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
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?
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
Does anyone have an more photos they could post. I'm interested in seeing how the throttle cable mechanism is set up.
Title: Re: Triple Weber 40 DCNF
Post by: B.P.Bird on October 12, 2018, 11:59:48
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.
Title: Re: Triple Weber 40 DCNF
Post by: administrator on November 30, 2018, 09:08:21
169 may be available for examination at Brooklands:

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.