Carb issues

Discussion in 'The Venerable Q-Jet' started by hgiljr, May 24, 2020.

  1. hgiljr

    hgiljr Well-Known Member

    Good afternoon everyone. Hope all is well. I have been going somewhat crazy with carb issues. I have a QJ which was rebuilt by Ken over at everyday performance. After the motor was built and an attempt to tune, the mechanic said there was a vacuum leak and throttle shaft play. I sent back to carb to Ken and he did not find any vacuum leak or throttle shaft play. The calibration is at 73 jets 44b rods and CF secondary rods. The only thing he saw was that my throttle at idle was very open. To counter this, he installed idle bypass air by drilling two holes underside of the baseplate in order to allow for additional air into the engine at idle.

    Received the carb and have attempted to use several gaskets to see if that was the issue, but remains the same. The car is very hard to idle while cold having uneven idle where engine just idles and reving on its own. Once the car is warmed up, I attempt to tune via idle screws nothing occurs. I have closed the idle screws all the way and has no effect on the engine.

    As for gaskets, I have used the 1/4 thick FelPro 1905 (this is what was installed by scotty) as well as what was recommended by quadrajet parts. Currently gasket setup is

    1. Smiley face on intake
    2. Metal Shim
    3. Base Gasket part # 1714 from quadrajet parts on carb

    Same issue. I know back 2018, I was on the hunt for the proper gasket before engine was rebuilt, but for the life of me I cannot find what I purchased back then. I do recall when I bought the car, it had a 1/4 gasket, and I was able tune the idle. Suggestions? Recommendations? I am using the stock 1967 intake manifold.
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Put a vacuum gauge on the engine and see what it is pulling warmed up.
     
  3. mrolds69

    mrolds69 "The Cure"

    Both gaskets you used appear to be wrong for a stock 67 carb on a stock manifold. Quadrajetparts.com says it should be a 1705. I guess it depends on the carb you are using.
     
  4. hgiljr

    hgiljr Well-Known Member

    I was referring to the smily face as the 1705. i have that one at the base onto the intake. The main one that I had when I purchased the car is attached. With this one I was able to adjust the idle screws just fine. Just not sure what gasket this is. if you look at the primaries section it is a wider area. Tomorrow I am going to try 1705 and and metal gasket alone to see if that helps.
     

    Attached Files:

  5. mrolds69

    mrolds69 "The Cure"

    More Larry's area than mine, I'd agree you should put a vac gauge on it and see what it's doing, if possible.
     
  6. Cliff R

    Cliff R Well-Known Member

    What are the "specs" on the engine build?

    Once that you verify no internal vacuum leaks from the early intake set-up move to the carb. It may need custom tuning depending on the parameters of the engine.

    The carburetor part number would also help, is it the original unit or something else?........Cliff
     
  7. TORQUED455

    TORQUED455 Well-Known Member

    I admire your perseverance. You have had nothing but issues starting with the other engine’s oil leaks IIRC.
     
  8. 12lives

    12lives Engage! - Jean-Luc Picard

    Metal gasket should be against the manifold. It blocks the heat risers. I assume you have a stock manifold? Pictures of bottom of carb and manifold would help. Also, did Ken check the throttle plate for flatness?
     
  9. philbquick

    philbquick Founders Club Member

    Is your PCV valve and line open?
     
  10. hgiljr

    hgiljr Well-Known Member

    Hello everyone. Yes I have to continue, too much time and money spent and just seeing a car in the garage is frustrating. I finally got around to taking a look at many of the suggestions and also communicated with Larry offline. Here are pretty much all the answers:
    1. @Cliff R Engine is a 455, 30 over with 430 heads. 10.1. TA roller rockers, valves, pistons. Original intake and QJet. Large Cam, Mutha thumper (be gentle on the comments, it is what came with the original engine when I bought it and engine builder said it would be fine to continue with it). The carb part number was removed at some point before me. Appears to be the correct QJ for this year of car (1967 GS)
    2. QJet was rebuilt by Everyday Performance. It was also sent back recently and he said everything was fine for the engine specs.
    3. Today I did all sorts of tests with the gaskets. I redid the gasket setup as above. Same results
    4. I then removed all gaskets and shim and left the one main gasket between carb and intake. Same results where I am unable to tune the idle screws. All the way closed and you can see the irregular vacuum. You can see on the one gasket where it was pretty much soaked in fuel.
    5. I found the original 1/4 gasket that was on the car with the 400 engine. This time vacuum was not irregular, although it was a bit bouncy when testing. Once I opened the idle screws, the idle would increase drastically. Can't say how much RPMs as gauge does not work but you can hear it. Only way to bring down the idle was to close both idle screws completely.

    In speaking to @LARRY70GS he suggested to replace the intake with a performer or b4b. Currently at this stage in the game looking at pricing. I see @12lives above mentions to put the metal gasket against the manifold. This I did not try Greg over at quadrajet parts recommended to put shim between two gaskets. As for PCV valve question by @philbquick , not understanding correctly.

    So next step to look into intake, but any other recommendations appreciated.
     
  11. GS Spoken Here

    GS Spoken Here Well-Known Member

    What year carb?
     
  12. hgiljr

    hgiljr Well-Known Member

    From all the research it does appear to be from 67 but no numbers on the carb.
     
  13. 12lives

    12lives Engage! - Jean-Luc Picard

    It is not a shim. It is a metal plate to protect the gasket from the exhaust gas in the 400 heat riser. If the heat riser is blocked off you do not need it at all. Since you have a 455 there is no heat riser so ditch the metal plate.
    Have you sprayed anything around the base to check for a vacuum leak? If the Idle mixture screws are not working there is a vacuum leak or the carb has blockage in a circuit.
     
    Last edited: May 28, 2020
  14. hgiljr

    hgiljr Well-Known Member

    I did just that yesterday and only used the proper gasket, https://quadrajetparts.com/quadrajet-base-gasket-thick-buick-1966-p-98.html and same results where I am unable to tune the idle screws. Open or closed will make no difference. At the same time, idle is irregular as it goes up and down and you clearly see it on the vacuum gauge. Then I installed the gasket in the picture which I have no idea what part number it is as it came with the car when I purchased it and car is much steadier at idle with idle screws closed. Once you open them, idle will increase drastically unable to adjust unless fully closed.
     

    Attached Files:

  15. 12lives

    12lives Engage! - Jean-Luc Picard

    Can you post a picture of the bottom of the carb and the manifold intake?
     
    Last edited: May 28, 2020
  16. 12lives

    12lives Engage! - Jean-Luc Picard

    Last edited: May 30, 2020
  17. 12lives

    12lives Engage! - Jean-Luc Picard

    Since you have a 455 you need to get parts for it (year?) and forget 1967.
     
  18. hgiljr

    hgiljr Well-Known Member

    Pics attached. It's a Frankenstein motor. 1973 455 block, 430 heads (not sure what year as it came with the car) and 1967 400 intake. The circles on the carb where just done by Ken to allow more air, but didn't make a difference
     

    Attached Files:

  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Those holes will be blocked by the gasket
     
  20. 12lives

    12lives Engage! - Jean-Luc Picard

    oh, 400 intake. Based on the lack of burned paint your heat risers must be blocked. See below:

    [​IMG]
     

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