Ames Performance forums previously mentioned are great; however you will have to ask about 389's as 104 percent of the forum members have 455's . Can't say anything good about POCI, so will say nothing more. Much of the interchange information you requested may be found in the book "Pontiac Muslecar Performance 1955-1979 by Pete McCarthy". This is a paperback book, and not expensive. Excellent resource for Pontiac folks. Another really good book on Pontiac V-8 engines is "How to Build Max Performance Pontiac V-8's" by Jim Hand. While paperback, the book is out of print, and has become somewhat of a cult classic (read expensive!). Another resource would be any original Pontiac factory literature, particularly the shop manual. The Pontiac folks wrote very useful manuals. Jon.
  6. 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.
  7. I have now more than 1000 pieces of original literature on my website, with the majority being carburetor related from about 1909 to 1974. http://www.thecarburetorshop.com/Carbshop_lit.htm If there is carburetor literature you would like to see that you don't see, please let me know. What is there is the proverbial tip of the iceberg. Jon.
  8. 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.
  9. 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.
  10. OK - Holley used a fluid called Stoddard Solvent, which has the exact same specific gravity as gasoline. Jon.
  11. 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.
  12. Difficult to be certain from the picture, but the downdraft carburetor appears to be a Rochester type B, introduced in 1950. Jon.
  13. 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
  14. 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.
  15. Pictures in my "virtual carburetor museum": Hygrade carburetor and fuel pump repair and test station Jon.
  16. 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.
  17. I have no first hand experience, other than personally never needing to do so, thus - no comment. Jon
  18. Dynaflash - if you stop for gas (or any time you restart the engine when the engine is hot), run the engine at a fast idle (1500~1800 RPM) for 30~45 seconds BEFORE you put it in gear. You are experiencing "hot soak". Once you clear the fumes in the air cleaner, and the puddles in the intake manifold, the engine should run as it did before you shut it off. Jon.
  19. If you are truly concerned about the long time damage: These are NOT rare carburetors, as the Riv used the same carb as other 455's (7043240). Pick up one (or more), rebuild it/them (I happen to know of an excellent source for ethanol-friendly rebuild kits ), and put them on the shelf for the future. Change the soft fuel hose(s) every five years. Drive and enjoy the vehicle. Jon.
  20. Ethanol and higher octane BOTH matter, to a certain extent. Ethanol has less energy than gasoline, so might require carburetor recalibration. It DOES effect non-leather accelerator pumps, as well as soft fuel lines in vehicles not frequently driven. Over a long time (25~30 years or so), it can cause damage to aluminum or zinc alloy carburetor bodies. Repeat, this is a LONG-TERM effect. Too high octane fuel will not completely burn in an engine designed for lower octane, without timing and possibly (depending on the compression ration) compression changes. So, if your engine is not specifically designed for the higher octane; you get worse performance, lower fuel economy, and pay more at the pump for the privilege of lowering your performance! Jon.
  21. Additional information: The gasket posted by KongaMan is for a square-bore, but the heat channel in this gasket is the same heat channel used by Buick on the 1967 430. Note the difference in the heat channel in this gasket versus the pictured Corvette gasket. The gasket itself, obviously, is different. Jon.
  22. Additional information by the OP would have been useful, but since not present, will "scattergun" this post: Four different "original" Rochester quadrajet (Q-Jet) carburetors might be found today on a 1967 430 Buick: 7027240 (early production - Federal cars) 7027241 (California cars) (all you folks that believe the "odd last number = standard transmission" - take note of this number) 7027248 (late production - Federal cars) 7041305 (service replacement carburetor produced first in 1971) ALL of these carbs were specified to use flange gasket 1378509. 1378509 was a thin metal plate with asbestos fibers affixed to the plate. The heat channel looks like the gasket pictured by KongaMan, but the interior of the gasket is completely open, there is no division between the various ports. Because of the asbestos, new gaskets will NOT be of the same construction. One might find a new old stock gasket, or maybe not. I mention the various carburetor numbers one would EXPECT to find because of customers (or potential customers) calling us for rebuilding kits, AN AVERAGE OF 65 PERCENT HAVE A NON-ORIGINAL CARBURETOR! As an aside, this is the major reason we do NOT sell rebuilding kits by application only. If a non-original carburetor is present, then the gasket to the carburetor SHOULD be the exact gasket specified by the manufactured for THAT carburetor. Rochester did not specify the part number for the heat baffle, and I don't have a Buick parts book, so cannot post that number. There are a very few heat baffles being reproduced. One needs to KNOW what the original looks like when purchasing these, as they are often over-sold by unscrupulous vendors. Carter did specify part numbers for these, and there are almost 200 DIFFERENT for Carter carburetors. And without totally beating the dead horse, research would be much easier if more information were presented. Jon
  23. As far as the carburetor is concerned: Find the gauge, and set the carburetor to standard setting; then, and only then, you have a repeatable baseline. Until then, you are guessing! The white tailpipe that was once a sign of a well-tuned engine...............................was lead residue! The tailpipes on my OT newer factory fi vehicles are brown/black in color. Fuel economy is definitely NOT all carburetor. Here is an article I did a few years ago: http://www.thecarburetorshop.com/Troubleshooting.htm#Fueleconomy Others may chime in as to what one should expect for fuel economy on a 1939 LaSalle Jon.
  24. My first thought is to test the ignition switch. It may be making contact in the "start" position, but not in the "run" position. Jon
  25. NOT cold starts? There is no heat when the engine is cold Not going to help starting. The ports are there for driveability in cold weather or cool humid weather. And as far as plugging the holes in the intake are concerned: I KNOW we are talking about Buicks on a Buick forum, but folks get here by using "search" as well as just reading the forum. Lots of folks think of blocking the entire crossover, not just the holes. Some gasket manufacturers actually supply intake manifold gasket to block the entire crossover. So just wanting to nail this down to a specific point. Block the holes under the carburetor, but don't even consider the possibility of thinking about blocking the crossover UNLESS you have a trailered racecar (good for about 1 1/2 percent increase in power at WOT). Since I rebuilt my first carburetor on my own car in 1959, I have made two MAJOR mistakes on my own automobiles: the first was thinking I was smart enough to get some decent HP out of a Pontiac 301 by using a turbo, the second was listening to the internet, and blocking the crossover on a Pontiac 350. At my age, even with a manual transmission, the car simply was not driveable for the first 20 minutes or so after starting around town (my "heel and toe" skills have deteriorated ). I finally solved the problem with a carburetor with manual choke. Oh, and the Pontiac 301? Turns out it wasn't low power. The power and torque are good from 2800 RPM to 2900 RPM. What is needed is a 28 speed transmission to keep the engine in its torque curve! Know this post was verbose; but I felt it necessary to emphasize to block the holes under the carb, but not the crossover. Jon