Ladies and Gents, Looking for some help please in identifying the carbs in the photo attached. The photo was posted in a HAMB bellytank thread, and some Googling shows it is also on Pinterest. I have a pair of identical carbs that I purchased Down Under, which had been used on a historic Holden racer (138ci "grey" I6 motor, with a really funky aftermarket head). Local carb shops could not identify them, so I did a heap of reverse-engineering to get them to work. They appear to be Stromberg variants, but so far I have no leads on identification. Appreciate feedback please on the real iden***y of the carbs. Cheers, and thanks, Harv
Thanks Deuces. I hope so - they are cool carbs, and I would really like to understand them better. Attached below are the notes I took trying to reverse engineering. There were a heap of photos and some scale drawings I made, though these are now lost in PhotoBucket. The history on these sidedraught carburettors has been lost. The seller understood that the carburettors were used on aftermarket Repco heads (Holden "grey" motors, 1948-1963), one in custom road circuit racer, and one in a dragster. The previous owner had the Repco heads stored in a building which burnt down, leaving only the carburettors which had been stored separately. There are no manufacturers markings, stamps or castings on the carburettors. As we will see below, the carburettors seem to take parts from a number of sources, though the photo above from the bellytank thread would suggest otherwise. I checked with Carburettor Service Company in Sydney, and they were of the view that the carburettors were custom cast. Having said that, the castings are very neat, with no obvious occlusions, flash or voids. The main body casting has a yellow dichromate finish. If these are home-cast, they were a very professional job. I’ve checked a number of other period sidedraught carburettors include the Carter YH and Zenith 11ADX12 (and more mentioned in the text below), though again they are very different from these carburettors. If anyone knows the manufacturer of my carburettors, I’d love to hear from you. The mounting flange is a 3-bolt single barrel non-equidistant setup. It is similar to the 2-barrel Stromberg 3-bolt EE-model (“Stromberg 97”) flange, but not the same. Some Harleys ran 3-bolt non-equidistant flanges (for example on the Linkert carbs), though these carbs look nothing like any Harley I’ve been able to Google. The steel manifold studs are ¼-20/28 UNC/UNFx15/32”. Two of the three studs on each carb have been cast into the Repco manifolds, though it looks like this was done afterwards (drill an oversize hole, insert the stud, then pour in liquid aluminium) as the studs are not altogether horizontal, and the casting is porous around the studs. The carburettors have a throttle bore of 1 7/16”, an air horn OD of 2¼” and a venturi diameter of 11/16”. The venturis are changeable, being constructed of an interference fit aluminium sleeve, partially pinned in place by the main discharge jet mitred tip. The throttle plate and shaft are both br***, held together by br*** 6-32UNCx¼” raised countersink head screws. The screws are hollow point to allow them to be staked in place. The throttle shafts are fitted with br*** collars on one side, and br*** idle speed levers on the other. The idle speed levers are held in place with 10-32UNFx9/16” fillister head bolts, relying on the bolts to purchase onto the round throttle shaft. The idle speed levers act on a lug on the throttle body castings, and are adjusted with 10-32UNFx7/16” fillister head bolts, locked in place with a #6-32UNCx9/32” cross-screw. The carburettors have a single float bowl, with the liquid level controlled by a Stromberg EE-type float and screwed hinge pin. The hinge pin drilling has been made all the way through both sides of the casting. One side of the drilling is threaded (to accept the hinge pin threads) whilst the other side has been blinded off by a lead plug. Whilst the floats are Stromberg, Stromberg however only made one type of sidedraught carburettor (the OH model), and this looks nothing like it (the OH for example had a round-shaped float). The needle and seat orifice, located inside the inlet banjo fittings, is 0.104”. This is considerably larger than a standard Holden grey motor (0.070”), and closer to typical Holley (0.110”). The larger diameter needle and seat orifice would support methanol flow for the 138ci grey motor. The outlet of the banjo fittings is sized to -4AN, whilst the inlets are the funky 7/16¬”-24 thread used in Stromberg carburettor fuel inlet threads. The float bowl is 1 11/16” deep, and contains an integral-cast metering block. The float bowl lid, fastened by three 10-32UNFx9/16” round-head bolts, has a single hole drilled through the casting to vent the float bowl. The hole is drilled at 