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  • new carb heat box

    Today Bob received the latest carb heat box from the kit factory. He is 100% happy with it. However, it is not too smart to just make these without someone actually trying it on an engine AND seeing how the carb heat box fits the cowling. Bob THINKS it will be fine. But we need someone to try it on. Someone who already has their cowling made. Maybe even someone who is flying.

    If you are interested in trying this and can do the trial fit soon - please give me a call to discuss. Mark 512/626-7886

  • #2
    Here are some pics of it. I really need someone to trial fit this before we make a bunch of them. We need to make sure it fits within the carb heat box "cover" aluminum part we have been sending with the kits. image000000004 (1).jpgimage000000002.jpgimage000000003.jpg

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    • #3
      An update on the new carb heat boxes for those of you waiting. We now are confident that it is working well itself and also fitting well inside the sheet aluminum "surround" we have been sending with the 4 place, Companion, and Model 5 kits. Also we have sent that aluminum part on the most recent Patrols.

      We have made the decision to make two versions of the carb heat box. One version for the 6 cylinder engines like the pics shown above. And a slightly different version with a smaller filter for the 4 cylinder engine installations that do not need the big filter. The factory is starting to make them now - the ones for 540's. I will send down to the factory the smaller filter to make sure the ones they make for the 360's has the filter fitting well also. So good progress and hopefully have them available in a few weeks. Thanks for your patience to those of you waiting. Mark

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      • #4
        I have a “smaller” O-360, but angle valve 200hp, do I still get the smaller one?
        N678C
        https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
        Revo Sunglasses Ambassador
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        • Mark Goldberg
          Mark Goldberg commented
          Editing a comment
          Yes. All four cylinder engines can use the carb heat box with the smaller filter. But you could use the one with the bigger filter as well. No real need though. The air flow requirements for the 360 installations is more than adequate with the smaller filter.

      • #5
        Bottom LIne: Does this Box fit a Bendix FI Fuel Servo?

        I just read the Beartracks article on this Carb Heat Box. It seems like a great solution for both Bendix FI and a Carb. It will fit my Vetterman Cross Over Exhaust too. I have Bendix FI. So I wonder if the mount for the box to the Bendix Fuel Servo has the same footprint as a MS Carb? Does anyone know?
        Brooks Cone
        Southeast Michigan
        Patrol #303, Kit build

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        • #6
          Brooks, I can't answer your question. But things did change somewhat since my update on 3/24. I was told by a tech rep at K & N that they did have a smaller filter the same width of the larger one we made the box for. When Bob received it he saw that it was not the same width and was not compatible with the carb heat box we made. So there will just be one size fits all.

          There are a couple of carb heat that didn't work but would serve the purpose of checking for clearance etc as the dimensions are good. We could send these around so a builder could check fit. Mark

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          • #7
            Hi Mark, do I understand correctly, the latest plan is to use the same heat box with the big filter also for the Patrol?

            Do we already have photos of one fitted to an airplane?
            Curious how it looks.

            -Stefan
            Bearhawk "XHawk" Patrol, O-360, Trailblazer 80", tubeless 26" Goodyears, Stewart Systems. See XHawk Build Log.

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            • #8
              Yes Stefan - just one size carb heat box & one size filter. The bottom of the carb heat box (where it sticks out below the cowling) is covered nicely by the bent up aluminum piece we have always sent out the with 4 place & now Companion. In the last couple years we have sent that out with Patrols as well. Not sure if you got one. I do have some coming from the factory soon.

              There is another piece of aluminum required to go from the nose bowl to the top of the filter. I have not seen the finished look of the new carb heat box with both those pieces of aluminum fitted.

              However, 8 or 9 of the carb heat boxes just got sent out to builders. Hopefully we will see some pics soon. Mark

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              • #9
                What is the latest on the heat boxes?
                Anybody has already installed them on a Patrol?
                Super curious to see a picture.
                Bearhawk "XHawk" Patrol, O-360, Trailblazer 80", tubeless 26" Goodyears, Stewart Systems. See XHawk Build Log.

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                • #10
                  I have one. I have fit it up, but not installed it yet. It fits with a Vetterman Cross Over Exhaust without modification but its close. Bob said he thought it would be fine even without a heat shield using Bendix Fuel Injection.
                  image.jpg

                  if you read Kent Paisley’s Speed with Economy, want to get creative, and look a bit foolish it fits backwards too. so unfiltered ram air could be fed straight into the box maybe getting a bit more power improve volumetric efficiency up high. I’ve wondered….if the engine consumed filtered air from the lower plenum (instead of fresh air from the open atmosphere) would certainly lower the amount of air exiting the lower plenum, might it improve cylinder head cooling a bit too at the cost of some power?

                  But no one does it so I assume there more to it then my creative mechanical thoughts might be able to understand.
                  Attached Files
                  Last edited by Bcone1381; 11-21-2023, 01:01 PM. Reason: Clarify, add photo, added weird offshoot idea
                  Brooks Cone
                  Southeast Michigan
                  Patrol #303, Kit build

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                  • gregc
                    gregc commented
                    Editing a comment
                    Since it is so close when using a Vetterman exhaust, I tried to get K&N to provide some info on the temperature rating for the flexible/rubber stuff used in their filters. I was hoping for a "good to x degrees". All I got was the lawyerly answer that it is "adequate for the intended application".

                  • Bcone1381
                    Bcone1381 commented
                    Editing a comment
                    (If I recall my conversation correctly) Bob's view was that as long as it did not touch the exhaust I am fine because AL is so good at dissipating heat.

                • #11
                  Thanks for the pic. I like that it is lower profile than the MA4. What I don't quite understand is how the top part cuts into the cowl, sort of undercutting the nose bowl. Doesn't that create a strange scoop? I guess the filter is big enough for an O-360 that the top part could be ignored (not exposed to the airstream)??


                  image.png
                  Bearhawk "XHawk" Patrol, O-360, Trailblazer 80", tubeless 26" Goodyears, Stewart Systems. See XHawk Build Log.

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                  • #12
                    Hi Stefan. The top takes a piece of aluminum. It is kind of recessed at the top but doesn't look bad or create any problem. Mark

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