Thermoquad low vacuum readings

Fuel and Air Systems

  1. rumblefish360

    rumblefish360 So close, yet so far away

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    Oh yea!
     
  2. midnight340

    midnight340 FABO Gold Member FABO Gold Member

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    My jets are really stuck in the “73 6518 body, I have a spare “73 6322 body that I think is the same in case I can’t free them up.
     
  3. rumblefish360

    rumblefish360 So close, yet so far away

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    Let them sit in a pool of Penetrating oil.
     
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    • midnight340

      midnight340 FABO Gold Member FABO Gold Member

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      OK, I tried a spray, but I can let them soak when I pull it apart. :)

      Someone has reasonably priced Carter TQ NOS jets on eBay right now, in case anyone is looking. I went ahead and ordered a set of .104's just to have on hand.
       
    • Dana

      Dana FABO Vendor FABO Vendor

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      If it is cruising nice and lean without a surge, why would you want to jet up? Just stiffen the spring and let it enrich quicker. Your numbers look great. Edelbrock guys would kill for those numbers.
       
    • rumblefish360

      rumblefish360 So close, yet so far away

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      FWIW, I’d tighten up the door a 1/2 turn and see what that grabs you. The larger jets would be better on the power return. Enrichment would be a good idea IMO. The carb will only enrichen when the warmer weather returns. He is VERY lean now.

      Leanburn engines ran up to and around a 17-1. He doesn’t need to push it.
       
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      • Dana

        Dana FABO Vendor FABO Vendor

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        I just meant that the spring needs more force, to overcome the vacuum sooner when he pushes his foot down at cruise. Sometimes what I mean and what I say don’t come out the same.
         
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        • rumblefish360

          rumblefish360 So close, yet so far away

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          LMAO! I hear ya!
          That and people ... ehhhh, never mind....
          :lol:
           
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          • midnight340

            midnight340 FABO Gold Member FABO Gold Member

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            You’re not alone in that!!! LOL
            I’ll start with a bit more spring, but I’ve got the jets and this motor seems to really like it’s fuel.
            As a recent Edelbrock to TQ convert I’m pretty happy with where this is going!!!
             
          • rumblefish360

            rumblefish360 So close, yet so far away

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            I’ve always said there an excellent street, street/strip carb. Followed by the AVS.
            D5E3F8CB-AC63-4480-8543-344C84BEEDB6.jpeg 73F5595C-55F1-4770-97A1-8A57C0338777.jpeg 808E2414-3887-484B-8D00-17833CBDFBEE.jpeg
            LOL! I should try this for fun!

            9CC8E1A6-2174-405F-BD68-745084AB36FF.jpeg
             
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            • midnight340

              midnight340 FABO Gold Member FABO Gold Member

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              YEAH!!! Never ever ran a tunnel ram, but always wanted to... !!!
              2XTQ=:lol:

              9cc8e1a6-2174-405f-bd68-745084ab36ff-jpeg.jpg
               
            • pishta

              pishta I know I'm right....

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              There is a dual TQ pic in the offy catalog. Does anyone remember pics/story of a Navarro quad 4bbl intake tested by a Police dept? Yup, 4X4bbls!
               
            • rumblefish360

              rumblefish360 So close, yet so far away

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              This thing ya mean.
              76CC9B89-D971-4302-AECD-FD83623B8BB9.jpeg
               
            • midnight340

              midnight340 FABO Gold Member FABO Gold Member

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              I never checked what TQ adjuster tools were supposed to look like, but here’s what I came up with. Pretty easy to make, easy to hold and I wasn’t using these fittings anyway.
              83BCE60B-34F0-4FFF-8DB6-FA132C6C7121.jpeg
               
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              • Dana

                Dana FABO Vendor FABO Vendor

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                :thumbsup:That’s what I’m talkin bout.
                 
              • rumblefish360

                rumblefish360 So close, yet so far away

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                Hey! Nicely inventive.
                 
              • midnight340

                midnight340 FABO Gold Member FABO Gold Member

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                As a refresh here, I'm trying to dial in the freshly rebuilt TQ 6518. Motor is a 9:1 340, cam is a Lunati 235/243 @ .050, .526/.546 lift solid.

