Thanks Mate, I just sent him off a email then. I was hoping some people would know a formula with the different size bits, venturie size, chokes, jets etc. It's killing me not knowing what's the best way to go. it seems not very many people know much about the old twin carb setups anymore [V]

In the pinto building book by Des Hammill hasn't got exactly your setup in the starting point jetting but this is what it does have

Jetting for standard 2000 (40mm webers)

34mm chokes
135 mains
f11 Emulsion
190 air correctors
35 acc pump
40 f9 idle jets
4.5 aux venturis

timing 12 deg at idle 38 deg total, but it doesn't state 'all in' RPM

Jetting for modified 2000 (45mm webers)

38mm chokes
145mm mains
180 air correctors
f16 Emulsion tubes
40 accel pumps
45 f2 idle jets
4.5 aux venturi.

So somewhere in the middle would be the sensible starting point I think. As for the vacumm advance, there are two options for retaining it, and retaining it will be better if getting used on the street because basically the motor makes more power at higher manifold vacuum levels, meaning less throttle at cruise, less fuel being used. The standard vacuum port for the vacuum advance is drilled into the carburetor, sitting just behind the butterfly on the venturi side, so at idle there is no vacuum applied to it but at light throttle the butterfly edge rises above it exposing it to the manifold vacuum. The other method which is possible but i don't favour as much is to hook it to the manifold directly. this means the advance mech will see vacuum at idle and the idle speed will increase a fair amount, to correct it obviously you turn the idle speed down on the carbies, but this can cause the butterfly to be to far away from the transistion port which is after or part of the idle mixture port, this can result in a quick stutter when you get on the throttle from the closed throttle position (every braking corner for example). This isn't always the case, and to be honest I can't remember the porting arrangements in the 40's so i'm not sure how they will respond, Hope some of this dribble helps you!!!

quote:

---

Originally posted by kingcosworth

In the pinto building book by Des Hammill hasn't got exactly your setup in the starting point jetting but this is what it does have

Jetting for standard 2000 (40mm webers)

34mm chokes
135 mains
f11 Emulsion
190 air correctors
35 acc pump
40 f9 idle jets
4.5 aux venturis

timing 12 deg at idle 38 deg total, but it doesn't state 'all in' RPM

Jetting for modified 2000 (45mm webers)

38mm chokes
145mm mains
180 air correctors
f16 Emulsion tubes
40 accel pumps
45 f2 idle jets
4.5 aux venturi.

So somewhere in the middle would be the sensible starting point I think. As for the vacumm advance, there are two options for retaining it, and retaining it will be better if getting used on the street because basically the motor makes more power at higher manifold vacuum levels, meaning less throttle at cruise, less fuel being used. The standard vacuum port for the vacuum advance is drilled into the carburetor, sitting just behind the butterfly on the venturi side, so at idle there is no vacuum applied to it but at light throttle the butterfly edge rises above it exposing it to the manifold vacuum. The other method which is possible but i don't favour as much is to hook it to the manifold directly. this means the advance mech will see vacuum at idle and the idle speed will increase a fair amount, to correct it obviously you turn the idle speed down on the carbies, but this can cause the butterfly to be to far away from the transistion port which is after or part of the idle mixture port, this can result in a quick stutter when you get on the throttle from the closed throttle position (every braking corner for example). This isn't always the case, and to be honest I can't remember the porting arrangements in the 40's so i'm not sure how they will respond, Hope some of this dribble helps you!!!

---

Thanks Mate, Yeah it does. It seems to me it would just be better to go up to the 45's. The guy from Euro carb said with my setup and what i want to do he said im better off going up to twin 45's

So i'll be taking off the twin 40's soon enough and smacking on some 45's! Thanks for the info though King! It helps to know anything about twins!

Hi Guys,

Just wondering if anyone has hit this problem before with twin carbs before, my aux venturies spit the dummy and fall out of the carb into my filter boxes and they are fitting in ok but are loose inside the carb, one venturie the metal spring on the side has fallen out completly and now will slide in but not stay in. I checked all the others and they all click in but are easily able to slide out. Ive got a funny feeling the venturies in there are too small or im missing somthing.

Maybe those trumpets that go on the carbs help hold them in more, it seems to look that way anyway.

I took a photo of where the metal spring fell out, can you fix these or just buy new one??



Also, when changing aux venturi sizes do you have to change the main venturi aswell? or is it just the aux size that changes?

I've recieved a few goodies in the last couple of weeks and forgot to post new photos. I've decided to get my car dynoed also and get John Collins (Newcastle Dynoer) to sort out my jet's venturies, chokes etc. Hes the expert lol.

New Momo Wheel


New Momo Shifter



New Strut Brace

good to see you finally mount that catch can

Just thought id post some pics of the car when i first bought it. Once everything is completed on it ill post the most recent pics

Very nice early shots, i like the new steering wheel as well.

You will feel the difference in the front end, with a strut brace fitted.

Ok well i mounted my new linkage today and also put the new cam vernier on and a belt change. the engine's timing is out by a bit so i must have turned the engine a tooth or so. I took some pics and got some video footage aswell.









HAD TO DRILL HOLES FOR NEW THROTTLE


SHINEY RAM TUBES


NEW QUICK RACK WITH RACK MOUNTS (I know the lock nuts haven't been bend yet [:p])





Now this is the vid of me first starting it, bit of backfire lol [88]
http://www.youtube.com/watch?v=dyNaZ26Rk9o

This is after it's been warmed up a bit, it's out of tune and sounds like it's flooding.
http://www.youtube.com/watch?v=zPM-uTmIKGQ

Had a test drive, you can hear it choking up
http://www.youtube.com/watch?v=f0gr5duaH3o

I took it around the block for a spin and one it opened up it was ok, just down low it's a dog. Also my new quickshift wouldn't find 1st gear after a little bit of driving [B)]

To find 1st, just don't press down on the lever and look for reverse.
They are good apart from the noise they make down the M1.