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  • custom header flanges

    if you're anything like me, you're sick of grossly substandard parts, in this case, I'm working header flanges for the GM 60V6, specifically the LX9 3500.

    in my case, I have 2 different flanges, one from British Car Conversions,

    https://www.britishcarconversions.co...header-flanges

    and one from Stainless Headers

    https://www.stainlessheaders.com/pro..._header_flange

    here are the flanges on a head...

    BCC





    stainless headers





    The BCC flange absolutely dwarfs the port, it's huge. and the stainless headers flange overlaps the port in some spots... pure garbage, putting it nicely. some of the mismatch on the BCC flange could get taken up by forming the primary tube to the inside of the flange, but it can be seen that it isn't the correct shape either.

    The grossly misshapen stainless headers flange isn't good for anything more than a paperweight IMO. you could form the tube to the flange, but then you end up with even more overlap into the port, which would KILL flow.

    so, everything is garbage, what do we do? we make our own! how? some simple measuring tools, some time, a spare head, and a cad program.



    to start things off, I cleaned the machined surfaces of the head, they need to be free of dirt and surface irregularities that could cause any measurements taken to be off.

    next, on the machined surface the flange will mate too, color in the whole thing with a sharpie, or machinist's blue if you feel like making a huge mess...







    using a scribe, make a reference line to work off of. most carpenter's squares have a small scribe in the end, or you can use a sharp piece of tungsten.





    when making your reference line, try and choose a machined point, in my case, I used the top of the bolthole for the lower bolt of the flange





    once you have set the reference point, make a nice long scribe line to measure off of. quick tip, if you scribe your line wrong, you can color it back in with the sharpie, and re-scribe, you really don't want to run the scribe hard into the metal if you ever intend on using the head again, in my case, the head I am taking measurements on dropped a valve seat, so it really doesn't matter too much.



    Next step is to measure off of your horizontal reference, and make several horizontal lines at even intervals, the more accurately you can do this, the easier your measurements will be, in my case, I made the lines about 2mm apart.



    next is to do the same thing on a vertical axis. in this case though, you don't want to use that as your basis for measurement, as it will be over the opening of the port, I measured and scribed a line about 30mm from that point, so that the entire reference point will be on metal.







    now, I know the axis for my measurements are tangent to the bolthole, so I can measure the diameter of the hole, as well as the distance to the other hole and put the holes in the drawing,









    next is the tedious part, we measure the port, from the reference lines, at each point, and plot it in our drawing. the more accurate data points you have, the more exact the flange will be.



    once that's done, you can clean up the drawing leaving you with something resembling a port, connect all of the points to close in the shape.



    proper port shape and position is important, if the flange overlaps the port, it will be a significant restriction to flow, if the flange is grossly oversized to the port, you'll lose velocity coming out of the port. I oversized my ports by about 10%, this ensures that any variances in the casting won't result in the flange overlapping the port, without being grossly oversize like the BCC flanges. I did this by using the offset tool in OnShape, and offsetting the port by 1.5mm, which creates a new set of points 1.5mm out from their original position, resulting in a port about 3mm wider and taller.



    if you're lucky, all of your ports are identical, and you don't need to remeasure each one, just copy and paste, if you're slightly less lucky. one or more of the other ports are a mirror image of the existing port, and you have to flip them, if you're really unlucky, rinse and repeat for the other ports. either way, the next step is to do the other ports, in my case, I measured the distance between each port, copied, pasted, and then copied, flipped, and pasted. then I traced out what I want the finished flange to look like.



    if you're better than me, all of your measurements will be spot on the first time, and you'll be ready to have it laser/water cut and start welding, but a smarter option is to have the flange 3d printed first, to verify fitment.


    Oops... I used dimensions for the bolt spacing from an older drawing and assumed I had measured them correctly...



    new measurements, new result! now I can easily see the small changes that need to be made, and make those corrections accordingly.



    now that you've verified everything is satisfactory, you can have the flanges cut from whatever material you see fit. in my case, I chose 304SS, to match the weld el's I'll be using for my manifold.

    something of note, because I am using weld el's with my flanges, they won't be fitted to the inside of the ports like you would normally see with headers. in this case, the port has the same perimeter as a 1.5" OD pipe or tube forming a pipe or tube to that shape may result in the pipe intruding into the gas flow, resulting in poor performance, so enlarging the flange further may be necessary to optimize performance. this technique will likely work in other applications, but will probably not be very effective for OHC engines, as the ports usually aren't in an as easy to measure position. I have hopefully one last revision to print, and I'll be ready to cut the flanges in something a little more permanent.
    Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

    I get bummed out every time I type "titties" in the search bar and nothing pops up....

