Carburetor Question - Is this a good call?

Fuel and Air Systems

  1. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    OK. Lets start at the top and fix this thing.
    > Model 4160 is a very general model identification. The exact model (in non-Holley speak) is the "List number" (Holley speak) stamped on the choke tower. It's probably an 1850-? but maybe not. Find it, post it up.

    > There's two ways to approach this. Some combination will work for you.
    a. Follow a set of directions, procedures and settings. This worked fine with factory stuff, and sometimes works OK with aftermarket.
    b. Understanding how it works and then figuring out what changes make sense.
    The best intro to how Holley carburetors work is probably the first chapters of Urich & Fisher's Holley Carburetors and Manifolds. Buy a used older edition - you don't need Holleys promotional of their EFI etc.
    On-line, Chrysler's Master Tech series is a good option even though not Holley specific.
    Follow the link and see 1966 "Carburetor Fundementals", or the slightly revised version in 1970 (adds smog carb and Holley power valve info).

    If you had good performance before, then the model is not the issue. Something has changed.

    Please check. Although I don't think this is it, it is important. Write down the timing and rpm. Make sure it (timing) advances with rpm once its over 650 or 700 rpm. Reconnect the vac advance.

    Not a mistake at all. There's really nothing to 'rebuild' 99.5% of the time. Its just a matter of cleaning and installing new gaskets; then checking the dry settings. Send it out when things are broken, it needs refinishing, and/or is so dirty or corroded it needs a ultrasonic cleaner and other measures.

    Yes. Please check this.
    I agree with Willrun. Overfilling the bowl is most likely culprit.

    If you can, after the engine is stopped, look down the carb and see if you can observe fuel coming out of the vents, or the boosters.

    If it is, there are only two possible causes. Inlet system is letting in fuel when it shouldn't, or the fuel pressure is higher than it should be.
    If the fuel pump and lines haven't changed, then start where you should alsways start in setting up the carb - float levels.

    However there are other ways excess fuel can end up in the intake manifold.
    One is incorrect or failed power valve gasket, or damaged power valve.

    There's others, but these two are where to start.

    While the bowl is off, look at the acclerator pump check valve and diaphram.

    Uh yes but you've changed carbs, so all bets are off. Something may be different with the replacement.

    Jets could be removed and it still should run fine up to 40 or 50 mph.
    If the choke has been fully opening, and the timing is working, the adjustment sequence should be float/fuel level, then idle throttle position, then idle mix. Only after those are good, adjustments can be made forthe higher speed (jets) and for accelerator pump (rapid throttle openings from near closed throttle).

    The last bit almost sounds like vapor lock or running low of fuel in the bowls or in the accelerator pump... I say that because you close the throttle and the engine returns to life.

    The power valve opens an enrichment circuit for full power situations. It only opens when close to wide throttle and engine is under heavy load or acceleration. Engines run somewhat rich at idle but then leaner off idle and under part acceleration. But near maximum accleration they need a richer mixture again. See the book and/or the master technician pamphlets suggested above.
     
    Last edited: Jan 3, 2020
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    • 65Val

      65Val Average Length Member

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      Just to be "that guy"......original 273 Commando/Charger's used 500 AFB's, not AVS's.
       
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      • pishta

        pishta I know I'm right....

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        Holley gaskets pucker over time. You can rebuild it and run it and then put it on a shelf for 5 years and the block gaskets will look like hourglasses when you pull them . Get the good blue gaskets and put chap-stick on them prior to install. There aint a gasket under the waterline of a Carter. Jets and rods are a cinch to change: just a screwdriver..dont even have to drain the carb. Drives Rich gets a fatter rod, lean gets a thinner one. Takes about 2 minutes to change a rod in a carter, you can almost do it with the car idling. Idle is screws up front. 65 273/4 didnt get an AVS, it was an AFB, Not invented yet. primary and secondary jet are listed. Rods may have been .068 X .050 from a 3447 as the 3447 is a legal replacement carb.