0.070” diameter vertically, and then at 0.078” horizontally. The float bowl lid also has two br*** inserts, probably made by drilling holes and inserting br*** rod. The purpose of the inserts, pictured below, is unknown though the photo from the bellytank thread looks like they are rivets for ID tags. The integral-cast metering block has four vertical p***ages. The first p***age is an air-bleed inlet. Air p***es through a br*** mesh screen pressed into the side of the carburettor. The air flows through the br*** mesh screen and upwards to fill the cavity between the metering block and float bowl lid. Note that the float bowl lid forms two separate compartments – a cavity above the float bowl, and a separate cavity above the metering block. From the metering block cavity, air is able to flow down each of the other three vertical p***ages. The second p***age is the main fuel discharge. An anti-siphon bleed is pressed into the top of the p***age. The bottom of the p***age is press-fitted with a mitred steel main discharge jet, which protrudes from the bottom of the metering block into the carburettor throat. The third p***age is the main metering p***age. The p***age is connected to the fuel bowl by a cross-drilling located some 3/16” above the float bowl floor (shown by the black circle in the image above. The cross-drilling is fitted with a 0.0955” main metering jet. This is a rather large jet, being 3½ times the area of a typical Holden grey motor Stromberg jet. This again points to the carburettors being set up for methanol. The main metering jets are Rochester, which are very similar to Holley. The difference is the threads – Rochester are ¼”-28UNF, whilst Holley are ¼”-32UNEF. Rochester made some sidedraught carburettors (the R and RC models), though these carburettors look nothing like them. The cross drilling is covered by a steel main metering jet plug, which are ½-20UNFx5/16” with an integral washer and 7/16”AF head. The top of the main metering p***age is fitted with a screw-in main metering air-bleed. The main metering air-bleed is 3/8-24UNFx3/8”, drilled to 0.039” diameter. The fourth p***age is the idle p***age. The bottom of the p***age is press-fitted with a 0.093” internal diameter br*** seat. The top of the p***age is fitted with a screw-in idle air-bleed restriction,. The idle air-bleed restriction is 5/16-24UNFx1.05”. The idle air-bleed restriction is screwed into the idle p***age, and bottoms out (seats) on the br*** seat. The idle air-bleed (which controls the air flow) is drilled to 0.028” diameter. The idle emulsion-bleed is drilled to 0.033”. Whilst in theory this drilling should control the fuel flow, there is also a restriction where the air/fuel emulsion flows from the idle p***age into the main carburettor throat. The carburettor throat has only been drilled to 0.038” diameter. Thus the combination of the 0.033” emulsion-bleed and 0.038” carburettor throat drilling will control fuel flow. In addition, the four p***ages have been cross-drilled twice. The first cross-drilling at 11/32” below the top of the float bowl/metering block, connects the air-bleed inlet, main fuel discharge and main metering p***ages. However, the air-bleed inlet p***age cross-drilling is blocked off with a br*** sleeve. The second cross-drilling at 27/32” below the top of the float bowl/metering block, connects the main metering and idle p***ages. The first cross-drillings is sealed at the metering block edge with a drive plug, whilst the lower cross-drilling is sealed with a lead plug. When the engine is at idle, the throttle plates are near closed. A strong vacuum is formed downstream of the throttle plates, and air flows into the engine. At the idle position the throttle plates are located such that the idle p***age drilling is exposed to engine vacuum. The vacuum causes fuel to be drawn from the float bowl, through the main metering jet and up the main metering p***age. The fuel flows through the cross drilling, and up the idle p***age before p***ing through the idle emulsion-bleed. The tip of the idle air-bleed tube is submerged in fuel, and air is drawn in through the air-bleed, forming an emulsion in the idle p***age. The idle air bleed also acts as a vent to prevent siphoning of fuel from the idle system at high speeds or when the engine is shut off. The emulsified fuel flows through the br*** seat, and out into the carburettor throat. Because the idle emulsion-bleed (and idle carburettor throat drilling) is much smaller than the main metering jet, the fuel flow is controlled (metered) by the idle fuel restriction (and idle carburettor throat drilling). To change the idle quality, the idle emulsion-bleed can be made larger (making more fuel flow) or the idle air-bleed can be made larger (causing more air to flow, leaning out and emulsifying the fuel). Note however that if