engine and drivetrain Getting started on Rebuilding DCOE 40's-What size Needle Valves?

[2002Scoob]

Looking to order my rebuild kits for my Webers, and was wondering if anyone had a quick suggestion on what size needle-valves to order. 

 

They're Italian DCOE32's 

 

Planning on running a 272 or maybe a 292-300 later on in life

[Hans]

Are they really 32s? A bit small for 2 litres.

[2002Scoob]

They're 40DCOE 32's. 

 

They're 40's, but the series number is 32, please do correct me if i'm wrong.

There are the 2's, 18's, Italian 151's, Spanish 151's, etc. etc. etc. I thought they were all relatively the same. 

Edited February 1, 2016 by 2002Scoob

[M3M3]

That second number denotes the different internal drillings for specific car applications.

[2002Scoob]

That second number denotes the different internal drillings for specific car applications.

 

Exactly my understanding. And from what basics I know, 40DCOE32's work with our cars quite well. 

 

Still searching for an answer to needle size, if anyone has a guess, or how I can find out which to order. 

[2002Scoob]

Side note... I was able to pick up these absolutely BEAUTIFUL Lightweight intake trumpets, but I immediately noticed that the inner sleeves do not have clearance to slip them around.

 

Two directions I could go- 

 

1. Machine the outer of the part on the right so that the trumpet sleeves around it, then machine the inner surface slightly to match the ID's of both parts. 

 

2. Source the proper part that could fit these trumpets. Thoughts??? If this is the way to go, where can I find these little guys?

 

[Simeon]

Weber tuning manual here http://www.lainefamily.com/images/WeberTuningManual.pdf provides some guidance on selecting float needles (plus other useful stuff)

[Stevenola]

32's were generally used on Alfa's.  For your engine I'd try 2.00 needles and 34mm chokes.  With your cam (or possibly stock) you may find yourself running out of air at higher rpms if so you'd need DCOE45's.  You don't want to mess with trimmimg the aux venturi, get proper bolt on trumpets from Eurocarb:

 

http://www.dellorto.co.uk/product-category/car-accessories/car-air-filters-trumpets/bolt-on-trumpets/

 

Do you have an afr meter to tune these with?

[2002Scoob]

32's were generally used on Alfa's.  For your engine I'd try 2.00 needles and 34mm chokes.  With your cam (or possibly stock) you may find yourself running out of air at higher rpms if so you'd need DCOE45's.  You don't want to mess with trimmimg the aux venturi, get proper bolt on trumpets from Eurocarb:

 

http://www.dellorto.co.uk/product-category/car-accessories/car-air-filters-trumpets/bolt-on-trumpets/

 

Do you have an afr meter to tune these with?

 

Thanks for the response!

 

I don't have an AFR meter at the moment. I've ordered a few books on tuning and setup that I plan on reading and educating myself with first... 

 

But the plan is to have a local guy who's a oldtimer expert to do my tuning, at least at first, that way I don't mess it up.

 

But what I do want to do is the rebuilding of the carbs and basic setup/bolting it all on myself. 

 

With ya'lls help, if I can get it in the ballpark and then have it towed to his spot, that'd be great. He's also going to be doing the rebuilding of the Head/cam installation too. 

[Hans]

The bolt on ones may be easier to deal with, but you have to consider brake booster clearance, and air cleaner arrangements. I suspect if you search on DCOE40 on FAQ< you will find a plethora of jetting set-ups. 40mm chokes may be enough to get going with stock motor.

[2002Scoob]

Yah, I'm not sure what size the chokes are on the carbs yet, haven't gotten em' pulled apart that far yet. According to the previous owner they came off an '02, so I'm hoping they're at least in the ballpark.

 

Is there a relationship to choke/needle size I should consider? Was hoping to pull the trigger on the rebuild kits soon. 

Edited February 1, 2016 by 2002Scoob

[Hans]

As I recall, there are not that many choices for needle valve. I'd have to look in the book, but I think 1.75 or 2.00 for 40s, but don't quote me. More critical is idle circuit choice, which governs running up to about 3000 rpm or so. If you do the search, you will get a range of settings for the package, and then you can look for correlations. You should also think about a "squirrel cage" sync. tool to balance carbs.

I have a set of short bolt-on trumpets if you go that route.

You should be able to see the choke size embossed on the lip. The rest of the important jets come out the top under the jet cover. I would not go buying a lot of new jets quite yet.

[nbcbird]

1.75 with 32 chokes

[2002Scoob]

32's were generally used on Alfa's.  For your engine I'd try 2.00 needles and 34mm chokes.  With your cam (or possibly stock) you may find yourself running out of air at higher rpms if so you'd need DCOE45's.  You don't want to mess with trimmimg the aux venturi, get proper bolt on trumpets from Eurocarb:

 

http://www.dellorto.co.uk/product-category/car-accessories/car-air-filters-trumpets/bolt-on-trumpets/

 

Do you have an afr meter to tune these with?

 

Looks as thou the carbs are, in fact outfitted with 32mm chokes.

 

I think I'll be sticking with the 272 Alpina cam Ive got sitting around for the head build. 

 

I'm looking on the Dellorto site and i'm seeing auxiliary venturis that looked to have the stepped-down outside diameter that could facilitate my trumpets, yah?? 

 

http://www.dellorto.co.uk/shop/weber-carburettors-parts/carburettor-parts-weber-carburettors-parts/dcoe-dcosp-parts/auxiliary-venturi-dcoe40-spring-clip/

 

 

However, given that I have access to a lathe, I'm tempted to do this machining myself and save the 80 euro for the set. 

[2002Scoob]

So, it's sounding like the feedback is-

 

1.75 with 32mm chokes, which should give better throttle response

 

or

 

2.0 with 34mm chokes, which'll give a bit better top end

 

Does this sound correct? 

 

Honestly, I'm reading through the PDF Simeon posted and it's EXCELLENT for understanding everything thus far. so stoked on it, and I'm not even all the way through.