carbking

They are 625 CFM. Marginally large, but the front carb is not calibrated to run solid. The CFM is close enough on this engine that you might be able to recalibrate these and run solid linkage, especially since they are Carters, with the air valves. I run two HIGHLY MODIFIED 625's on my high performance 390; but I spent a LOT of time on the carbs. Idle tubes, idle bypass, idle air bleed, all jets, step-up rods, step-up springs, all four jets, and the auxiliary air valve were modified. But it runs GREAT! Jon.

According to Autoweek, Harry Miller founded the Miller Carburetor Company in 1909, sold the business in 1912, and founded the Master Carburetor Company in 1913. I have never seen any factory Miller carburetor literature. I do have quite a bit of Master carburetor literature, beginning in 1915, and the last dated one in 1918; so evidently, they were around for awhile. We have sold quite a few conventional throttle carburetors to some pretty good restoration shops that were unable to make a rotary throttle carburetor work except idle and wide open throttle. Jon.

I have added several new exhibits today, and that will conclude the initial exhibits. Others will be added in the future. Today's additions include: Correcting the alcohol pump to alcohol control valve per Joe P.'s suggestion. Thank you Joe. Pictures of the infamous Rochester type AA, and the one year only Rochester BB The 1918 Oldsmobile 2-barrel that some enthusiasts keep calling a 4-barrel Some rotary throttle carbs, including a prototype with gear drive on the throttle The aftermarket Riley and Flynn high performance carburetors. The Detroit Lubricator type 51 Cadillac V-12 carb. The "high mileage" (along with a tooth fairy ) Pogue and Fish carburetors. Jon

Early February 1961 Ford 144 CID 6 cylinder S/T, first design single barrel made by Holley. Carb is too dirty (and my eyes aren't sufficiently strong) to read the Holley number. But if you will take a wire brush, followed by a pencil eraser to the fuel boss in your first picture; then hit it with a strong light at a sharp angle, and look through a STRONG glass with a pair of young eyes, you should be able to read it. Personally, it looks beyond being a core. Jon.

Maybe this will help: http://www.thecarburetorshop.com/Multiplecarburetion.htm Jon

Thanks Joe - so the little double brass tank with the funny looking figure 8 diaphragms that I hand cut, that I have always called a pump, is actually a fluid control valve? On another note, looking for my picture of the AA carb to post, but haven't found it yet. May have to take another. I am not certain if I still have a BB or not. Still a lot of exhibits to add, but can only do so much at one time. Jon.

Greg - I have some of the Masters. Will be adding exhibits as time permits. The initial posting was stuff of which I already had pictures. Thanks, Jon.

Pfeil - from my website: " Fast forward to the mid-1950’s and the horsepower wars, plus the emergence of local dragstrips throughout the country. The racing sanctioning bodies often would allow internal engine modifications (camshaft, compression, etc.) but REQUIRE the use of the original carburetor(s). Thus the car manufacturers would offer twin 4-barrel setups with progressive linkage so that they could use carburetors THAT WERE TOO LARGE FOR NORMAL DRIVING. During normal street use, the engine would run only on the primary carb, and engage the secondary carb only under “spirited” street driving; BUT the larger carbs were present to provide sufficient airflow for engine modifications of larger camshafts, increased compression, etc. Street drivability with progressive linkage will never be as crisp as using solid linkage." The 1956 Pontiac used solid linkage, with idle screws and choke assemblies on both carbs. The carbs were sized to the demand of the engine. I do not know why Pontiac used idle circuits on both the 3433s and 3435s; but the Pontiac SD engineers were pretty sharp dudes! GUESSING the street idle would have been better. I have twin 625's on my 390 shop truck; with solid linkage, idle and chokes on both. Jon.

padgett - if you haven't found it, go the the HAMB and search for: rare pontiac intake There are several pictures in the thread. Jon.