increasing the idle emulsion-bleed much larger, the idle carburettor throat drilling will soon become the restriction controlling idle fuel flow, and will also need to be increased in size. As the throttle is opened further, the vacuum behind the throttle plates increases. Fuel continues to be drawn into the idle circuit, but is also pulled higher up the main metering circuit. The fuel thus flows from the fuel bowl, through the main metering jet, up the main metering p***age, through the cross-drilling and down the main discharge p***age. The tip of the main metering air-bleed tube is submerged in fuel, and air is drawn in through the air-bleed, forming an emulsion in the main discharge p***age. The emulsified fuel flows through the mitred main discharge jet and out into the carburettor throat. The fuel flowing out the main discharge jet is controlled (metered) by the main discharge jet. To change the engine fuel quality, the main discharge jet can be made larger (making more fuel flow) or the main discharge air-bleed can be made larger (causing more air to flow, leaning out and emulsifying the fuel). Of note, the carburettor has no transition, power or accelerator circuits. If the carburettor is snapped wide open from idle, a lot of air flows through the throttle plates. The engine leans out, and will either pause or lean backfire. Equally, as the carburettor is moved slowly from idle to wide open the carburettor will initially run on the idle circuit. The fuel mixture will lean out as the throttle plate is opened, up until the point that the main metering circuit begins to flow. At this point, the mixture will rapidly become richer. This performance will give a noticeable effect on engine speed/power when accelerating. With no power circuit there is a risk of insufficient fuel (and either loss of performance or pinging) under load. This would be controlled by running a main metering jet of sufficient richness to cover the worst case load. Realistically, the carburettor has been designed to be in only two states – idle, and flat-out. This makes it useful for drag racing and speedway use, though less useful for street or circuit racing. The float level is set similarly to an EE Stromberg, by bending the br*** tab on the end of the float. Care needs to be taken in setting float level as the cross-drilling between the idle discharge and main metering p***ages is quite low in the float bowl (exactly the middle). This means that if the fuel level rises above the 50% mark, the float bowl will overflow through the idle circuit. I’ve gone through and stripped down, cleaned and rebuilt the carburettors. The next step will be to make up some aluminium adaptors to adapt the 3-bolt flanges back to the SU 4-bolt pattern. I’ll then give the sidedraughts a test run on the twin-SU manifold on my test mule Holden grey motor (an inline 6 on an engine cradle). As it appears that the sidedraughts are set up for methanol, and will overfuel on petrol there is a pretty fair chance I set the driveway on fire again Cheers, Harv
Excellent write-up. I vote with the Carburetor Service Company in Sydney, I think they were done in small quan***ies by an independent. But I am certainly guessing. But think about Riley, in the USA. I have heard total production of Riley carbs was in the 200 unit range, but I don't think anyone knows for certain. But the Riley castings were very good (actually better than some of the early Rochester castings). And for calibration parts, Riley purchased O.E. parts which were common (Stromberg and Holley parts for Ford). No need to machine these parts if you can easily buy them in various calibrations. There is a variant of the Riley in which is cast the name Flynn. The Flynn castings I have seen are not of the same quality as those by Riley. As to your guess about Stromberg: I haven't seen all of the non-USA-produced Strombergs, but every USA-produced Stromberg that I have seen, and I have seen most of them, and am the current caretaker of the original drawings, had the Stromberg name on the carburetor. You obviously did your research on period sidedraft carbs. You did miss a couple of Zeniths, the 80 and 82 series, but your carbs are not those. Very few individuals are aware of the Rochester sidedrafts that you mention. Carter also produced some fairly large type N sidedraft carbs for small engines (but some small engines are larger than others). And Stromberg produced some fairly large sidedraft 2-barrel carbs during WWII for use on tanks. I would suggest checking with some of the older Australian hot-rodders, and possibly newspaper or magazine articles about the cars that you are aware that used these carbs. Also, Glenn Smith outside of Brisbane might have some answers, as he has cast several body castings for some of the USA-produced Strombergs. Good luck with your project. Jon.
