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Discussion Starter #1
Hi folks !
Just found a pair of 32s on Craigslist for the Super and wondered about a couple items....
These have 'vacume ports' near the butterflies. My older DCOEs dont have this. Function ?? Can a manometer be hooked up here for ballancing ?
Different idle mixture screws from earlier 40s....carb body made for this type.
Do these adjust the same as the tapered ones ?
Jetting is as shown for 1750/2.0 cars, except the mains were drilled out to 150.
The PO had these from an Alfetta sedan (also has a set of chrome tube headers if anyone is interested ).
 

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Thant's the pre-emission control idle adjust screw. Takes fuel/air from the idle jet circuit and feeds the engine. To properly set these, the throttle plates should be fully closed and these screws adjusted to provide smooth and even idle.

R
 

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I have a unused set too. I intend to put them on a "Sperry" fully ported head and manifold I have had tucked away for years in the corner of the garage.
The main chokes are 32 mm which works quite well on my stock Spider engine.
All the Weber books ( the charts ) indicate a 2 litre needs main chokes at
35 mm. Guess I will become a better friend of Pierce Manifolds on the web. They seem to be the only ones that stock Weber chokes in the 35mm and 36mm sizes. If you haven't checked out there web page - do so.
What's the stack of nickels for? Adjusting Valves?
Bud Feigel
Lexington, Ky.
 

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Discussion Starter #4
They should work well for the Sperry head.
Do you know what the idle mixture screws look like ? All of my 'pre emissions' webers have a screw that looks like the one in this picture.......
Also, none have the vacume ports ( the brass plug between the mixture screw and the transition port plug).
I wondered if the bodies are later than the '32' labeled tops.
 

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There are good reasons not to put those big venturis in 40DCOE's. Alfar7 has given a good explanation - do a search. I have 34's in mine and with hindsight I may have been better with 45DCOE's.
 

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Discussion Starter #6
He may mean 33 mm chokes, althou I haven't seen those listed from any of the big parts suppliers.
I have 33 mm chokes in DCOE 45s on my GTV 1750 (Sperry head, high compression) and it works very well.
 

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These have 'vacume ports' near the butterflies. My older DCOEs dont have this. Function ?? Can a manometer be hooked up here for ballancing ?
Which side of the butterflies those vacume ports are located when butterflies are closed (idle), the air cleaners or the engines? If the air cleaners, they are for vacuun advance distributor hose and useless for manometer balancing.
Jorma
 

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What vacuum port are you referring to?

I don't see any vacuum ports in the photo. The silver screw is the idle mixture adjusting screw, the brass screw behind it (away from the engine) is the cover for the butterfly bleed air progression holes. The next brass screw is the cap (and retainer) for the accelerator jets.

BTW - the 40DCOE32 is the original carb for the Duetto and 1600 spider. 1966-68 vintage. There are no vacuum ports on my carbs (which are original 40DCOE32's with modified jets, etc. for the high performance 2L I've built).

The 1600 intake manifold has one small vacuum port in it on Cyl#1 - it's for the small oil vapor line from the crankcase vent plumbing. It also has a large screw-in vacuum check valve on #4.

Robert

PS - I've had 36 mm venturi's on my highly modified 2L with 40DCOE carbs for nearly three decades. There is little difference between using 36 mm venturis on a 40 DCOE vs a 45 DCOE, and that only shows up at top end. The smaller 40 mm carb runs better, and gives better torque below 5000-6000 rpm.
 

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Discussion Starter #9
Robert, if you look closely there are 3 brass plugs below the idle mix screw.
The first is the vacume port.
Second is the transition hole cover.
Therd is the accel. jet cover.
The vacume port into the throat is on the engine side of the butterfly. At idle, this side would have vacume. On the air cleaner side of the butterfly there is no vacume as the butterfly is closed.
 

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Discussion Starter #10
My Shankle cataloge shows the 40 DCOE 32 is fitted to euro 1750 and 2.0 motors. Also the 40 DCOE 2 for those motors.
1600s got 27s (GTV, Duetto), 24s (Supers), 2s (101 Veloce), or 4s (not specified)
All of my 105 models have DCOE 27 or 24 and have no vacume ports.
Any other info on the idle mix screw ? None of my other carbs use this type of screw.
 

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Given all the 40 DCOE 32 carbs (originally fitted to the 1750) I've owned, currently own and have worked on all had/have tapered mixture screws, I'd say, as previously mentioned, that 40 DCOE 32 covers were put on non-32 bodies. Can't say what bodies they are but stepped mixture screws are indicative of emissions carbs, which came after the 32s. I'd have to check the Alfa installed 78s, 130s, etc for vacuum ports (don't recall any) but the possibility exists that the bodies are non-Alfa to begin with.
 

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Discussion Starter #12
Thanks Mr. Jam, that's what I wondered about.
Luckily, all of the internals are right for pre-emission, so it should work well.
Or do I have to up the idle jet as some other emission carbs need ?
 

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What are the emulsion tube and idle jet numbers?
 

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Discussion Starter #14
Idle jet....50F8
Em tube....F9
Air....200
Main.....145
 

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Discussion Starter #15
As the seller also has a Shankle Alfetta header from his car, these may have come from Shankle in their coversion kit.
Jets are just as shown in the Shankle cataloge (except for the mains which have been drilled out)
 

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I had a Shankle kit on my Spider when I first bought it. It had emissions carbs 40DCOE138/139 with F41 emulsion tubes and 55F21 idle jets.
 

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40dcoe117

Here is the screw arrangement on an emissions carb
 

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Well, the stepped mixture screws suggest an emissions carb yet the idle jet and E-tube are stock Series 2 1750. Not to mention the presence of manifold vacuum fittings. Regardless of the 40 DCOE 32 covers, the bodies are unlike any pre-emission DCOE Alfa I've seen.

DCOEs with air bypass screws have these vacuum fittings as well as a means to balance each throat. But your carb bodies have no bypass screws. So I'm currently at a loss as to what they are.
 

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Discussion Starter #19
Wow !
A one of a kind Weber set !!
Good thing I only paid $150....
Maybe someone replaced the idle mix screws with later ones. Looking down that hole, there is no taper going into the throat for the tapered screw......
 

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a fairly unmolested 32 from a 68 1750 spider--in blue:confused: idle, progression & accelerator pump. Thats all.
 

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