Lincoln did not use Johnson, they used Stromberg, and it was an excellent carburetor, absolutely no need to replace. We have not yet found an updraft that will function in place of the Johnson because of the rainbow manifold, at least on the later cars. At one time we offered a pair of Zenith for the V-12 and V-16 (no rainbow). Personally, I if had a 1925 or earlier, I would at least try to see if one of the Chevy Carter BB-1's would clear. The flange arrangement is different on the 1926 and newer such that an adapter would be required; but the late Chevy BB-1 should bolt to the 1925 and earlier, IF there is sufficient clearance. While I like to keep the old cars stock if possible, I simply cannot recommend using a Johnson on a vehicle that is driven. I would rather have a non-original carburetor than an original molten stack of metal. Some of the zinc ally carburetors (the Stromberg U-2 is one) can be, and has been recast in better metal. Recasting the Johnson would only make for a more expensive Johnson. I am certain that someone of Ed's talents could keep one running, at least for awhile, but I still wouldn't ride with him if he were using a Johnson Jon.

Padgett - it wasn't a two-barrel! The two holes are connected to an 90 degree adapter that then is connected to a Carter type YH sidedraft carb (like the one I pictured for the 1953 Corvette). The carbs would have been Carter AFB's, either the 3443s (750 CFM) or the 3444s (675 CFM). There are some pictures of the complete setup with the adapter and the YH floating around. Google Pontiac bathtub. It should come up somewhere. Jon.

Ed - as time permits, I will add more exhibits; although I don't have a lot for Johnson. Johnson did offer some useful "glove box pamphlets" that gave the driver adjustment information, but doubt seriously that it worked. I have a difficult time getting enthused about a carburetor company that put an electrical resistance heating plate in the carburetor bowl on some models to preheat the fuel! I do have a Fish carburetor to picture, and pictures of the very rare Pogue carburetor. Also have a Kingston two-barrel prototype for the flathead Ford that was never produced. And a bunch of other stuff. The initial exhibits are just from pictures that I already have on my computer. Jon.

Announcing the opening of The Carburetor Shop Virtual Carburetor Museum. Additional exhibits will be added, time permitting.http://www.thecarburetorshop.com/Car...ual_museum.htmJon.

It was spring-dampened. Its function was to increase A/F velocity when the throttle was quickly opened. Think of the "automatic throttle plate" like the auxiliary air valve on a modern Carter AFB secondary. The driver can open the throttles wide open with the footfeed, but the secondary will not open completely until the engine had increased speed to where it could ingest the additional air/fuel. The "automatic throttle plate" works exactly the same way, only opening (assuming correct adjustment) as quickly as the engine can use the air/fuel. The restricted opening keeps the air/fuel stream velocity at the desired level. Air velocity is one of the most important elements in carburetor metering. And I still don't like the carburetor! As far as adjustment: try rotating the adjuster until the automatic throttle plate just touches closed with no tension; then rotate another 1/2 turn (180 degrees) and tighten the lock screw. Jon.

When you get your mesh, first make a good sharp 90 degree bend by bending over the edge of a piece of metal. Then, work that around the end of a piece of pipe to form the curve. As to carb kits in general: 70 years ago, the genuine Carter kits included the screen, as well as the metering rod, the metering rod jet, the idle jet, and some of the linkage. Such a kit today would probably sell for several hundred dollars, but it wouldn't sell. 50 years ago, the FLAPS started complaining about the necessity to stock so many different kits, and the "Jiffy" kit or "clean-out kit" was born. Typically, the kit manufacturers did a spread-sheet of every carburetor using the same pump diameter and approximate length, and every fuel valve with the same physical dimensions (regardless of the orifice size) and then added all of the gaskets, check balls and pin springs that fit all of these carburetors. This would become a clean-out kit. Should you be interested in one of our kits, please call during normal telephone hours. I don't feel this is the place to describe ours. EDIT: got my years wrong. Replace 70 by 85. Replace 50 by 65. Sorry. Jon.

If you bought your kit from us, and if you are willing to spend the $8.10 priority mail (within the 48 states), will send you a screen. I don't know the mesh size, but have a decent inventory of N.O.S. screens. Jon.