Thanks Jon - appreciated. I was hoping you would post, as your knowledge is excellent. Appreciate the lead on Glen Smith. I've done a heap of work trying to preserve the Aussie Stromberg history, and have written it up as I go as a guide. We used variants of the BX and WW carbs, both locally made and imported, from the 40's through to the 80's. A copy of the original guide is here: http://www.scribd.com/doc/68315221/Carburettor-Guide, with the first addendum here: https://www.scribd.com/doc/23822361...ft500noi&source=impactradiu***edium=affiliate. It's a bit of a work in progress, as I need to add some more info on the Aussie WWs. Cheers, and thanks again, Harv
Harv - absolutely great reference on the Australian Strombergs! I have bookmarked it for some serious reading. A few items of trivia for you: (1) Stromberg-USA codes run from 1 to 268 inclusively (I don't think there are any skips). (2) Both Stromberg-USA and Zenith-USA were independent companies that were acquired by Bendix Aviation, somewhere around 1920. Bendix was the parent company. So Bendix was to Stromberg as GM was to Chevrolet. (3) There are both Zenith and Stromberg companies with some affiliation in several countries. Zenith was originally a French company. (4) Stromberg-USA carbs were originally sold as Goldberg, but this quickly changed, as there was apparently some religious bias. (5) Somewhere around here (unless I sold it, and I don't remember selling it) I have the Stromberg prototype BXOV-1 for Holden that I acquired from Bendix with a lot of other Stromberg stuff. (6) Many in the USA are aware of the break-up of A T & T under the anti-trust laws by the U.S. government. Few are aware that Bendix met the same fate. Both Stromberg-USA and Zenith-USA were bought by Facet Industries. Jon.
Now that is cool! The BXOV-1 was the Aussie GM Holden workhorse carb from 1948-1963 (the only carb GM Holden used). They were also the go-to carb for Holden twin and triple carb hot-up work (and still are). I tried to piece together the history of how we got that carb (see below), though there was a lot of inference in my research. If you can find it, I'd love to see of a photo of the prototype. Stromberg carburettors have featured on General Motors Holden (GMH) vehicles from the first 48-series (FX) in 1948, through to the demise of the VB Commodore in 1980… a run of some thirty three years. The Stromberg Carburettor Company started out in Chicago, Illinois (East 25th Street) around 1906. It moved to South Bend, Indiana after acquisition by Bendix in 1929. Even though aviation sales were only eight percent of the company's revenue in 1929, Bendix renamed his company the Bendix Aviation Corporation and retained that name until 1960 when it reverted back to Bendix Corporation. The South Bend name is cast into the float bowls of some GMH Stromberg carburettors, though I have only seen 23-105C carbs (~early 1950) from South Bend (cast Stromberg Carburettor South Bend USA). Stromberg then moved to Elmira, New York in the late 1940s. The Elmira name is also cast into some GMH float bowls. I've seen both 23-105C, and the later 23-105D carbs from Elmira (cast Stromberg Carburettor Elmira NY USA). Note however that Willys also had manufacturing facilities in Elmira, having acquired control of the Morrow Manufacturing Company in 1914. To make matters even more interesting, the Eclipse Machine Company (also in Elmira) was manufacturing Stromberg carburettors post WW2. So whilst South Bend and Elmira are cast into some Stromberg float bowls, it is likely that the name represented the head company location, rather than the actual manufacturing facility. The later 23-3000 (late FC-EJ) and 23-3001 (EK/EJ auto) carbs that I have seen all have Sidney cast into the float bowls (cast Stromberg Carburettor Bendix Technico Sidney Australia Licensed by Bendix Aviation Corp). It's pretty apparent that "Sidney" is really "Sydney" misspelt, given that "Australia" is also cast into the carbs. Funnily enough, Bendix did have a manufacturing plant in Sidney, New York - they had acquired Scintilla, who were operating from Sidney. As the main body (with the cast Elmira etc) is separate from the airhorn (with the stamped 23-3000 etc), it