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Interesting manifold and carb… - Ruairidh Dunford - 09-11-2023
We’ve had these cast manifolds and carb for some time, I’ve not seen the inlet manifold/carb combination before.
Does anyone else have one, and does it work well?
RE: Interesting manifold and carb… - MartinH - 09-11-2023
If that carb is as large as it looks then an awful lot of revs will be needed, or something more than 748cc.
RE: Interesting manifold and carb… - Ruairidh Dunford - 09-11-2023
David Offer has just posted this on my FB post:
“This image in "A History Of The Dante Engineering Company" shows the same manifold I think.
By the end of 1956, they "listed inlet manifolds for single and twin Ford 8 carbs and for the Ford V8 twinchoke type 'discovered' by Colin Chapman and for which virtually no demand materialised"
RE: Interesting manifold and carb… - John Cornforth - 10-11-2023
Hi Ruairidh
Here's some background information from the makers, before the days of the trades description act !
Extracts from the Sixth Printing of the “A7 Textbook” by The Sporting Motorist’s Agency Limited, suppliers of DANTE speed equipment for the Austin Seven.
AUTHOR’S NOTE.
The A7 Textbook has gone from strength to strength and more than 1,000 copies have been sold since it was first introduced in May 1956. This booklet is now accepted as a standard work on the fascinating subject of Austin Seven “Special” Building, and we have pleasure in introducing yet another printing for distribution to enthusiasts wherever they may be, at home or abroad.
We are also gratified to find that there are other booklets dealing with the improvement and modification of the A7, for imitation is the sincerest form of flattery. However, the original should not be confused with its imitators, so look for the name “THE SPORTING MOTORIST’S AGENCY, LIMITED.”
D.A.S. FEBRUARY 1957.
6) Carburation, etc.
One of the first steps towards boosting the performance (speed and economy ) of the car is to improve the “breathing” qualities of the engine. This is most simply achieved by fitting one or two downdraught carburettor(s) on a special inlet manifold; a step which will be found to give an immediate improvement in performance. A double carburettor gives better power but is naturally a little more complex to tune, etc. Suitable carburettors include the Ford 8, Solex type 26 A.I.C., Zenith V.I.G 30mm. The special inlet manifold should be used in conjunction with either the DANTE exhaust manifold or the pre-1932 standard exhaust manifold, which can be supplied by The Sporting Motorist’s Agency Limited, if required. If your car has a scuttle tank, an S.U. electric fuel pump should be used to assist fuel feed to the downdraught carburettor(s). Further improvement in performance whilst retaining the standard exhaust manifold, will result from the use of a silencing system as described in Section 7 below.
All flanges and ports must fit perfectly and there must be no sharp edges or protrusions to impede the gas flow anywhere at all. Internal polishing of the manifold and ports is only of secondary importance to this.
7) Exhaust System.
You may perhaps have regarded with horror the tortuous path taken by the exhaust gases of a standard A7 engine when escaping to the open air. A great improvement in performance is given by fitting the DANTE cast alloy “bunch of bananas” type exhaust manifold which combines the advantage of low weight with free gas flow to the silencer and tailpipe. The benefits of good manifolding are not fully realised, however, until a “straight-through” exhaust system has been fitted, and a motor cycle silencer devoid of baffles, with narrow-bore tail pipe (7/8” or 1” internal diameter) will give good gas extraction.
RE: Interesting manifold and carb… - Ruairidh Dunford - 10-11-2023
Thank you, John, it all seems so simple!
RE: Interesting manifold and carb… - Howard Wright - 10-11-2023
Hi Ruairidh
In my teens I was an avid follower of American custom cars and drag racers. Holley carbs were de rigueur on the best cars. It looks a bit over the top for a Seven though.
Cheers
Howard
RE: Interesting manifold and carb… - Henry Harris - 10-11-2023
The Dante 'twin choke inlet manifold' was a very poor imitation of the Lotus set-up but without the de-siamesing.
They were used with a 1930's 60hp Ford V8 Stromberg 81 twin choke carburettor.
The carb on your manifold is a modernish, progressive Holley Weber from something European.
RE: Interesting manifold and carb… - AustinWood - 10-11-2023
I believe that is a 'double carburettor' where there is one float chamber feeding effectively two carburetters each a with choke and a complete set of jets etc in one body.
In that set up one side feeds cylinders 1 & 2, the other 3 & 4. The air flow through each is not very constant. Cylinder 4 follows 3 immediately and then there's a gap while the other side feeds 2 then 1.
The Lotus system I believe was set up so that one choke fed 1 & 4 and the other 2 & 3 thus giving a more evn flow, With the inlet ports desiamesed the problem of charge robbing was avoided where one cylinder would take some of the mixture meant for the other cylinder which shared the inlet port.
The Straight-8 Daimlers used a similar sysem with a double Stromberg carburetor feeding cylinders 1,2,7&8 from one choke and 3,4,5&6 from the other. The Ford V-8 also used the Stromberg carburettor with each choke feeding one side of the engine.
RE: Interesting manifold and carb… - Ruairidh Dunford - 10-11-2023
(10-11-2023, 03:29 PM)Henry Harris Wrote: The Dante 'twin choke inlet manifold' was a very poor imitation of the Lotus set-up but without the de-siamesing.
They were used with a 1930's 60hp Ford V8 Stromberg 81 twin choke carburettor.
The carb on your manifold is a modernish, progressive Holley Weber from something European.
Yes, that is correct, I believe it is indeed of these: https://www.ricambio.co.uk/reconditioned-carburettor-holley-30-dic-11-fiat-850
RE: Interesting manifold and carb… - Ruairidh Dunford - 10-11-2023
Thank you for explaining that, Jim.