2 DCNFs on Type 1, do you have experience?

[Jim Ratto]

Another carburetor I have almost no experience with on a VW. I rebuilt a set of 40DCNFs for a friend back in the 90's, but have never tuned them. Don B. I know you have 44DCNFs on your 2.0, do you have any insight on making them run well? If I remember correctly, this is what I know about DCNF's on a VW:

1. The floats operate on the "wrong" axis when installed as pairs. The throttle shafts should be oriented same as axles of the car, not the crankshaft. Can the needle valve be sized/adjusted or the float height adjusted to "compensate" for the carb being turned 90 degrees from its preferred position?
2. Idle jets. Same as IDF model Webers, correct? On the DCNF they are installed in the "ends" of the carbs....making the cyl # 1/3 a real bitch to service and clean?
3. Parts availability? Air horns, air cleaners, emulsion tubes, etc. Still out there?

Sorry, I don't mean to post one of those "gimme some free advice" posts here. If you ran DCNFs at one time on a street car and loved them or hated them, can you share your opinions? Thanks,

Jim Ratto

[Fastbrit]

(holding hand up) Me, me, me! I used them!(/holding hand up)

The problem you describe is true – DCNFs were designed for Ferrari and intended to be used with throttle shafts cross-ways on the car. Turning them 90 degrees to work on a VW meant that the carbs flooded momentarily on sharp corners. The problem was partially solved by Berg, who was a major exponent of DCNFs on a VW, by using (if I remember correctly) extended jet holders or redesigned emulsion tubes – something like that. To be honest, the moment Weber came out with the IDF and Dell'Orto with the DRLA, the DCNF became extinct.

Parts are available, largely thanks to the Ferrari connection.

[Lee.C]

The throttle sharft of my single DCN is "oriented same as axles of the car" and it works awsome 

[Donny B.]

I've been running DCNFs for about 15 years now.  They are the only dual carbs I have had on my engines.  They are awesome when properly set up.  What you say is true about the floats.  Accelerating out of a hard turn (like exiting the local 7-11) you will pin one float all the way open and the other one closed then you end up running on two cylinders until everything catches up.  The trick is to make the turn the get on it.  I still forget.  emulsion tubes are critical to their proper operation.  If you have the wrong ones you will be chasing your tail.  I believe the correct ones for 42s and 44s are f25s.  A good starting point would be 50 idles 180 airs and 135 to 145 mains.  With 42s on my 1776 I ran 135 mains and for a while with the 42s on my 2007 I ran 145s.  Gene told me that the idle circuit is critical on the DCNFs because it is in play all the to almost wide open.  Another thing is to eliminate the enrichment circuit.  The best way is to pin the enrichment pistons down on their seats with a set screw.  I just tapped the carb and bought some set screws and loctied them in place.  I just measured them then went to the local ACE hardware.  If you don't do that they will float off the seats during heavy throttle and enrich everything causing the engine to load up.  The voice of experience talking here.  Let me know if you have any more questions.  They are so smooth on acceleration with no flat spots.  They are great street carbs.  The  velocity stacks are still available if not from the Bergs then from Pierce manifolds in Gilroy.

[Jim Ratto]

cool this is good info. We are considering DCNFs on sheep's engine, possibly in place of 48IDAs.

[sheep]

cool this is good info. We are considering DCNFs on sheep's engine, possibly in place of 48IDAs.

What we are

[louisb]

Here you go, slap a set of these on there.



Only $300 

http://www.thesamba.com/vw/classifieds/detail.php?id=520379

--louis

[stealth67vw]

I have a pair of 42 DCNFs with Fil-Star manifolds and air cleaners collecting dust. I have owned them for 16 years and tried them out on a 1776 I built in 1993. I knew very little about dual carbs and jetting and I could not get them tuned. I pulled them off and put on some 44 IDFs and it ran perfect until I had a CB hydraulic lifter explode taking out my virgin AS21 case.

If you want them, let me know and we'll work something out. They have no stacks and no linkage.

[Zach Gomulka]

Had 42 Specials on my 1776 type 3 pancake motor. Set up by Steve Hollingsworth of V.W. Performance, they ran beautifully, and got great mileage , too. Since the bores are close together and the carb body is relatively short, I think they are the ideal carb for a type 3.

