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GI: Crank Journal Brace for FE engine

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    GI: Crank Journal Brace for FE engine

    Hello. I got okayed by bpt323 to run a little interest gauging for a small batch product I'm working on.

    Mazda has made a two-piece journal brace for the FE DOHC engine. They aren't very common and somewhat difficult to come by (there's a single-piece sheet made brace too, and that's even more rare). I was interested in having one in full length, and accommodating the 94mm stroke for the DOHC stroker, so I started engineering a brace on my own. There has been cautious interest, and so here's the deal.


    Click for a larger image. All dimensions are for cost estimation only.

    The brace is intended to add toughness and stability by binding the journal caps together, sharing the load to neighbour bolts and preventing the caps from vibrating. It should make the engine more durable and quieter. It's not certain how great a difference it makes to a stock or close to stock engine, but you aim high on the engine build, you might want to give it a thought.

    Unfortunately it's not a simple bolt-on piece. Because I had to accommodate the 94mm stroke, fitting it to the sump is tricky. Aluminium sumps will need to have the oil fins trimmed down somewhat, and the steel sump must be cut and welded for extra space. Fortunately the windage tray won't interfere. Old bolts inevitably need to be replaced, I must consult ARP about this. I think they have suitable bolts/studs. Also if the engine is a Kia FE, the sump will need even more modifications as Kia has taller caps, and probably the oil pickup needs to be altered too. The replacement studs for Mazda engine won't work either.

    The brace will be made of ductile (nodular) cast iron. It's the same material the crank is made of, so it's very tough material, and the bonus to cast iron vs. milled aluminium alloy (which was considered) is better vibration dampening properties and neutral expansion rate vs. block and crank. The part will weigh about 2kg/4.5lb, so it's not terribly heavy if not featherweight either.

    I'm still inquiring machine shops for offers, so I can't tell the exact price yet. The unit price/cost should be between 100-150 USD; the minimum set I'm going to have to do is five pieces. Shipping costs for the item on Economy is roughly 40USD to Europe, North America and Russia, and 50USD elsewhere.

    #2
    Fortunately the windage tray won't interfere.
    which windage tray are you speaking of??? please post a pic

    Ryan
    ---Has ClubProtege helped you in someway? show your support by Contributing--- Click Here---

    1992- project FE3..... 313 WHP @ 9.3psi




    I pet my dash when I get into the car..."good car"
    he actually has a mazda tree, parts grow on it

    Comment


      #3
      my concerns would be.
      this looks like it would add a small gap between the block, and oil pan.
      will you extend the oil pump siphon or take to loss?
      how much clearance would you loose between the oil pan, and the ground?
      Next!
      sigpic

      Comment


        #4
        it looks like it fits inside the oil pan

        Comment


          #5
          FE3 engine!!!
          ---Has ClubProtege helped you in someway? show your support by Contributing--- Click Here---

          1992- project FE3..... 313 WHP @ 9.3psi




          I pet my dash when I get into the car..."good car"
          he actually has a mazda tree, parts grow on it

          Comment


            #6
            Originally posted by bpt323 View Post
            FE3 engine!!!

            I was wondering when someone would catch on about that!
            2011 BMW 128i 6 Speed Manual -- dd
            1990 Protege 4WD 5 Speed

            Comment


              #7
              Originally posted by 5l1mm View Post
              my concerns would be.
              this looks like it would add a small gap between the block, and oil pan.
              will you extend the oil pump siphon or take to loss?
              how much clearance would you loose between the oil pan, and the ground?
              If you have a B-series engine, this won't unfortunately fit, it's for F-engines only.

              However, the sump clearance is a valid issue. There can't be a sump spacer, because of the clearance to the right side subframe, and also because few of the transmission bolts are in the sump, creating a misalignment. Therefore it ,ust fit within the sump space. In steel sump this means unfortunately some reshaping and welding.

              Comment


                #8
                FE-DOHC!

                technically. lol
                ~PaTricK~


                -Current car's-
                ~ 92 Probe GT Turbo, 90 FE3 Turbo 626GT hatch, 97 KL mtx 626, 05 Mazda6, 09 Kia Sportage V6~
                What are you driving?

                Comment


                  #9
                  Originally posted by bpt323 View Post
                  which windage tray are you speaking of??? please post a pic

                  Ryan
                  It might be similar to the F2/F2T windage tray, though the Mazda FSM calls it a stiffener plate.

                  I can take a photo of an F2 one....

                  I was just going to use one of these in my engine.....its a whole lot less substantial tho that this cast one being proposed, its only made out of 2mm thick plate, with some extra bits welded in

                  Comment


                    #10
                    if i could get my hands on the part number for this one...
                    Attached Files
                    ---Has ClubProtege helped you in someway? show your support by Contributing--- Click Here---

                    1992- project FE3..... 313 WHP @ 9.3psi




                    I pet my dash when I get into the car..."good car"
                    he actually has a mazda tree, parts grow on it

                    Comment


                      #11
                      I think I have a part number for the stiffening plate, I just can't get to it right now! hopefully tomorrow.

                      Anyway, the brace issue has moved a notch forward; there's been stuff in the way, all the way. Here's a quick look of it as a wooden mock-up.



                      So far it does fit the block, but until I get the crank back it's pretty useless... also the clearances to the sump need to be checked. Dipstick clears the brace well, which was one of the things that worried me a bit. It looks promising again.

                      Comment


                        #12
                        get the wood piece perfect & put it into solid works/get all of the dimensions for it. i can have it mass produced then.

                        get that part number for me please.

                        Ryan
                        ---Has ClubProtege helped you in someway? show your support by Contributing--- Click Here---

                        1992- project FE3..... 313 WHP @ 9.3psi




                        I pet my dash when I get into the car..."good car"
                        he actually has a mazda tree, parts grow on it

                        Comment


                          #13
                          nice to hear! Def keeping an eye on this thread
                          ~PaTricK~


                          -Current car's-
                          ~ 92 Probe GT Turbo, 90 FE3 Turbo 626GT hatch, 97 KL mtx 626, 05 Mazda6, 09 Kia Sportage V6~
                          What are you driving?

                          Comment


                            #14
                            Got the part number for the FE stiffening plate, finally! It's FE1H-10-40YB but you'll need to modify the bearing caps to suit the plate (they have threaded holes.)

                            A link you might find useful: Mazda electric parts catalog unfortunately in Russian, but the text is self-explanatory.

                            Checked the brace with the 86mm crank. The mock-up fits with roughly 10mm to spare, so I'm hoping 5-6mm clearance with the 94mm stroke. The clearance to the sump was as I feared, there's 8mm interference and no room to reduce the height of the brace, so the sump gets the grinder. Don't know about the steel sump; ironically, the only F2 engine I have is the rare version with an alloy sump (AWD). Fortunately the brace clears the windage tray of the alu sump entirely, so that won't cause grief.

                            Comment


                              #15
                              Alrighty, the design starts to finalize, this is the shape I'm happy with. The wooden mockup didn't represent the shape but actually the space I can work with. The actual shape is this:




                              The weight is 1.61kg (3.55lbs), which shouldn't be too much. The new shape is a bit too complicated for building a prop just for the fun of it. A mold for cast iron needs to be 4% oversize to accommodate for contraction when the iron cools down. Machining requires only two jigs, so it shouldn't be too expensive either.

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