# Quik Quest. -Dellorto 40 DHLA & Vacuum Advance



## ens (Dec 14, 2006)

im new to carbs, and have a quick question.
the car i baught is running 40mm dhla carbs with a vacuum advance distributor, but the vacuum is tapped off at the distributor.
Can i tap the vacuum from the dhla carb?
thanks in advance


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## anachronism (Mar 8, 2004)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

my question is kindof similar. I am putting a 2 litre inline four out of an audi into a '71 bay window van ( kennedy engineering products adapter kit) I have put an 8 valve counterflow head on the block, blocked off the injector ports, found a sidraft dellorto and manifold for it ...but I don't know what to do about ignition...I was going to drop an early vacuum advance carb in it from a rabbit...but didn't know if I should tap vacuum from somewhere....block off the vacuum advance...or go for a centrifugal advance carb
sorry for hijacking


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## ens (Dec 14, 2006)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (anachronism)*

its cool, your not hijacking your trying to findout the same info i am.


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## anachronism (Mar 8, 2004)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

I am getting th eimpression , we might not be the only ones who don't know!


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## ens (Dec 14, 2006)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

again the info i am looking for and cant seem to find
does the dhla carb unit have a way to tap into the vacuum?
what i'm trying to do is setup a vacuum for my ignition distributor.
thanks http://****************.com/smile/emthup.gif


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## B4S (Apr 16, 2003)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

Unless the carb has a vacuum port that is getting 0 inches of vac at idle, you have to run the can unplugged. The vac advance dizzies also had a centrifugal advance mechanism, so you can run them without the vacuum and still have a decent timing curve. You'll be without the cruising advance, so your fuel economy might decrease slightly, but it won't be the end of the world http://****************.com/smile/emthup.gif.


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## ens (Dec 14, 2006)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (B4S)*

lol i thought about that.. and was hoping for a better solution, msd it is.
with msd the vacuum distributor has to be removed?


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## B4S (Apr 16, 2003)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

The problem with the MSD is that in itself the 6A or 6AL only increases the spark IIRC, not create a timing curve. You'll have to get an add-on to go with the MSD, which adds to the final cost. If you get both boxes, then you need to get a digi dizzy. 

Just looked it up, you'd need to add an MSD 8980 to the 6A or 6AL to create a timing curve. The rumor that the 6 series boxes 'creates' a timing curve if you reverse some wires, is just that, a rumor. 

_Modified by B4S at 4:14 PM 12-3-2007_


_Modified by B4S at 4:18 PM 12-3-2007_


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## ens (Dec 14, 2006)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (B4S)*

thanks alot for sharing your experiance/knowledge
you def. saved me alot of time
thanks http://****************.com/smile/emthup.gif


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## B4S (Apr 16, 2003)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (ens)*

No prob man, just relaying what I've learned since snagging some DHLA 40s for my own car recently







. 
I found this site: http://www.alfabb.com, and there is a lot of useful info there about Dellorto carbs in their Carburetor forum. It's an alfa romeo site http://****************.com/smile/emthup.gif.


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## Kaddy (Sep 29, 2002)

*Re: Quik Quest. -Dellorto 40 DHLA & Vacuum Advance (B4S)*

I went through this same ordeal a few years back with my DCOE setup.
Vacuum advance distributors need ported vacuum (as someone here mentioned), which means zero vacuum at idle, tapering to full signal at part throttle, and then tapering back to zero vacuum at moderate/full throttle. Some of the old SK carbs were tapped with ported vacuum ports, but I dont know of any other sidedrafts that were.
It's not recomended to use a manifold vacuum source, because then you'll get full vac advance at idle, which tapers off as soon as you crack the throttle - not what you want. So if you dont have a ported vacuum source you're best of relying on just the centrifugal advance on the distributor, like your current setup.
The best solution for the money, in my opinion, is the Electromotive HPX or HPV ignition units. They usually pop up used for fairly cheap and allow you to adjust your timing curve quickly and easily. The Electomotive ignition unit will certainly be more reliable then anything with the MSD name on the box too


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