Qjet secondaries

Discussion in 'The Venerable Q-Jet' started by matt68gs400, Aug 2, 2016.

  1. matt68gs400

    matt68gs400 Well-Known Member

    Hi,

    I'm wondering if this stop isn't releasing at times. At the track, I'm getting times of 15 and then 17. My second half of the quarter sucks, with speed increases of 15 mph in the last 1/8 mile with a 455 and mild cam.

    My fuel pressure stays above 5.5 psi at WOT. I think I've effectively eliminated fuel supply issues as well as timing issues. I also installed a rebuilt distributor with 20* total mechanical. Initial at 12 and total at 32.


    [​IMG]

    I've checked the secondary air flaps and found that they aren't too tight and have just enough tension to close back up.

    Also, on the front choke off, when I pull the vacuum line off, I can see it release. The back one doesn't really move back out. If I pull it out manually, it will go back in when reconnected to the vacuum.

    Thoughts? Thanks!


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  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    That secondary lock out should not interfere with secondary opening as long as the choke stays open. All you need to do is have someone hold the gas pedal to the floor (engine off:grin:), then push the air valves in and make sure the secondary throttle blades are open all the way. If they aren't, you have the wrong cable or throttle bracket.
     
  3. 65wildcater

    65wildcater Trishieldasaurus Wrecks

    I don't take any chances with my Q jets, if the car is going to be raced at the track, I eliminate that lock out. It happened to me once, never again.
     
  4. carmantx

    carmantx Never Surrender

    Yes. Take that lockout arm off and toss it away. That may or may not be your problem, but get rid of it anyway.
     
  5. matt68gs400

    matt68gs400 Well-Known Member

  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    If that lock out is out of the way, then it has to be wrong cable, or wrong throttle bracket. Looks like there is a lot of slack at closed throttle. You are going to think you are driving another car when you fix that.
     
  7. matt68gs400

    matt68gs400 Well-Known Member

    Thank you! I can only imagine the difference it will make. So I can't assume anything with this car. But would the 400 have used the same bracket and cable as the 455?


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  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Mike Garrison has the throttle bracket. http://www.mrbuick.com/reproductionparts.html



    http://www.mrbuick.com/wpimages/wp4b5e10ae_05_06.jpg

    TA has the cable,

    http://www.taperformance.com/proddetail.asp?prod=TA_1260


    Not sure what is wrong with your set up. There are different cables, and different brackets.
     
  9. matt68gs400

    matt68gs400 Well-Known Member

    the cable appears to be about 21". Is it possible to tell if this bracket is correct just by pictures? It appears that the length is correct from bracket to carb linkage.

    [​IMG][​IMG]

    Here's the bracket sold at the Parts Place for a 71 455 engine. Different than what I have on now. (One sec, pics won't upload now)






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  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  11. matt68gs400

    matt68gs400 Well-Known Member


    Thanks a million Larry!
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    You can see the correct mounting holes for the stock bracket in your second picture.

    [​IMG]
     
  13. pbr400

    pbr400 68GS400

    I'm not sure what your bracket is from, but I agree with Larry that you have a lot of slack there. I just looked at mine; I have the small bracket like the one at the bottom of Mike's page, and my cable is straight parallel with the intake and valve cover. If peeking down the carburetor at WOT doesn't show you vertical flaps, you've found the problem.
    Patrick
     
  14. matt68gs400

    matt68gs400 Well-Known Member

    I appreciate everyone's help on this thread. I'm ordering a bracket from Mike at High Torque Racing. I'm going to wait on the cable and see how things fit first.

    Here's an interesting article on cables:

    http://www.buickperformanceclub.com/ThrottleCableComparison.htm

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  15. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Too long a cable with good length never a problem, build ur own cable with threaded and set screw cable stop. And toss the lock out , your smart enough not to floor it cold.
     
  16. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Olds bracket.
     
  17. matt68gs400

    matt68gs400 Well-Known Member

    Thanks guys. Lock out removed. I temporarily added 3 more washers to the cable by the pedal and that opens up the secondaries now. Very happy.

    I may start a post called "How to add 40 HP for 18 cents". ;)


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  18. matt68gs400

    matt68gs400 Well-Known Member

    New cable, bracket from Mike and had to bend the pedal lever about 1/2" and I now have secondaries that open fully. :)


    Thanks all!


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