[Jim Ratto]

I have a pair of 42 DCNFs with Fil-Star manifolds and air cleaners collecting dust. I have owned them for 16 years and tried them out on a 1776 I built in 1993. I knew very little about dual carbs and jetting and I could not get them tuned. I pulled them off and put on some 44 IDFs and it ran perfect until I had a CB hydraulic lifter explode taking out my virgin AS21 case.

If you want them, let me know and we'll work something out. They have no stacks and no linkage.

let's talk

[stealth67vw]

They've been sitting in my dad's closet in Alabama since 1994, so they will need to be cleaned up and rebuilt.

[Jim Ratto]

They've been sitting in my dad's closet in Alabama since 1994, so they will need to be cleaned up and rebuilt.

I can handle it, dude.

[Jim Ratto]

I've been running DCNFs for about 15 years now.  They are the only dual carbs I have had on my engines.  They are awesome when properly set up.  What you say is true about the floats.  Accelerating out of a hard turn (like exiting the local 7-11) you will pin one float all the way open and the other one closed then you end up running on two cylinders until everything catches up.  The trick is to make the turn the get on it.  I still forget.  emulsion tubes are critical to their proper operation.  If you have the wrong ones you will be chasing your tail.  I believe the correct ones for 42s and 44s are f25s.  A good starting point would be 50 idles 180 airs and 135 to 145 mains.  With 42s on my 1776 I ran 135 mains and for a while with the 42s on my 2007 I ran 145s.  Gene told me that the idle circuit is critical on the DCNFs because it is in play all the to almost wide open.  Another thing is to eliminate the enrichment circuit.  The best way is to pin the enrichment pistons down on their seats with a set screw.  I just tapped the carb and bought some set screws and loctied them in place.  I just measured them then went to the local ACE hardware.  If you don't do that they will float off the seats during heavy throttle and enrich everything causing the engine to load up.  The voice of experience talking here.  Let me know if you have any more questions.  They are so smooth on acceleration with no flat spots.  They are great street carbs.  The  velocity stacks are still available if not from the Bergs then from Pierce manifolds in Gilroy.

Thanks again Don, I'll be in touch.

[nicolas]

hey if someone else has some sitting in a closet or on a engine i am looking for them as well. but i will put them on short manifolds to use them on a type3.

but maybe allready modded for the use on a VW engine as there is no geneberg shop on the corner.

sorry for jumping on the tread like this

[Fastbrit]

They've been sitting in my dad's closet

Jim likes things that come out of the closet... Or so I heard.

[besserwisser]

I recently built a 1914 for a customer and we started it up with a set of 40dcnf on SCat manifolds. It was a first experience for me but after a good cleaning the motor ran extremly well with superb response on the throttle. Admittingly I have never tried them in a car but I was impressed with the performance of this old little thing. I since then have bought my own set to try on a 1835cc that I built a few years ago. It will be started when I get back from my trip to California (Drag Days) so I will keep you posted.

[Dave Galassi]

I concur with the posts here Uncle Jim, good carbs.......if you are into carbs.  I purchased a new set from Berg for my crew cab and they were great.  Smooth progression off idle and good mileage when jetted correctly.  Easily serviced and well built. It worked well on that engine. 

[sheep]

They've been sitting in my dad's closet

Jim likes things that come out of the closet... Or so I heard.

Man I love this place hahahahahahaha

[John Rayburn]

Did you know that Jim levitates down staircases sideways without touching a single stair?

[sheep]

Did you know that Jim levitates down staircases sideways without touching a single stair?

 

[Jim Ratto]

Did you know that Jim levitates down staircases sideways without touching a single stair?

yeah yeah yeah.....somebody had the foresight to set a frigging booby trap on my staircase with that photo album that matches my carpet almost exactly. And you guys thought I can't stage dive.

[stealth67vw]

Your lucky you didn't break your cockicks like your grandma at the sand dunes.

[Donny B.]

Didn't this thread get a little off topic?  At least it's not nasty like one of the other forums.