Fitting New 40 IDFs

[So Cal Mark]

no need to port my intake, it's sized properly to begin with. When we sell a system we include the synchronization linkage. The carbs work fine side by side.

[131lover]

Hi!
Mark:Is the intake manifold big enough for the IDF 44 as well without porting required?
Cheers
Alf

[So Cal Mark]

yes it will accomodate 44s

[Corydon]

I am about to order two new 40 IDF 70 (Made in Spain). I am not sure whether they should be with or without a choke. The dual barrel (register) carb that I have now has a choke and the car would not be able to start cold without it. Since the IDF is available without a choke I am not sure I have understood exactly how it works. It seems to me that a car would not be able to start cold without a choke function of some sort.

All you experts here - please educate me

[131]

Since the IDF is available without a choke I am not sure I have understood exactly how it works. It seems to me that a car would not be able to start cold without a choke function of some sort.

IDFs didn't come with a choke, they had a separate fuel enrichment circuit for cold starts. I've got 40IDF13/15 carbs on my 2 litre, no cold enrichment, it also has high compression and long duration cams, it's quite cantankerous to start on cold mornings. I have to start it and keep it running on the accelerator pump, it coughs, misses, spits back in the carbs and backfires until I get to the top of the street, about 300m. It runs OK after another Km or 2 and settles down to a loapy idle if I have to stop at the traffic lights. Much less dramatic in the afternoon on the return trip.

[Corydon]

Reading about 131's experiences with cold starting and engine with IDF carbs, I will be ordering my IDFs with a cold start device (choke). They cost 20% more but it will not be possible to retrofit a choke, according to the supplier. And if anything, the climate in Denmark is likely to be colder than that in Tasmania.

@131: Thank you for giving me a new word for my vocabulary. Cantankerous - a brilliant word! Dictionary says: "Often angry and annoyed, difficult or irritating to work with." I can easily picture how a cold IDF, with no cold start device, is to work with. And being a non-native English speaker - I like to collect new words.
And a piece of bonus info: Did you know that our crown princess is from Tasmania?

[Redline]

It's interesting that the knob in the cabin of my Coupe for the enrichment still shows symbolically a choke (butterfly), even though the IDF works differently (as described). The fuel enrichment circuit works quite well. I drive mine 3.5 seasons here in Switzerland, so it sees its fair share of starts on cold, damp mornings. It works well down to 0°C. I don't go out below that (no winter tires). The problem for me is more figuring out above which temperature you don't need it...

[sydh70]

error

[Corydon]

I am trying to work out how to connect my two new 40IDF 70s to the gas pedal. Mark mentioned that he uses a T-bracket mounted at the base of the carbs to hold a cable. Do any of you have descriptive photos of this set-up or something else that works?
My car is a 1974 and the stock linkage is a rotating rod with one end mounted in the firewall and the other end on a bracket on the left cam tower. The gas pedal-part in the engine bay has two arms. One short one with a ball-joint that connects to the stock linkage and a longer one that is used for the "hand-throttle-knob-cable". I am planning on using a cable from the carbs to this longer arm. Now I just need to work out the details on how to get this to work.

Any help and suggestions will be much appreciated, preferably with photos which are usually worth a thousand words.

[131]

And a piece of bonus info: Did you know that our crown princess is from Tasmania?

Our Mary went to the same school in Hobart that my 3 boys attended, my youngest is still there. Next time you're chatting with her you can ask her to teach you some Aussie slang.

[RoyBatty]

I am trying to work out how to connect my two new 40IDF 70s to the gas pedal. Mark mentioned that he uses a T-bracket mounted at the base of the carbs to hold a cable. Do any of you have descriptive photos of this set-up or something else that works?
My car is a 1974 and the stock linkage is a rotating rod with one end mounted in the firewall and the other end on a bracket on the left cam tower. The gas pedal-part in the engine bay has two arms. One short one with a ball-joint that connects to the stock linkage and a longer one that is used for the "hand-throttle-knob-cable". I am planning on using a cable from the carbs to this longer arm. Now I just need to work out the details on how to get this to work.

Any help and suggestions will be much appreciated, preferably with photos which are usually worth a thousand words.

Here's how I connected the throttle cable on my '75. I used the stock spool drum from the original carb on the back side of the rear carb. I had been advised by an "expert" that this can't work. But somehow, I have managed about 3K miles since I installed these carbs with no linkage problems.
Since you already have the bellcrank setup on your cam cover, you should be able to use a link rod from the bellcrank to the connector you see between the carbs in my picture.

[seabeelt]

Here is the setup on our 71:

Custom made bracket bolted to the carb and lever welded to the original throttle pedal


and cam shaft cover and linkge from or old 78 with new cable


I may modify the cam cover linkage base so that it rotates a little more toward thge fire wall. The cable is a little tight against the back air breather.

[Corydon]

Thank you for the inspiring suggestions to my linkage challenge.

@RoyBatty: Looks like you may have the same modern types of carbs that I have, 40 IDF 70. I am having trouble finding a good quality manifold, with a good fit, which has around 60 mm distance between the two middle studs for the carbs. It must have this space between the carbs, otherwise the modifications I will have to do on the carbs will be too much. Which manifold are you using?

[RoyBatty]

I purchased the setup shown from Auto Ricambi. It is the economy IDF setup shown on their website.
You can contact Csaba and Ramzi to find out where they source the manifold from.
Good luck.
Also, yes my setup arrived with the both the shafts linkages already modified due to the fit between the two carbs. It works great. And the linkage allows you to adjust the throttle shafts to synch the throttle plates if needed.

[Corydon]

I still haven't landed on a solution to my carb linkage problem. It seems like all the good suggestions here are on cars with a cable connecting the gas pedal to the carbs, as stock. Mine is a 1974 and it has rod linkage, which makes it more of a challenge. Has anyone on here tried to replace a rod linkage type gas pedal with a cable type gas pedal?