# Dellorto DHLA 40 on a 1.8 8v. Need some help



## Ricky Rockstar (May 25, 2003)

Was running a single Dellorto DHLA 40 on a 1.8 8v with a header back exhaust and stock cam. The idle was good at about 1100rpms, but A/F was around 17:1.
Under part throttle the A/F was 13:1-15:1 and under full throttle the A/F was solid at a little over 15:1.
cruise at almost any rpm was 11:1-high 12:1.
The carb has 142 mains in 7772.11 emulsion tubes, 58 idle jets in 7850.9 holders and the venturi is 7848.1 and the chokes don't have a size on them, but they are about 1 and 1/8 inches in diameter at the narrowest part.
The car ran good with this set-up and pulled hard, but the odd A/F worried me a little.
I'm about to swap in a hydro head with a 276 cam and I want to make sure that I take care of the A/f issues before I do this.
From what I've been reading the idle jet is a little big and the idle jet holder is a little lean, by maybe 2-4 sizes.
The emulsion tube is also recommended to be at around a .6 or .7, not the .11 that it is, which I can't even find listed to see how it fits into the lean-rich scale.
The mains are also a little lean from what I've been reading, but with the cruise as rich as it is, I'm afraid to change it to anything bigger.
The real problem, of course, is that I can't find ANY of the parts I need in order to play around with this thing. Main and idle jets I can find. Everything else is either import from Australia or England it seems, and very limited in availability...
anyone have any suggestions on what I should be running or where to find parts?


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## B4S (Apr 16, 2003)

*FV-QR*

Ok, if you're running an emissions spec dellorto, your idle holder and aux vent is completely wrong, unfortunately.
Pop the jet cover off, does it look like this?








If so, you'll need to switch to a non-numbered idle holder from an emissions carb. Those emulsion tubes you have were only used in the emissions carbs, and completely useless in a universal model. Just the same, if you try to put a .6 or .7 in an emissions carb, it'll run like poo. You need to run 58 idle jets in emissions holders, a .3 aux venturi to keep the mains from starting waaaaaaaaaaaaaaaay too early (which is why you're cruising at 11-12:1, the mains are overlapping the idles). The .1 vent is for a 1.3 and smaller engine, it requires very little vacuum to start the mains. The .3s are exactly what you need for a 1.8 with the .11 tubes. Alfa1750 on ebay has wicked prices, amazing shipping speeds, and even though he's in Italy, he's the best guy to deal with for parts. I'm running a set of emissions dellortos, probably the same kind you have, and cruise at 15:1. My WOT is 13:1, and I idle at 13:1







.
The biggest problem with Dells is that people try to tune them the same way they'd tune a Weber, and that's not the way to go about it. The Dells were used as OE carbs on Alfa Romeos and many others, during the 70s when the emissions regulations were starting to get tighter, so they have some modifications that make them a bit...different to tune.


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## Ricky Rockstar (May 25, 2003)

The carb is a 40C, so its not an emissions carb, sorry I should have mentioned that, but I was in a hurry.
Its starting to look like I have a non-emissions carb full of emission parts :/


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## B4S (Apr 16, 2003)

*FV-QR*

Yeah, then you definitely need to get those .11s out of there. They're too 'holey' for the performance carbs.
I've got a few sets of tubes I can't use, .2s, .4s, and .6s....







.


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## Ricky Rockstar (May 25, 2003)

If I'm measuring the chokes right they're 30s...
So I guess that means I'm looking for a set of 34s and 36s.
And then some bigger mains, probably a set of 150, 155, and 160 to start off with.
I just want to get this thing in a state where it wants to run right.


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## B4S (Apr 16, 2003)

*FV-QR*

You could always machine out the 30s to 34s and see what happens. I had a set of 37s like that, 'custom' machined







.


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## Ricky Rockstar (May 25, 2003)

*Re: FV-QR (B4S)*


_Quote, originally posted by *B4S* »_You could always machine out the 30s to 34s and see what happens. I had a set of 37s like that, 'custom' machined







.

I thought about that, I have a friend that works at a machine shop too. 
I used to work at a vintage sports car shop a while ago, its possible that they might have some laying around, I know one of the owners kept a **** ton of carb parts horded in a room, and since they raced Alfas its a pretty good bet that they will have Dell parts...


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## B4S (Apr 16, 2003)

*FV-QR*

Most DEFINITELY







.
Keep me posted about the tubes. If they don't have non-emissions ones, I can send those .6s as soon as I hear from you http://****************.com/smile/emthup.gif.


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## Ricky Rockstar (May 25, 2003)

I sent you a message back, send me your paypal, if they don't have any tubes at the shop I'll send you money this afternoon.


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## B4S (Apr 16, 2003)

*FV-QR*

IM sent http://****************.com/smile/emthup.gif.


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## B4S (Apr 16, 2003)

*FV-QR*

Pic sent







.


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## Ricky Rockstar (May 25, 2003)

*Re: FV-QR (B4S)*


_Quote, originally posted by *B4S* »_Pic sent







.

awesome! thanks again man!
now I just need to find some chokes, or get mine machined out...


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## B4S (Apr 16, 2003)

*FV-QR*

I'd try to find some .2 or .3 vents too, the .1s start waaaaaaaaaaaaay early and taper off too soon for anything larger than a 1.3. Any old dell from the 70s would have them, all the emissions carbs came with the .3s.


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