        DODGE
        1965-67
        DART 273”
        7043
        4119S, 4119SA
        AFB

        .089
        .073

        DODGE
        1966
        DART W/O C.A.P. 273” AT
        7045
        4120S, 4120SA
        AFB

        .089


        DODGE
        1967
        DART W/O C.A.P. 273” AT
        7045
        4120S, 4120SA
        AFB

        .089


        DODGE
        1965-67
        DART 273”
        7047
        4121S, 4121SA
        AFB

        .089
        .073

        DODGE
        1965-67
        DART 273”
        7049
        4122S, 4122SA
        AFB

        .089
        .073
         
      • pishta

        pishta I know I'm right....

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        Hey, I was that guy too... you just beat me to it! :icon_fU:
        Also technically they were 470 CFM's....
         
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        • crashcaptn

          crashcaptn 1965 Dodge Dart GT

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          Hey all,

          So i took the carb off to check out the jets and get some info for the thread and to do my own investigations.. theres a riser / adapter plate for the holley to carter-type bolt holes on the intake manifold and the gasket stuck to the manifold which showed me the following...

          IMG_0828-1.JPG IMG_0833.JPG IMG_0834.JPG

          So i peeled that off and cleaned it up with a wire wheel and put it all to bed. My first step is to find a new adaptor plate (any links all?) and get it on there... i cant believe its been like this forever
           
        • Treblig

          Treblig Well-Known Member

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          I don't think there's any way the motor would run right with all that mis-matched junk under the carb????????
           
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          • crashcaptn

            crashcaptn 1965 Dodge Dart GT

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            ya.. things are starting to make some sense all of a sudden. I'm currently combing the internet for an adaptor plate that'll bolt to my intake and allow for a Holley carburetor
             
          • yellow rose

            yellow rose Doctor of Thinkology.

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            Why are you running that adapter plate? I'm totally lost. None of this makes the least bit of sense.

            If you have a square bore carb (and I think you do but some better pictures or the LIST number off the choke horn would help a bunch, as would what spark plug you have) and a square bore intake manifold, why in the blue oatmeal hell is that adapter on there???

            If you have a square bore intake manifold, and a spread bore carb, take the carb, and the adapter and get yourself a BFH and beat the living shit out of both of them so some other poor sucker doesn't end up with that junk and then throw that crap in a river and let the fishes use it for a playground.

            This thread is never going to help you if we don't know what you have. And from the looks of it, some of it is straight junk.
             
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            • fishmens67

              fishmens67 Well-Known Member

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              OH MY !!
               
            • crashcaptn

              crashcaptn 1965 Dodge Dart GT

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              I’ve got the adapter plate because I’m running the stock intake that originally had a Carter and I’ve got my Holley on it. Not the same bolt patterns. When I got the car in 2004 this is the setup it had. That plate and the Holley. Whoever bought the plate before me didn’t do a good job! And whenever I would rebuild or take the carb off I’d never remove the plate. Till now. I was shocked how badly that is done.

              I’ll get details on the carb here in 30-45 mins and the plugs as stated earlier are NGK. I’ll get info on them, too. But I agree. I have no idea why someone would run this as a setup. NOW if I don’t need that adaptor that would be great.. but I don’t believe a Holley will bolt directly right up.

              yup. Agreed.
               
            • yellow rose

              yellow rose Doctor of Thinkology.

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              From the above picture, that intake looks like it takes a square bore carb, like most Holley and Carter/Edelbrock carbs.

              That adapter if for adapting a Thermoquad or Quadrajet to a square bore manifold.

              Even if the secondary bores on the intake are SLIGHTLY bigger than the primary bores, that is still considered a square bore manifold and the adapter isn't needed.
               
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              • Johnny Dart

                Johnny Dart Well-Known Member

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                Who's on board ?

                40c58b6c19784098b61bdcb623690764.jpg

                IMG_20151108_084516472_HDR.jpg
                 
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                • yellow rose

                  yellow rose Doctor of Thinkology.

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                • crashcaptn

                  crashcaptn 1965 Dodge Dart GT

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                  After some research thats what it seems - it looks like whoever put this on used exactly that, a Quadrajet adaptor. I took some pics of it just now when fetching the horn #'s.

