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  • Carb parts and function

    Here are some questions for those of you who are carburetor experts. Here is the history. I started driving my truck with a WCFB which was always lean. Did not know how to make it run more rich. Purchased a AFB with manifold and aircleaner from E-bay and it ran great. But my mileage went from 19.96 MPG to less than 14. A friend let me use metering rods from another AFB that he had taken off a Farrai 308. My truck runs great with the different rods but is sluggish off the line. So we took the springs from under the 308 vacuum plunger and my truck is no longer slow off the line.
    I may have found a start for better mileage but also know that just going lean will not give good mileage.
    The metering rods from the WCFB measured .060 WOT and .072 at cruise.
    The OEM rods for my AFB measure .045 WOT and .069 at cruise.
    The rods from the 308 measure .060 WOT and .073 at cruise.
    After changing the springs from the 308 to my AFB and considering the size of the metering rods had I just increased the spring tension on the WCFB perhaps it would have run just as well as the AFB now does and perhaps my mileage will now come back with the AFB. I am looking for feed back from those of you who know carburetors.
    Also here are some part numbers, does anyone know the diameters of these metering rods. All are Stude part numbers as I cannot find Carter specs only Edelbrock specs.
    WCFB parts
    537402, 537403, 537404,537159
    AFB parts 1559370, 1559463, 1559464
    As always help from those who know is appreciated.
    Ted

  • #2
    quote:Originally posted by studepickups

    Here are some questions for those of you who are carburetor experts. Here is the history. I started driving my truck with a WCFB which was always lean. Did not know how to make it run more rich. Purchased a AFB with manifold and aircleaner from E-bay and it ran great. But my mileage went from 19.96 MPG to less than 14. A friend let me use metering rods from another AFB that he had taken off a Farrai 308. My truck runs great with the different rods but is sluggish off the line. So we took the springs from under the 308 vacuum plunger and my truck is no longer slow off the line.
    I may have found a start for better mileage but also know that just going lean will not give good mileage.
    The metering rods from the WCFB measured .060 WOT and .072 at cruise.
    The OEM rods for my AFB measure .045 WOT and .069 at cruise.
    The rods from the 308 measure .060 WOT and .073 at cruise.
    After changing the springs from the 308 to my AFB and considering the size of the metering rods had I just increased the spring tension on the WCFB perhaps it would have run just as well as the AFB now does and perhaps my mileage will now come back with the AFB. I am looking for feed back from those of you who know carburetors.
    Also here are some part numbers, does anyone know the diameters of these metering rods. All are Stude part numbers as I cannot find Carter specs only Edelbrock specs.
    WCFB parts
    537402, 537403, 537404,537159
    AFB parts 1559370, 1559463, 1559464
    As always help from those who know is appreciated.
    Ted
    Ferrari 308 with an AFB?

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    • #3
      Allan you need to know my friend. His speciality is exotic intake and exhaust manifolds. The Farrai was converted by him and the AFB was turbo charged. That same car is now sporting Corvete coils, fuel injection and is turbo charged with an even larger turbo. Ted

      Comment


      • #4
        quote:Originally posted by studepickups

        Allan you need to know my friend. His speciality is exotic intake and exhaust manifolds. The Farrai was converted by him and the AFB was turbo charged. That same car is now sporting Corvete coils, fuel injection and is turbo charged with an even larger turbo. Ted
        Early 308s had Webers, so I am assuming he built some sort of manifold to replace that early fuel injection on the slightly later models. It was troublesome to say the least.

        I would love to see a 308 with an custom AFB manifold and turbo! Do you have any pics?

        Comment


        • #5
          The rod sizes tell me you might have a fairly large primary jet. I run 75/47 with a 98 jet in 1406 Edelbrock. Open up the carb and pull a jet, the size is stamped on it but I always need a magnifying glass to read them.

          The Edelbrock website has a tuning chart with compatible rods and jets. It's a good place to start with your tuning.

          ErnieR


          On its way to a 15.097 Spring 2006.

          Comment


          • #6
            Thanks Ernie I have been looking at those kits. Just not sure which way to go yet as experimenting isn't through. The suggestions will help make those determinations. I am looking for the best mileage without the hesitation off the line. It has a truck transmission so first gear is low compared to the car T85. Allan, I have been looking for Scott's website and cannot remember it. I will call him tomorrow and get it to you. If I remember correctly he has many pictures of the car on the site. when one opens the hood not knowing the 308s you cannot tell it isn't a factory application. Ted

            Comment


            • #7
              What bothers me is that I didn't hear anything about reading the plugs, any changes to the idle mixture setting, float level, vacuum readings, timing, or acc pump shot.

              Comment


              • #8
                I would also recommend changing one component at a time and recording what came out/went into the carb, and seeing if the results are any better or any worse. That way you know what needs to be kept in the carb after the upgrade, or what needs to be returned to stock. Ordinarily, it's easier to step a size up or down and see if there's any noted changes in the carb behavior. If a person isn't careful, too many changes at one time may result in a carb that performs much worse than it did before it was modified.

                [img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/My%201950%202r5%20Studebaker%20Pickup%20with%20turbocharger/P1000137-1.jpg[/img=left][img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/My%201950%202r5%20Studebaker%20Pickup%20with%20turbocharger/P1000145-1.jpg[/img=left][IMG=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/Ex%20Studebaker%20Plant%20Locomotive/P1000578-1.jpg[/IMG=right]
                [IMG=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/My%201964%20Studebaker%20Commander%20R2/P1010168.jpg[/IMG=right]

                1964 Studebaker Commander R2 clone
                1963 Studebaker Daytona Hardtop with no engine or transmission
                1950 Studebaker 2R5 w/170 six cylinder and 3spd OD
                1955 Studebaker Commander Hardtop w/289 and 3spd OD and Megasquirt port fuel injection(among other things)

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                • #9
                  Everything else was checked before starting with the carb. Now as recomended we are looking at the carb one piece at a time. We know what size the metering rods and springs are that we have been working with, but are not familar with the sizes of the studebaker rod numbers. We have Edlebrocks info and part numbers and can use them. If Studebaker used rods with better numbers than Edlebrock has currently that may be the way to go.

                  Comment


                  • #10
                    AFB metering rods have the number stamped on the side(i.e. 16-241)Use chart http://cars.rasoenterprises.com/Carb...FB_Jetting.htm to determine size. Some later numbers
                    read actual size.(i.e. 16p-6846 is .068-.048) I acquired quite a few for use in playing with my 400 cfm which I haven't done as yet. #10-201 strip kit comes up on ebay from time to time which gives good selection of jets and rods. You need jet size and vacuum setting of spring as starting point and vary jet area with different rods. I would begin by progressively leaning cruise by increasing first step diameter till it's too lean and work from there. Hard to do without a good selection of jets and rods.

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                    • #11
                      Allan here is the website if you choose to see some of the photos of the conversion to coil on plug, injection and some of the manufacturing of the components of the 308. http://www.buildandtune.com/webuilt.html

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