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Needlessly complex 2.8L

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  • Needlessly complex 2.8L

    Building up a 2.8L out of my 1986 Fiero GT. Under the advice of a very trusted friend (BetterThanYou, as he's known here) I picked up Aluminum 3.4L heads. Of course, this also necessitates a few other modifications.

    Exhaust: Headers need to be made in order to match the new locations of the exhaust ports. Planning on making equal length shorty headers, which will then have to work through a new exhaust system.

    Intake: The stock 3.4L lower intake plenum was grabbed, but I left the upper, as I have some inexplicable desire to keep the engine looking and sounding as close to stock as is humanly possible. So, I'm trying to find a way to get the stock Fiero upper intake to somehow match the bottom (Fiero has a single followed by a pair of ports, or "siamesed". 3.4L are all equally spaced). Thinking of getting an upper intake made somehow.

    Ignition: Distributor had to be removed as the new heads are in the way, and instead, a DIS system is taking it's place. An in-pulley crank trigger will be used.

    Internals: Here's where the money becomes a problem... Under normal conditions, compression ratio would be 13:1. As such, custom pistons need to be made, which is quire an expensive venture for a student. When I do get them made, I plan to get them as light as I can (Strength isn't as big a concern to me, as I wont be running Forced Induction or Nitrous Oxide) and run a gapless/moly combination for ring.

    Other details: Seeing as how the engine is out of the car, was hoping to work with BetterThanYou into making a dry sump system, as well as figuring out some sort of way to run the Fiero's valve covers. No intentions of touching displacement, cam or aspiration set up, and yes, I realize that sounds very counter-productive.
    "There's no 'I' in team, Grif."
    "There's no 'u' either. So if I'm not on the team,
    and you're not on the team,
    NO ONE'S ON THE GOD DAMN TEAM!"

  • #2
    Pistons, easy, no custom needed. Ones from a 2.8 FWD aluminum headed motor (gen2 motor) would be what you need. Such as the early Beretta's etc.

    Run the #'s through the compression calc again, 13.1 seems a bit high with that bore size. But yes it will be up there with the stock iron head slugs.
    sigpic New 2010 project (click image)
    1994 3100 BERETTA. 200,000+ miles
    16.0 1/4 mile when stock. Now ???
    Original L82 Longblock
    with LA1, LX9, LX5 parts
    Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

    Comment


    • #3
      Originally posted by IsaacHayes View Post
      Pistons, easy, no custom needed. Ones from a 2.8 FWD aluminum headed motor (gen2 motor) would be what you need. Such as the early Beretta's etc.

      Run the #'s through the compression calc again, 13.1 seems a bit high with that bore size. But yes it will be up there with the stock iron head slugs.
      I had BetterThanYou run the numbers with me. It's 13:1 for the iron heads, and I don't know about the aluminum 2.8s, but the 3.4 ones take it down to 8.5 which is too low.
      "There's no 'I' in team, Grif."
      "There's no 'u' either. So if I'm not on the team,
      and you're not on the team,
      NO ONE'S ON THE GOD DAMN TEAM!"

      Comment


      • #4
        I've thought about a swap too....but in CA, it's really tough!!
        I may just go ahead and drop in the 3.4 GMPP HT crate engine, since it's an easy swap and requires only a weekend!!. There is no visible difference from the exterior, but the difference in power is great, or so I've heard & read!! Late.
        I need a bigger engine!

        Comment


        • #5
          Yes, but I don't want to change the displacement. I'm a bit of an eccentric, I'm afraid... lol
          "There's no 'I' in team, Grif."
          "There's no 'u' either. So if I'm not on the team,
          and you're not on the team,
          NO ONE'S ON THE GOD DAMN TEAM!"

          Comment


          • #6
            Lot's of people modify their engines, look at anyone with a 350 who has modded it for more torque. They increase the displacement for added power. Generally they go to a stroker kit which converts the displacement to 383 and bore over. Essentially when you overhaul your engine, you are doing just that, granted the engine requires machining. So increasing the displacement is paramount for some engine overhauls.

            But, I can see why you don't want to follow through. Late.
            I need a bigger engine!

            Comment


            • #7
              Yes. Well, I don't know, I just want it to sound as close as is humanly possible to stock, as well keep the displacement and aspiration original. Sentimentality, I suppose.
              "There's no 'I' in team, Grif."
              "There's no 'u' either. So if I'm not on the team,
              and you're not on the team,
              NO ONE'S ON THE GOD DAMN TEAM!"

              Comment


              • #8
                Unless you change the cam, it will sound stock...

                Punch in the #'s in the CR calc and see what 2.8 aluminum pistons comes out to... What compression are you wanting?
                sigpic New 2010 project (click image)
                1994 3100 BERETTA. 200,000+ miles
                16.0 1/4 mile when stock. Now ???
                Original L82 Longblock
                with LA1, LX9, LX5 parts
                Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.

                Comment


                • #9
                  About 10 to 1.

                  Any chance you happen to have the stats on those 2.8L pistons?
                  "There's no 'I' in team, Grif."
                  "There's no 'u' either. So if I'm not on the team,
                  and you're not on the team,
                  NO ONE'S ON THE GOD DAMN TEAM!"

                  Comment


                  • #10
                    They are in the CR Calc. Just select a 2.8 Alum head, stock bore, and default values, and all needed specs will be displayed once you hit calculate.
                    -Brad-
                    89 Mustang : Future 60V6 Power
                    sigpic
                    Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

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                    • #11
                      2.8 is high because they don't have a dish in the pistons.
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                      • #12
                        you could do what im planning on my 2.8/3400 build, which is to use 3100 pistons mated to 5.85" sbc rods, which yields like 8.7 cr with (IIRC) .043 quench. Why 8.7? Because ill be running a turbo, so this may not need apply to you since you are going n/a, in which you may want a little more compression
                        Originally posted by Mars
                        Haha ^ Wrong Wheel Drive.
                        S10 Blazer 4.3, turbo LX9 in its future...
                        No 60šV6 at the moment

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                        • #13
                          Yep yep. Thanks for the idea with different con rods though... Hadn't considered that.
                          "There's no 'I' in team, Grif."
                          "There's no 'u' either. So if I'm not on the team,
                          and you're not on the team,
                          NO ONE'S ON THE GOD DAMN TEAM!"

                          Comment


                          • #14
                            Well, the most I could get with the 2.8L aluminums was 9.27 with a .01" milling. Not sure how far it can be safely pushed in terms of milling the heads.
                            "There's no 'I' in team, Grif."
                            "There's no 'u' either. So if I'm not on the team,
                            and you're not on the team,
                            NO ONE'S ON THE GOD DAMN TEAM!"

                            Comment


                            • #15
                              Originally posted by Romeo View Post
                              Well, the most I could get with the 2.8L aluminums was 9.27 with a .01" milling. Not sure how far it can be safely pushed in terms of milling the heads.
                              The machine shop milled my 3400 heads .01 bc they werent perfectly flat, just use a thicker head gasket from bens store.
                              Originally posted by Mars
                              Haha ^ Wrong Wheel Drive.
                              S10 Blazer 4.3, turbo LX9 in its future...
                              No 60šV6 at the moment

                              Comment

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