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DCNF on Aseries manifold
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Hi, does anyone have a Weber DCNF setup on an A series manifold?

Im cracking my head to create a setup here. I need ideas please. Pics will be excellent. So, if anyone have this kinda setup, i beggg u...pleaseee......

Posted on: 2007/2/20 6:54
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Re: DCNF on Aseries manifold
No life (a.k.a. DattoMaster)
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Hi.
You need to post pictures of your existing manifold, the bottom section of your DCNF and dimensions of your carburetor at the base. There is no way to guess w/o seing the items.
Please post a picture(s)

Posted on: 2007/2/20 17:37
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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Hmmmm, Weber DCNF, available as a 36 DCNF, a 40 DCNF, a 42 DCNF or a 44 DCNF.

These are described as being ......
"Of the vertical downdraught type & each barrel of the carburettor is of identical diameter.

The throttle valves are of the synchronised, simultaneous operation type & are located on a single shaft.

The identification mark is located on the main body on the outer face of the float chamber wall"
----------------------------------------------------------------------------------------------------------------------------------------

Now this is an interesting carb as it has a single transverse throttle shaft, much like American 2bbl carbs on V8's, but this model of Weber carbs uses ball bearings to support the shaft, with a seal each side to prevent air leaks. Very impressive.

Most of these dual throat Weber models use two parallel throttle shafts, running fore & aft, but this one seems to have some of the design features of the IDA & IDF types.
It does not use a conventional choke design, but uses an enrichment system instead & this removes the impediment to airflow that the choke plates & shaft present.

All in all, a very nice carb, but with the smallest version having 36mm throttles, & being of the synchronous opening type, I'd say that it might just be on the borderline of being too much carb for most mild, streetable A series engines. The larger models would only make this worse.

If you have a 36 DCNF, then have a go & see how it runs, but personally, I suspect that a progressive throttle carb will work better on a streetable A series engine.

Posted on: 2007/2/20 22:40
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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I am almost 30% positive the 40 DCNF will fit onto any DGV adaptor.


Wouldn't mind giving one of them a go

Posted on: 2007/2/21 8:06
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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Yes. I understand Dodge's concerns, but I would give it a try. A 36 DCNF might be what the doctor ordered, like a 38 DGAS to an L series.

Pictures.......

Posted on: 2007/2/21 8:09
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Re: DCNF on A series manifold
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Sorry for the incomplete info's mates.
Its a Weber 40 DCNF.

Here are the pics of the carb and a 1200 manifold.

Open in new window


Open in new window

Posted on: 2007/2/21 15:30
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Re: DCNF on A series manifold
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You just need a simple adapter plate. I made mine out of a 1-inch aluminum piece (most people use a 3/8-inch thick adapter). Mine was for the Weber DGV, but it seems very similar. Details are here: adapters

Posted on: 2007/2/21 16:40
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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Congratulations on the great work D Gonz.....that wikipedis looks awesome!

I had an adaptor in my former RHD postal Jeep that was made for the 32/36 into the one barrel manifold ( that 6 cyl manifold had a one barrel carter carburetor...horribly undercarbureted).
The adaptor looked like a funnel. I still have that adaptor in my storage place. Any adaptor can be made.
You can make an adpator following the instructions in the link provided. You need a block of aluminum, big enough to seat the DCNF.It has to be grounded to match the opening of the stock manifold. Look at a 32/36 adaptor so you can get the idea. Then you drill the adaptor to manifold holes, and the adaptor to DCNF holes.
I sent a letter to Weber to find out if there is any adaptors. In this part of the world the DCNF is not marketed, but in Europe, with all the Fiats, Alfa Romeo, Seats,Simcas, Renaults, etc....there is extensive use of those, including Ferraris ( the V12 Ferraris use 6 DCNF carburetors.)
Do not despair. It is not a difficult thing. Do you have a adaptor you can look at, a more common 32/36? Follow that design, that is what has to be done.
Now, if you have access to a aluminum welder in Thailand, then I would cut the center portion of the stock manifold and make a direct bigger seat for the carburetor. Better flow. I think we have a picture of a manifold like that...by Leosnake2000 ( his name here.) real name is Rick.
Let me see if I can find the pix.

after a few minutes....
Got it...I was diving into the 1200 archives.....I had to fight the custodian of the records...he spoke portuguese to me and I spoke english.....I said I can speak spanish too, he said NIET!... we got in a fight....fists flew...I got my sling shot and as I was trying to get the rock in place....he pulled my slingshot off my hands...and.....LOL ..........

....... just kidding.....no need for violence...records were available....

Check this out:
Weber DGV intake

Posted on: 2007/2/21 18:19
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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It looks to be a great carb. These were originally intended to be used on six cylinder engines of about 2.5 litre or larger, so gas velocity through the carb during town driving might be a bit low, but give it a go & let us know how it runs.

EDIT
Is this carb mounted with the throttle shaft running parallel to the crankshaft, or transversely, when fitted to the original engine, & which way do you intend to mount it?

It looks to me as if you want to mount it as it is seen in the photos which will make for an interesting adaptor.
This will place the float to the side of the carb, which is an unusual position, but hey, if it was designed to be that way, then it's all good.
If you mount it as per the photo, then it will be the correct placement of the throttle plates for proper air flow into the manifold.

A transverse shaft works best for V engines.

Oh yeah, you say that the manifold in the picture is for a 1200 [A12] engine? Looks more like an A14/15 one to me & it has nice big runners, so would be the best choice for this experiment.

Posted on: 2007/2/21 18:58
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Re: DCNF on A series manifold
No life (a.k.a. DattoMaster)
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Yes, give it a try, it will not hurt, get a header for your motor so the flow will be a better one. More exhaust flow means more flow in the chamber at overlapping.

The Weber rep responded ( that was fast...cool) he asked me a few questions...he was surprised about the DCNF, but he knows it is a better performance unit. There is no adaptors made ( this is Weber USA) but he suggested modifying a 32/36 adaptor. I responded anking about the 38 DGAS adaptor, which has larger openings.
Perhaps the best option would be to get a DGAS 38 adaptor, no holes drilled on it, and you would have to drill the holes on your car, as they appear to be positioned/required.

I will post the latest responses by the Weber Rep, his name is Bud.

Editing ..........1:10pm

here is an excerpt:
____________________________

You will find modifieing our standard adapter will be the easiest way
to
go. infact on that motor its a one piece adapter and you can fill and
redrill or offset and redrill with no issue at all

and on a 1400 I would go with something like 28mm ventrui and it will
be
a flyer.

for raod racing application you will want to look at float orientation
and lower float level a little and put a spring or stop in the bottom
of
the float well to limit float drop. other wise have fune

we are local to you and in redondo beach you can check with european
motorworks near 190-th and Hawthorn for parts they do a good job or
pick
up parts from us daily

hope we can be of help

Bud Pauge
REdline WEber

________________________________

Posted on: 2007/2/21 19:15
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