    Built not bought, because bolt-ons don't...

  • #2
    Overlap doesn't matter in some spots on the flowbench. Would need to test it on an engine and see if it does anything. There is so much D shape to the port/runner already that I also don't know that there is an advantage with keeping it a D shape. More of a pain in the ass to deal with than using round tubing and flange ports. Since you are using round tubing, why make them D shaped?
    Ben
    60DegreeV6.com
    WOT-Tech.com

    Comment


    • #3
      I plan to form the tubes to the shape of the flange, they will be welded to the surface of the flange though. the end result should be a reasonably smooth transition from D to round. the abrupt transitions result in energy losses, I'm trying to keep as much energy in the exhaust as I can, to help spool the turbo faster.
      Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

      I get bummed out every time I type "titties" in the search bar and nothing pops up....

      Built not bought, because bolt-ons don't...

      Comment


      • #4
        Oh, the beauty of 3D printers - a relatively cheap and fast way to check if a design is going to work or not.
        -Brad-
        89 Mustang : Future 60V6 Power
        sigpic
        Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

        Comment


        • #5
          Originally posted by bszopi View Post
          Oh, the beauty of 3D printers - a relatively cheap and fast way to check if a design is going to work or not.
          no kidding! I can't wait for mine to get here, I'm going to be making all the cool stuff!
          Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

          I get bummed out every time I type "titties" in the search bar and nothing pops up....

          Built not bought, because bolt-ons don't...

          Comment


          • #6
            a quick update, Results are finally in! Top is my flange, upper middle is the BCC flange, lower middle is the "stainless headers" (SH) flange, and the bottom is all three stacked on top of each other.

            Some things to note, the strap holding the port flanges together can cause interference with the spark plugs the SH flange has really poor spark plug clearance, the BCC flange is much better, and my flange offers the most clearance, but admittidly, the difference in clearance between mine and the BCC isn't enough to make a significant difference.



            Here's some close ups of the ports. if you want an off the shelf flange, the BCC is by far the way to go, the SH flange if junk IMO. I have a few simple changes to make to my flange, that aren't anything really even visible here, the tolerance of the laser, and the tolerance in my drawing results in the bolts being a little bit too tight. I also want to change some of the contours ever so slightly. I'll also draw it for 1.5" OD tube, 1.625" OD tube, and 1.75" OD tube, as well as a die for forming the tubes. once I have them drawn, I'll post a link for downloads.

            Here are examples of each port's shape compared to the port shape. you can see the SH port is all over the place, even overlapping at points, total garbage. the BCC flange is way better, but only available in mild steel...

            1st port:







            2nd Port







            3rd port







            big picture:

            Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

            I get bummed out every time I type "titties" in the search bar and nothing pops up....

            Built not bought, because bolt-ons don't...

            Comment


            • #7
              Originally posted by ericjon262 View Post
              Yeah, those things are garbage. WTF? With modern manufacturing technology it's only laziness that keeps good products off the market.

              I guess the left edge of this port is what you're looking at tuning up on your design. It's interesting that we can see the granularity of the short laser cuts on the closeups of yours.
              Current:
              \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
              \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
              \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

              Gone, mostly forgotten:
              \'90 Pontiac 6000 SE AWD: slow but invisible

              Comment


              • #8
                Originally posted by Will'sFiero View Post

                Yeah, those things are garbage. WTF? With modern manufacturing technology it's only laziness that keeps good products off the market.

                I guess the left edge of this port is what you're looking at tuning up on your design. It's interesting that we can see the granularity of the short laser cuts on the closeups of yours.

                among other things, yes. I tuned the drawing a bit, and here is the "final" release, please read and understand the notes in the drawing. if you want to produce these commercially, please contact me first. When I get around to it, I'll draw up other port dimensions, these are for 1.5" primaries, or face welding pipes to the flange. there are 3 files, one DXF, one DWG, and one PDF. they are all the same drawing, if you need another file type, LMK and I'll see if I can make it happen.

                https://drive.google.com/drive/folde...6r?usp=sharing
                Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

                I get bummed out every time I type "titties" in the search bar and nothing pops up....

                Built not bought, because bolt-ons don't...

                Comment

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