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Edelbrock dual quad progressive linkage fix

Discussion in 'The Hokey Ass Message Board' started by tjet, Oct 14, 2011.

  1. tjet
    Joined:
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    Northeast USA

    tjet
    ALLIANCE MEMBER
    1. Early Hemi Tech

    This is a heads up if you are using that linkage kit. I've been trying to set up my dual quad. If I set both the carbs for WOT, the rear carb would stop before idle stop when the throttle was released. If I setup idle, the rear carb would not reach WOT - unless I ran the threaded rod end almost completely out (not safe). That seemed to work, but the lower rod would come out of the forward block. The rod coming out of the block may cause a jammed throttle.

    I finally realized that the rods are too short, and it would not allow the rear carb linkage to travel fully

    Now this may not be the case on your motor. I have an old Edelbrock O-65 Olds intake, & the carb centers are 6-7/16" apart. The carbs are Carter Competition series, 500 cfm. The rear carb # is 4758, & the front is 4761.

    I ordered the following from McMaster-Carr
    http://www.mcmaster.com/

    1 ea Male-Female Threaded Hex s/s standoff, 3/8" long, 10-32, # 91075A171
    http://www.mcmaster.com/#91075a171/=ehnyus

    1 ea Male-Female Threaded Hex s/s standoff, 1/2" long, 10-32, # 91075A172
    http://www.mcmaster.com/#91075a172/=ehnz88

    I installed the 1/2" standoff on the rear carb rod, & the 3/8" standoff on the front carb rod. This simple fix allows full travel of the rear carb linkage. Another plus is the it gives the rod a hex surface, so you can sung up the rod-end jamb nut without holding the rod with pliers. These hex nuts allow you to thread the rod ends in further. I have mine in all the way. I think if I did it again, the 5/8" standoff would be better for the rear.

    I also went ahead and upgraded the rod ends, but it's not required. The rod ends I ordered are superior to the ones in the kit. They are p/n 6072K16

    http://www.mcmaster.com/#6072k16/=ehnyh8

    Anyway, works like it's supposed to now :D $20 total

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    Last edited: Oct 14, 2011
  2. oldschool66
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    oldschool66 Member

    Great tech info, thanks. This is the best part of the H.A.M.B., sharing problem solving ideas.
  3. oj
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    Berryville, Virginia

    oj Member

    Nice work, looks like an extra hole drilled into the accelerator pump arm on each carb. You might move your linkage arm to those holes if you have a stumble.
  4. tjet
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    tjet
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    1. Early Hemi Tech

    Thanks, I will keep that in mind when I start tuning it
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  5. stlouisgasser
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    Sep 4, 2005
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    St. Louis, MO.

    stlouisgasser Member

    Interesting stuff. Thanx for sharing and listing the part #'s. I have the same progressive linkage kit for the Killer Biscuit so I saved this thread just in case of any problems. Thanks again for posting!
  6. cuznbrucie
    Joined:
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    South Jersey Shore

    cuznbrucie Member

    Great tech piece!.......I used the same type of rod ends with the really nice swivel action that never binds.......but I didn't realize that maybe I ought to look into those standoffs.......so far I have not had any trouble with my dual quad setup with Edelbrock carbs on an Edelbrock intake manifold I think it's a C26?

    Appreciate your sharing those ideas with us.....

    CB
  7. tjet
    Joined:
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    tjet
    ALLIANCE MEMBER
    1. Early Hemi Tech

    Thanks for the complements :D

    I think I'm going to order the 5/8" long standoff for the bottom, and put the 1/2" on the top rod ISO the 3/8". I will also cut down the threaded section of the rod ends that screw into the standoffs. I'll probably leave around 1/8" threads showing on each one once the jam nuts are torqued so they match.

    It looks a little funky if the rod end is too far out with too many threads exposed - like in my installed pic.

    I will post again once I modify it
  8. tjet
    Joined:
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    tjet
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    1. Early Hemi Tech

    I finished the linkage. I ended up using the 5/8" long standoff on the lower rod, & a 1/2" one on the upper rod. I cut 1/8" off the forward rod-end thread at the 1/2" standoff so they both match.

