Looking at a 7026250

[Mudsport96]

So I got to looking at one of the carbs given to me the other day and was wondering what this lever is




since there is no vacuum brake or linkage on this carb,is this spring loaded to have a similar  effect?

[carmantx]

That is a 1966 Oldsmobile Quadrajet.  The first year for production.  Many things about that Quadrajet are different and we're soon replaced with upgraded designs.
That arm is the secondary dampener, I believe it is called.  Sort of the pull off for the 66 Quadrajet.  I have one of those on my bench now I am working on.

[Ethan1]

 From Lars:

 Some very early Q-jets used a small damping piston in the air horn that extended into the main body to dampen the air valve opening, which reduced oscillations when the air valve opened.

[Mudsport96]

Cool, thank you guys for the info, probably going to open it up tonight after work and see how it looks inside.

[carmantx]

It will look different on inside than most also!

[Mudsport96]

Anybody happen to know what purpose this serves? havent seen it on newer carbs, so i am thinking it was not really needed...

[Mudsport96]

[Mudsport96]

Well, apparently the photobucket is down so my pictures are not visible... Anyway, what I am seeing under the passenger side secondary flap, is tab or deflector at close to a 30 degree angle about half an inch below the fuel discharge tube. Antone come across this before?

[Ethan1]

Well, apparently the photobucket is down so my pictures are not visible... Anyway, what I am seeing under the passenger side secondary flap, is tab or deflector at close to a 30 degree angle about half an inch below the fuel discharge tube. Antone come across this before?

 I saw your photos last night and just didn't have time to reply. Most carbs of that year (Chevrolet, Pontiac, Oldsmobile, etc.) had that "tang" on there. Not sure of purpose. Maybe to deflect extra velocity air into the certain part of the engine? Maybe a baffle?

[Mudsport96]

Awesome, thanks for the answer. I tried looking on the page with all the part numbers you posted, but didn't see it. Was just curious why it was dropped as an idea.

[Ethan1]

 Yeah, for some reason, Rochester didn't put everything on the parts list. It does have a part number. Surely, you would think it would be on that list. As for dropping the idea, I believe in the late 60s, early 70s, there was something similar done. Except on the divider baffle. Let see if I can find a photo. Same purpose, I believe it was to deflect more velocity air in parts of the engine. I could be mistaken, but I am pretty sure.

 EDIT: Here is this: http://cliffshighperformance.dreamhosters.com/simplemachinesforum/index.php?topic=1558.msg7474#msg7474

 The photo was from an '85 Qjet, but there was another year Qjet with the same kind of notch on the secondary flap.

[Ethan1]

 Won't let me upload anymore attachments and PB isn't working, so you are going to have to go to Google.

 But, the 1985 Qjet divider baffle is on there with the "notch" or "tang".

 https://www.google.com/search?q=qjet+divider+baffle+tang&biw=1366&bih=659&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiKi_H6oZDQAhXGeSYKHY_nD3cQ_AUIBygC

 

[Mudsport96]

Yes that's the flap on mine.. And i saw a post with the box on the divider, its probably the same concept. The whole carb will probably just go on my shelf. I don't really need to use a 66 carb as I have several others to play with. It can just wait around for someone that needs a complete carb for a 66 Tornado lol.

[carmantx]

Looking at all the years of Quadrajets, it is interesting to see the things used for a year or two and dropped.  I think I heard that flap on the air valve made no difference in performance and not needed. 

[Ethan1]

Looking at all the years of Quadrajets, it is interesting to see the things used for a year or two and dropped.  I think I heard that flap on the air valve made no difference in performance and not needed.

 I heard that, too, but I wonder why Rochester kept trying to come up with an idea to do that. Could've there been an easier way? Maybe back then, the answer and technology they had, would be NO. Interestingly enough, I have seen 3 different variations of this "modification" by Rochester. Hmmmm.