                So today I put 4 turns on the primary rod adjustment (from 2-1/2), and increased the air door spring preload from 1-1/2 turns to 2-1/2. No change in primary rod spring yet, and no jet changes. (As I said, I have .031" nozzles, and .098/.137 jets, )

                Idle is still about good at 14.9
                Steady cruise at 2200 and up at 15.7

                The change in rods and spring preload, changed my mid-rpm light-throttle readings from 17.5 to closer to 16.5 or so. I assume this is from raising the rods, and I probably still need to jet up from .098 to .101 (or .104 ???)

                Here's my question, the WOT reading was 12 to 12.5 which I was fine with. But now I'm quite a bit richer somewhere around 10-10.5.
                IS THIS WOT A/F CHANGE LIKELY FROM THE SLIGHTLY RICHER PRIMARIES, OR FROM THE AIR DOOR ADJUSTMENT
                ???? Or both??
                 
              • rumblefish360

                rumblefish360 So close, yet so far away

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                Both.

                When you tightened up the secondary door, it comes in later and slower. That will enrich the mix. The door also may not be fully opening. 2-1/2 turns from a dead handing door is the suggested starting point.

                The carbs secondary door should open up as soon as possible or as quickly as the engine can handle it without issue.
                 
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                • rumblefish360

                  rumblefish360 So close, yet so far away

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                  Mystery double posting.... move along....
                   
                • Dana

                  Dana FABO Vendor FABO Vendor

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                  Did you ever get a lean surge before you raised the rod tree??
                   
                • midnight340

                  midnight340 FABO Gold Member FABO Gold Member

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                  OK, not sure what "dead handing" is... Anyway, I can likely go back closer where I was, as it worked pretty well. Once or twice it would stumble/bog for a second when I really snapped the throttle down while cruising. Originally I had tightened the spring until the door just came up to horizontal, then 1-1/2 turns.

                  I'm trying to figure out what does what... So I loosen the door till it bogs when I stomp it, then tighten just a bit?

                  No, don't believe so. I raised the tree thinking it might help the mid rpm part-throttle application lean symptom. I have jets on order, and and as Rob said earlier, that indicates that the primary jets are too small.
                   
                • Dana

                  Dana FABO Vendor FABO Vendor

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                  Forget about the secondary air door for now. The TENSION will only effect a/f for a moment. Remember lean makes the most power, and is the most responsive. When a motor gets tuned to the max on the dyno, most of the time the carb is so lean it won't run on the street.( At least won't have good manners. )Forget the jetting for now. You have great a/f #'s already. You just need to work on the metering rod timing. IMO
                   
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                  • rumblefish360

                    rumblefish360 So close, yet so far away

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                    Dead “Hanging”

                    Experiment with the air door tension settings. From a dead stop or part throttle, the engine should not stumble. If it does, tighten the door until it stops stumbling.
                     
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                    • midnight340

                      midnight340 FABO Gold Member FABO Gold Member

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                      I think I'm there. Running pretty sweet. Much stronger response than the Edelbrock when I stomp it, and clearly tends to run leaner when the power is not needed. Have to wait for spring to put it on the track.

                      Went back to 2-1/2 turns up for the rods, and changed the spring to a hardware store spring that I lucked into, maybe? a bit stronger than stock but longer by 1/4". The air door I set at 1-3/4 turns from just coming up level. No choke so the motor has to be fully warmed for no hesitation when I snap the pedal down, but once warm no issues at all.

                      Have all my numbers pretty close to where I want them. Idle mix at 14.8 or so, then 15.8 to 16 when just cruising along, but drops to about 11.8-12 WOT. Still goes way lean with steady light throttle applied (17.5/18:1) but really no problem really, as it's only a short term situation. Now it's time for a new set of NGK's to check after driving for a while.

                      Thanks for all the help getting through this!!! Now I have to come up with something new to obsess over!!!!:lol:
                       
                    • rumblefish360

                      rumblefish360 So close, yet so far away

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                      When does it get super lean?
                       
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