Bruce,
Gee, I thought you were looking more for a response like: "Side draft
carburetors are inherently more complicated to design than down draft
carburetors."
But Mr. McEwen is correct. The English class system plus both the prewar and
postwar socioeconomic conditions contributed much to the designs (and design
flaws) inherent in many products from the U.K.
I know lack of design money contributed much to the fall of the British
motorcycle industry, which was forced to rely on outdated prewar engine
designs due to the high cost it would have taken to retool to compete with
the Japanese designs. I also know MG's demise was partly due to the fact
that it was managed so poorly over the years, changing owners each time the
new owner's accountants discovered it was a bad investment.
As for the complexity of these SU and Zenith carbs, I don't think they are
really that complicated. Old age and wear seem to be more of a problem.
Also, as soon as you have more than one carb on an intake manifold, you have
the added headache of synchronization. That's why I take my motorcycle to
the shop for a tune up!
I'm not that familiar with downdraft carbs like a Weber or a Holly, but
doesn't a second butterfly simply replace the sliding piston? I have a Weber
replacement for my B that I will be installing in the spring, so I'll let you
know how it goes.
Answers to your other questions to follow.
don
In a message dated 2/18/01 12:46:40 PM Eastern Standard Time,
mmcewen@ualberta.ca writes:
> Subj: Re: TR7 BFH#56 -- Why are LBC carbs so complicated?
> Date: 2/18/01 12:46:40 PM Eastern Standard Time
> From: mmcewen@ualberta.ca (John McEwen)
> Sender: owner-british-cars@autox.team.net
> Reply-to: <A HREF="mailto:mmcewen@ualberta.ca";>mmcewen@ualberta.ca</A>
(John McEwen)
> To: Eganb@aol.com
> CC: british-cars@autox.team.net
>
> The difference is engineering. There were few if any professional
> automotive engineers involved with the automobile industry in Britain
> during the formative years, a situation which generally persisted until the
> end of the automobile industry in Britain. There was a rigid class
> structure in Britain which caused the working class (all people in the auto
> industry) to look with suspicion and distrust on anyone with a higher
> education. "Designers" were people who had worked their way up through the
> system which saw them join the "works" as boys. What they learned was
> learnt by observation and working with other men who had been educated the
> same way. "Professional Engineer" designations were earned not learnt in
> the years when a man could be declared a P.Eng. by applying to the
> association and standing on his experience.
>
> Upper management was concerned only with shareholders and shareholders were
> concerned only with profits. There was an enormous social and working gap
> between senior management and working management. There was a near lack
> of forward planning and R & D money was almost non-existent. For many
> years R & D consisted of looking at what went wrong with the product after
> it reached the market. Automobiles and their parts were developed by a
> series of "fixes" which added complexity in many cases to an originally
> flawed design in order to make it work - after marketplace testing had
> shown the flaws. The "clean sheet of paper" approach was rarely attempted
> as most "development" was an elaboration of an earlier design. Custom and
> practice ruled construction which in most cases was rooted in the interwar
> period. Design basics remained constants for upwards of 50 years when the
> original design was in many cases obsolete shortly after its inception.
>
> World War II created grave problems for British industry and development.
> Millions of people were killed and injured. British youth died in record
> numbers and this hard-hit generation was itself the children of the equally
> hard-hit generation of World War I. The brightest and bravest died in two
> wars and the economy died with them, leaving a country of destroyed
> factories and old men who had to pick up the pieces. The collapsed economy
> and desperate shortage of capital and raw material meant that British
> society had to continue to shoulder the hardship of the war years while
> attempting to rebuild the country. This was done without the financial and
> administrative assistance given to Germany and Japan for their rebuilding.
> The strain was too much for many and emigration from Britain reached record
> levels in the ten post-war years. Those emigrating were also the youngest
> and most ambitious.
>
> The result was an industry that built things in the "traditional" way and
> which lacked the capacity for all of the above reasons to change.
> Automobile construction was highly labor intensive - which worked in a time
> when everyone needed a job and salary expectations were low. Machinery was
> old and worn while money was tight. The charm and quaintness that we find
> in British automobiles is a direct result of the inability of the industry
> to do otherwise. Weak forward planning and the refusal to accept that the
> new Japanese automobile industry and a resurgent Europe were threats led
> directly to the fall. Yes, major strides were made - compare the TR2 to
> the TR7 - but often the results were disappointing as reliability was dodgy
> and basic improvements were ignored. The cars were still noisy and rough,
> the engines still leaked oil and maintenance was still at the level of a
> '20s auto. The appeal of British cars - except for sports cars - in North
> America was rapidly erased by the continuing failure of the "designers" to
> recognize the needs of a North American car buyer and/or inability react to
> them. American cars continued to improve to the point that they were
> perhaps the best cars in the world - certainly in terms of reliability,
> comfort and longevity. It was hard to sell an Austin America or Marina to
> people who could buy a Chevy Nova or Dodge Dart for the same money.
>
> A major concern regarding your carburetor question is that American
> carburetors were sold in the hundreds of millions whereas the British
> market was considerably smaller. It is not difficult to continually re-tool
> and improve a product when sales and profit figures are so large. As and
> example, the two most reviled American cars of the '70s were the Vega and
> the Pinto yet between them there were nearly 17 million produced. I doubt
> that the British automobile industry has yet produced 17 million cars in
> total - certainly not if the Mini (5 million plus) is excluded. Finally,
> the American practice of continuous model change and engine upgrading
> required continuous improvement from the carburetor companies which were in
> fierce competition in the industry.
>
> In Britain, labour problems in the '60s - from a workforce which had
> endured the rebuilding of the '50s and hoped for the expected reward of
> hard work - were endemic. Modernization was difficult due to the very
> large work force and the government's need to keep employment high. A
> late 50s boom in auto sales and production led to amalgamation, redundancy
> of work force and labour attempts to provide for their brothers. Falling
> sales coupled with the resurgence of the European auto industry and the
> high taxation/pricing policies which persisted led to a slump. The
> motorcycle industry died first - for the same reasons - then it was the car
> industry's turn. In the '70s, Labour governments went heavily into job and
> industry protection when the reality was that the industry was already
> dying and competition from Japan and Europe was firmly established. By
> mid-70s, it was increasinly difficult to sell British cars even to the
> British when so many better cars were available at similar money.
>
> The result is that today most of the British auto industry is
> foreign-owned. The largest British-owned manufacturer is TVR which began
> life as a fiberglass kit car. Britain has made great economic strides but
> its auto industry was one of the casualties. Many of us love and enjoy the
> automobiles and motorcycles of Britain in spite of, and maybe because of
> the conditions which created them. Hopefully, we'll continue to enjoy them
> for many more years.
>
> John McEwen
>
> Austin, Jaguar, Jensen, Lagonda, Lotus, Standard, Triumph, Vauxhall
>
>
>
>
>
>
> >Probably a dumb question on my part, but why are SU and Zenith-Stromberg
> >carburetors so complicated, compared to something like a Holley or
> Rochester
> >carb?
> >
> >I'm always amazed at all the separate components that make up the carbs
you
> >find on LBCs, whereas a Holley four-barrel proabably has less than half
the
> >moving parts.
> >
> >Must be a reason for the different technology.
> >
> >Anyone?
> >
> >Bruce
> >1980 Inca Yellow TR7 5-speed convertible
> >Chapel Hill, NC
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