Ed - I tried JB Weld once some 40 years ago to fix a carburetor crack. But my policy has always been to test any product unknown to me before using it on a customers carburetor. So after repairing the crack, I put the entire casting in a container of fuel, and sealed it. Three months later, I opened the container to find the JB Weld had softened. But the early pot metal, depending on company, before from about 1931 to 1936, will continue to fail; so even if the epoxy did not soften, the use of the epoxy to fix defective pot metal for the long term is a terrible idea. If the vehicle is a show-car, then spend the money to have new castings cast and machined from some more stable metal. If it is a driver, just change the carburetor to one without built-in failure. Jon

"Can you describe why a solid vs. sequential dual quad carb linkage is superior? " Better average cylinder fill density. "Would this be something easily done to a stock Super Wildcat ('64-'66) car? What is the downside to the stock setup?" NO! Do not try it with the stock carburetors! Possibly it could be done by heavily modifying the stock carburetors. The downside of the stock dual quad is the cylinder fill density on the front cylinders is leaner (except WOT) than the rear cylinders. This will cause a slight imbalance in the engine. What are the percentages? Don't know; but I have been doing solid linkage on customer aftermarket setups for almost 50 years, and, so far (where is the "knock on wood" emoji?) everyone has been happy. There is a noticeable difference in driveability in city driving (less than WOT operation). My shop truck will idle at 600 RPM, and, once the engine is at operating temperature; the throttle may be mashed from idle in first, second, or third gear with zero hesitation. In fourth gear, RPM must be at 1000 or more before mashing the throttle, or the engine will stall. Since the secondaries on both carbs open as needed, one cannot even tell when the secondaries open. When the footfeed is mashed, just raw power from idle to shift point. And the truck gets somewhat better fuel economy at 70 MPH than it did with the single four-barrel (average cylinder fill density). And yes, I am using genuine Carter AFB carbs (that have been "slightly" modified). Jon.

Matt - Jim is absolutely correct about the original Schebler. Jon.

OK, a bit more time this morning to answer than in my first post. I have this mental image of someone trying to start the car by pumping the footfeed 😜 The guy is sitting in the driver's seat, gripping the steering wheel so hard that there is blood on his palms from his fingernails, pulling back on the steering wheel so hard it is warped, and pumping the footfeed as fast as he can move his ankle. The air in front of the gentleman is blue and moving rapidly. The guy's face is about the same color as a fire engine, and the ammeter is pegged (empathetic blood pressure gauge ) OK, what has happened and probably happening. Modern fuel evaporates. I have a similar setup to the OP in my shop truck (dual Carter AFB's) except my linkage is set up solid instead of sequential for much improved performance, both in driveability and fuel economy . Several years ago, I had the same issue, and after the engine had sat long enough that I didn't burn my fingers, I pulled the airhorn from one carb. The bowls were bone dry! The heat from the engine evaporated the fuel that fast (that 390 produces a LOT of heat). That is when I installed the electric fuel pump. I mounted my pump right at the tank to supply the working original fuel pump (which acts as a pressure regulator, so no external regulator is required). I have a push-button switch on the dash. I can manually energize the pump to fill the bowls for starting. Once the bowls are full, release the push button, pull the choke button (I have manual chokes on both carbs), and start the engine. Once I have oil pressure, the permanent wiring on the fuel pump energizes, and the pump runs as long as there is both ignition on, and oil pressure. Removing either ignition or pressure will kill the pump's operation. The above is my solution. When the bowls are dry, the carburetor (obviously) cannot function. When one pumps the footfeed madly, the accelerator pump will begin functioning as soon as there is sufficient fuel in the bowl to cover the pump inlet check valve (screwed into the base of the pump cylinder), BUT THE FUEL LEVEL IN THE BOWL IS TOO LOW FOR EITHER THE IDLE CIRCUIT OR THE MAIN CIRCUIT TO FUNCTION! So fuel is pumped into the engine, SLOWING the ability of the fuel pump to fill the carburetor bowls to a level where the normal circuits can function. And to dispel one myth often suggested: it is quite impossible for MOST (not all) carburetor bowls to drain back to the tank (unless the owner parks the vehicle on its roof ) Most carburetors have the fuel valve HIGHER than the fuel level in the bowl(s), thus fuel cannot flow backward through the fuel valves. The notable exception to this (there are others) is the Rochester Q-jet. However, Rochester did address the issue in two ways: (1) with the internal fuel filter behind the fuel inlet nut getting an internal check valve, and (2) the use of solid fuel valve seats rather than "windowed" fuel valve seats on some models. Also, Q-jets from 1965 to 1967 had the pressed in well plugs, which could leak. Rochester fixed that issue in 1968 with the spun plug. The carburetor that spawned the term "carburetor leaking down" was the Holley model AA-1 (a.k.a. Holley 94). The economiser valve (a.k.a. power valve) was located in the BOTTOM of the bowl, with a direct passage to the intake manifold. The valve had a neopreme component. A carburetor backfire would normally kill the valve, which opened a direct passage to the intake, and the carburetor WOULD "leak down". Over the last 20 years, I have talked hundreds (perhaps thousands) of prospective customers out of buying either a carburetor kit or a rebuilt carburetor for this issue. One just has to learn how to deal with the fuel. And while ethanol deserves a lot of bad-mouthing, this is not an ethanol issue. There are other aromatics in the fuel which have raised the Reid vapor pressure of the fuel over the years. If anything, the ethanol slightly lowers the Reid vapor pressure (ever have the liquid in your Jim Beam glass empty itself by evaporation?). Jon.