                  IMG_0836.JPG

                  IMG_0837.JPG

                  If you look at the first picture, thats the bolt pattern for the intake manifold. The outside studs are what allows the holley to bolt on. Second picture is what was against my manifold which is absolutely incorrect. I need square bore to square bore adaptor plate. My Holley will not bolt to my intake without it.

                  The horn numbers are 80457-6 and 2706 under that.

                  The NGK plugs are the G-Power platinum plugs stock "GR4GP 2763"
                   
                • 65Val

                  65Val Average Length Member

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                  That intake is the early Carter bolt pattern. A newer Carter/Edelbrock won't bolt directly to it until you drill the 2 narrow bolt holes in the baseplate. @Johnny Dart 's pic shows the narrow and wide pattern on an AFB...
                  . img_20151108_084516472_hdr-jpg.jpg

                  A Holley will require an adapter plate, but not the one you have.
                  1351935_R_3a093461-9bab-4f2b-88a2-80f5d326de4a.jpg
                   
                • yellow rose

                  yellow rose Doctor of Thinkology.

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                  There you go OP. That's an adapter you can use. That other thing...who knows how it ended up on there. But it just ain't right.
                   
                • harrisonm

                  harrisonm Well-Known Member

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                  In my humble opinion, unless you are competent at carb rebuilding, I would buy a new one. They are not that expensive, and Edelbrock carbs run great out of the box and are easy to tune. I realize carbs are not terribly hard to rebuild, but if you aren't comfortable doing it, buy a new one. Also, I would think twice about buying a used one unless you totally trust the seller.
                   
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                  • crashcaptn

                    crashcaptn 1965 Dodge Dart GT

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                    Agreed agreed fully - in the river it goes. Not kidding guys i've been running this car with that for years.. incredible. The primaries had NO breathing whatsoever.. no wonder it acted like an asshole. I'm hunting the internet for that adaptor now and will be reporting back.

                    Thanks for taking this arduous and irritating adventure with me, all.
                     
                  • yellow rose

                    yellow rose Doctor of Thinkology.

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                    So the carb looks like an updated 1850 although from the little bit of data on line, I can't see what the difference would be between your carb and an 1850. Both are essentially emissions carbs so the tune up should be very close for what you are doing, once you get that wacky adapter off there.

                    Now, on to the plugs to see what they are.
                     
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                    • 65Val

                      65Val Average Length Member

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                      Glad we could get to the bottom of it with you. That's what this site is all about...helping each other!
                       
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                      • crashcaptn

                        crashcaptn 1965 Dodge Dart GT

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                        heh. adaptor will never go back on ever again.. it'll make good wall art.

                        Thanks! Almost there for sure. And once i find and buy and install the new adaptor i'll do plugs and wires and a new fuel filter and update here
                         
                      • crashcaptn

                        crashcaptn 1965 Dodge Dart GT

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                      • 65Val

                        65Val Average Length Member

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                        Yup...that'll work.
                         
                      • crashcaptn

                        crashcaptn 1965 Dodge Dart GT

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                        neato thanks. this is a stupid problem to have.
                         
                      • yellow rose

                        yellow rose Doctor of Thinkology.

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                        Damn NGK numbers...from what I can find (NGK sent me two power sports catalogue instead of an automotive catalog...I should be getting the automotive catalog in a week or two) your plug crosses to a Champion RN11YC. If so, that may be a bit cold unless you are running 10.5:1 or more compression with a pretty big cam. I go at least a range hotter AFTER you get your carb situation straightened up. I'd also look for a plug that has a 5/8 hex rather than that 13/16 hex. The smaller hex is much nicer to use.

                        So you may want to see what a Champion RC14YC crosses to in an NGK and use that.

                        BTW, a platinum plug with an older ignition isn't always a good thing. They are harder to fire and if you are marginal on ignition that plug may be causing misfires because the ignition wasn't designed for that plug. You may not feel the missing, but it can happen.

                        A copper core plug is cheaper and much easier to fire. Yes, they require replacing at closer intervals, but you may be causing issues with a platinum plug you don't need.
                         
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