AC Owners Club Forum

AC Owners Club Forum => 3000ME Forum => Topic started by: IanBrown on July 18, 2018, 16:58:34

Title: Triple Weber 40 DCNF
Post by: IanBrown on July 18, 2018, 16:58:34

Hello,
Has anyone got them fitted?
Any idea on carb set up as a starting point?
- main jets
- air correctors
- emulsion tubes
- idle jets
Any pictures of cable set up and choke?
Regards
Ian

Title: Re: Triple Weber 40 DCNF
Post by: administrator on July 19, 2018, 09:03:52

Barrie Bird ran 169 on triple Webers and I think Specialised Engines had the installation on their demonstrator, but I haven't seen any recent installations.  There is a photo in 'AC Heritage' by Taylor and Burn:

Title: Re: Triple Weber 40 DCNF
Post by: IanBrown on October 10, 2018, 23:27:15

Hello,
Does anyone have an more photos they could post. I'm interested in seeing how the throttle cable mechanism is set up.
Thanks
Ian

Title: Re: Triple Weber 40 DCNF
Post by: B.P.Bird on October 12, 2018, 11:59:48

Ian,
So long ago, but from memory Ford supplied three pivot blocks which fitted the Weber butterfly operating arms. The blocks were simply linked by a threaded 2 BA rod and synchronisation was easy by moving the blocks along the rod and then locking them in place with 2 BA nuts. I think the throttle cable was linked on the No. 2 carburetter. However all your queries would be answered if you could lay hands on my ME file which I included when I sold '169 . Maybe the file is still with the car ? Worth asking the owner. All sorts of details were in it including the shorty exhaust manifolds, Hyvo chain set up, gearbox uprate and heated screen wiring. Never a good idea to reinvent the wheel.
Incidentally the main function of the triple 42DCNF set up was to look good. Yes it did provide a little performance, but only at excessive (for a road car) RPM. For what my opinion is worth the 500 cfm two barrel Holley was a far better bet and I would have changed to that had I kept the machine. Finally I would warn that the transmission will not last more than 10K miles at much over 150 bhp and you can easily make this with the standard 38 DGAS Weber.
Barrie

Title: Re: Triple Weber 40 DCNF
Post by: administrator on November 30, 2018, 09:08:21

169 may be available for examination at Brooklands:

https://www.carandclassic.co.uk/car/C1060039

Title: Re: Triple Weber 40 DCNF
Post by: ME113 on December 03, 2018, 17:50:31

Back in my Scimitar days (mid-1980s!) the triple DCNF setup was mostly thought of as a way to ruin your fuel consumption for little gain.  The DCNFs are a "power" carb unlike the DFAV/DGAS the engines came with, if I remember correctly this means they don't have the part throttle/cruising jets the factory carbs have.

As the DCNFs are 42mm chokes and the standard carbs are either 40mm or 38mm, the air speed through the 6x42 chokes will be a lot lower compared to 2x40/38 chokes, hence Barrie finding they only came on song at high revs.