Pumping while attempting to start is self-defeating. As mentioned by others, the fuel evaporates out of the bowls. Pumping while attempting to start will give enough fuel to the engine to fire but not stay running, plus the bowls are not being filled. Again, as mentioned by others: (1) Fill bowls with squeeze body or eye-dropper through the vents. OR (2) Crank the engine WITHOUT PUMPING for about 10 seconds, then stop cranking, pump the footfeed three times, and start the engine. OR (3) Electric pump Jon

We have a checklist of questions we ask carburetor customers (or prospective carburetor customers) when they call us. Once, the first question we asked those with idle issues was have you done a compression test. Now, the first question asked those with idle issues is has someone installed an electronic conversion in the distributor. If yes, the second question is do you still have the points and condenser to reinstall, at least for testing purposes. Jon.

I know nothing about the company you mentioned with the rebuilt carburetor, so the following is a general statement: Since the 1950's, the commercial carburetor rebuilders have "grouped" carburetors together to reduce inventory. To accomplish this, holes were drilled to accomodate tubes for various vacuum requirements on the various carburetors grouped, parts often are used from various carburetors in the grouping, and the final calibration is set to be the richest of the carburetors in the group. To give an example: some time ago, had a customer with a 1965 GTO and a commercially rebuilt carb that ran, but not overly well. I had him get a lot of numbers on the carburetor, and was able to determine that he had a 1963 main body, a 1965 top casting, primary clusters from 2 different years (don't remember which), and a calibration for a 421 with automatic and A/C (instead of the 389 with standard transmission). As stated earlier, I know nothing about the company that you mentioned; but the odds are that the carburetor you have is better than the rebuilt carburetor you will buy. The "core" charge probably is not a lot; just makes good sense to keep what you have. Jon.

BEFORE buying a different carburetor: Take the airhorn off of the existing carburetor. Use a paper towel or rag, and remove ALL of the fuel Put the airhorn back on the carburetor. Find a ketchup or mustard squeeze body, empty the food? contents, clean, and fill with FRESH gasoline. With the squeeze body, fill the carburetor through the bowl vent. Now try starting the engine again with starting fuel. I believe it will start, and idle about 10~15 seconds on the fresh gasoline. If it does, drain the tank. And as Bloo stated in the post above, if you must have a different carburetor, KEEP your old one! Jon.

As to the availability of parts: To my knowledge, only three companies offered parts for the brass bowl carburetors back in the day: (1) Carter (obviously) (2) Standard Hygrade (3) Hawk Products Hawk is probably less well-known than the other two. Hawk was located in Indianapolis, and later made carburetor parts for more modern carburetors under the name Sherman. Again, most of the aftermarket stuff was keyed to Chevrolet. Jon.