    I also upgraded the springs & mounts. The Edelbrock kit had a couple of cheap mis-matched springs in it. I got a pair of s/s precision springs. As for the mounts, I installed a couple of studs in place of intake bolts. I put thread reducers on them, & threaded in spring pull studs.

    The first pic is idle, then part-throttle, then WOT.

    Now I can start building the s/s fuel lines

    Attached Files:

  9. Don's Hot Rods
    Joined:
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    florida

    Don's Hot Rods Member

    I've been staring at your picture to try to figure out why you ran into this problem and I think maybe it is because of the holes in the arms you chose to use. We have two of our cars running the exact same linkage and carbs as you do, and the Edelbrock linkage virtually went right on out of the box.

    Here is the one on my Sons T bucket.

    [​IMG]

    And here is the one on my 27.

    [​IMG]



    If you notice, our stops are located a lot closer together than yours are, and the linkage goes a lot higher on the front arm. Not saying yours is wrong or anything, just different.

    I just checked my 27 for WOT on both carbs yesterday because I am going to race it at the BP Drags, and both hit WOT at the same time.

    Don
    Last edited: Oct 19, 2011
  10. boutlaw
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    flowood, ms

    boutlaw
    ALLIANCE MEMBER

    My 66 OT MUstang is the same as Don's in the previous post, and works great. Thanks for posting the tech regardless, especially the P/N's, however, the linkage angle on the front carb seems a bit exaggerated, but if it works without binding and hits WOT, you're good to go.

    Brad
  11. 72Hondo
    Joined:
    Jun 9, 2012
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    Location:
    TX

    72Hondo Member

    I relaize this is an old thread.

    I installed The eddie porgressive linkage and also found the rods to be way too short. My carbs seems to sapced further than anyone here. I think the stand offs will help me increase the rod length. thanks for that

    My problem is first time i went to try it out to see if it would hold up, it did not. The linkage pulled from the brass bearing block and the aluminum collar was lost, so im trying to figure a way to fix that.


    [​IMG]
  12. tjet
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    tjet
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    1. Early Hemi Tech

    Your rod ends are pretty far out. In your case, the standoff's should work pretty good. They are cheap enough that you can buy a few different lengths to see what will work

    I need to get another progressive kit later on. I won't need the aluminum collar. You can have it
  13. Larry T
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    north central Texas

    Larry T Member

    So why does Edelbrock say to set the linkage running down hill? I've had good luck setting them up with the rear linkage on top and everything parallel.

    Attached Files:

  14. tjet
    Joined:
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    tjet
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    1. Early Hemi Tech

    That would work too. It all depends on how far out the progressive linkage is away from the pivot point on the carb linkage. The rear carb linkage should travel a little farther than the front carb in a progressive setup. The way to do that is to move that carbs' linkage farther from the fulcrum point, which add more arm to that carb - rear primary carb gets more "arm", front carb less
  15. UNCLECHET
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    Wichita, Ks

    UNCLECHET Member

    Great post! I bought a car with this set up and I never have liked the way it looks from a functional point of view. My return springs are very flakey. I've been working on other parts of the car but this winter I'm going to make sure I'm getting WOT and rework the return spring setup. Your post has really helped me with some ideas. Thanks.
  16. tjet
    Joined:
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    tjet
    ALLIANCE MEMBER
    1. Early Hemi Tech

    Thanks. I didn't like the cheap springs either that came with the kit. These are the better springs I got. I ordered them about .25" shorter than the span so they would stay tight. They are the Ultra-Precision Extension Springs

    http://www.mcmaster.com/#extension-springs/=j1gea1

    & the spring "anchor studs"

    http://www.mcmaster.com/#extension-springs/=j1gnxe

    Which thread into these...

    http://www.mcmaster.com/#cadinlnord/98434a210/=j1gfsv

    Which go into studs I used in place of 2 intake bolts

    http://www.mcmaster.com/#catalog/118/3169/=j1ggh7


    Here is my dual quad fuel line build link for reference

    http://www.jalopyjournal.com/forum/showthread.php?t=629167
    Last edited: Aug 28, 2012
  17. 72Hondo
    Joined:
    Jun 9, 2012
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    Location:
    TX

    72Hondo Member

    The standoff's did help greatly and I also went with a longer rod. I picked up another collar. I have yet to test it though...

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