is possible for carbs to have been mismatched over the years (i.e. the above is a rough guide only). The complexities of exactly which factory was producing the carburettors has been lost over time due to the complexity of the Bendix group of companies. Having said that, it is apparent that the early Holden BXOV-1 carburettors were made under contract by American Bantam, a company once known as American Austin Company. American Bantam fitted the BXOV-1 to the 2,675 Bantam Reconaissance Cars (BRCs), which are recognised as the original ¼-ton "Army Jeep". The BXOV-1 was also fitted to the model 77, 440, CJ-2A and CJ-3A Willys. I suspect that American Bantam ceased making the Stromberg BXOV-1s when the BRC production ceased in December 1941 (American Bantam continued the war effort making trailers). Whilst the BRC Detroit facility was acquired by the US War Requisitions Board in February 1942, I suspect American Bantam kept the carburettor tooling, and supplied Holden (Australia) with carburettors from 1948. I'm not sure where American Bantam did this manufacturing from… probably the same place they had been making the BRCs and trailers (Butler, Pennsylvania), despite the El Mira NY casting marks). This supply (American Bantam US-made BXOV-1 carburettors to GMH Australia) continued through to 1956… coincidentally the exact same time that Armco Steel Company bought out American Bantam. Apparently at that time the carburettor tooling was sold by American Bantam to Holden to make their own carburettors in Australia. I've tried chasing down more of the American Bantam link, but hit a dead-end despite going through the US car club. Interestingly, according to the Stromberg Carburettor Company catalogues, the first WW carbs used by Holden were also made in the US (HR/HK/HT/HG carbs 23-201, 23-201A, 23-201B, 23-202, 23-202A and 23-202B). This was no earlier than 1966 though, well after the demise of American Bantam... I’m not sure who made the early WW’s on GMH's behalf. Cheers, Harv
For the curious, the carbs above are mounted to cast ally manifolds to suit a GM Holden grey motor aftermarket cylinder head. The HighPower crossflow heads were made by Repco... only a couple hundred made. The heads ran either the original BXOV-1 Strombergs, SUs or Webers. The use of these mystery carbs is unusual. I have a second set of ally manifolds, sold by the same seller, that ran early Aussie mechanical fuel injection. The fuel injection is very, very different... low pressure, injecting through holes in the throttle plate spindle (no nozzles). Cheers, Harv
A short update on these Winfields. I purchased them as they had some manifolds to suit a historic Australian inline-6 cylinder head. My plan at the time was to buy one of those heads, and drag race it. Over the last few years I finally found a head (the Repco Crossflow Head), and am now close to having it in an operable state. The heads are hard to come by… Repco only made 200 of them in the 60’s, and most were lost during racing. My plan is to run the head on a Holden 138ci engine, blown, in a front engine dragster. The dragster is nearing completion, and most things are coming together. The reality is starting to sink in that I will never have an engine that would suit the use of the Winfield carbs. Drag racing is hard on gear, and there is more likelihood that I would do damage to them. It seems a shame to have them sitting on a shelf, when perhaps others will get more use out of them. After some checking, I've made a contact at the Museum of American Speed in Lincoln Nebraska. They are interested in displaying them, so the carbs are on their way to their new home to Nebraska. Cheers, Harv
I realize that drag racing is hard on parts, but never thought a carburetor would be a victim. Or or you thinking in general to the Drag racing in whole?
Drag racing as a whole. Stuff gets taken on and off the car repeatedly. Tools get dropped, fuel and oil spilt etc. Not so bad on day-to-day stuff, but would hate to accidently drop a 90 year old carb and bust the air horn out of it. As far as the experts can tell me, there are only 6 of them left, the rest in private collections. Cheers, Harv
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