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2.8L M20 9.8:1 stroker build: my 323i reincarnated

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    2.8L M20 9.8:1 stroker build: my 323i reincarnated

    So the story goes.. I crashed my beloved 323i in a sharper than I thought downhill turn that caused unexpected oversteer. It was 1000% my fault with my shit driving ability is the reason I mangled one of the last 323i's to exist in California.

    After dumping about $1k into straightening the body it became clear that the 323i wouldn't be completely straight without spending inordinate amounts of money.

    So I started searching for an early model shell. I saw an ad on craigslist for a pretty shitty looking 325e, but it was super close so I basically said fuck it.

    Owner was a skater dude who wanted to drift it but lost interest after he got an E36.

    He offered I take it for $200 so he'd have money to go to the beach with his friends...

    So hell yeah I bought it

    Edit: I found a crisp $20 bill while cleaning the carpet, so it really was an $180 car.

    --------------------------------------------

    Alright, so I'm gonna try and help people who want to do this build by listing the parts required to make it happen. I will update it as I think of stuff.

    Main Engine parts:
    -Any M20 block
    -885 (325i) head. At least a 272 cam.
    -84mm Crankshaft from a 2.8 M50/52engine. E36 328i, E39 528i, etc.
    -Stock 325i short skirt pistons. These pistons have the domed top and the flat skirts.
    -130mm rods. Either from 325e, 320i, 323i etc
    -325i intake manifold, throttle body, AFM, airbox, boot, and ICV

    Machining:
    -This spacer (Just ask a local machine shop)
    -My block was decked exactly 0.020" or .508 mm for a CR of exactly 9.81:1 assuming a stock M20B25 is exactly 8.8:1
    -Shave off the non-structural looking part of the piston skirt.
    -Turn the crankshaft counterweights down pretty much all the way, right before you start hitting the other side of the crankshaft (the part that sticks out next to the connecting rod bearings)
    -Get the entire assembly professionally balanced: pistons, rods, crankshaft, flywheel, vibration damper, fan pulley, and pressure plate

    Electrical: (starting from 325e)
    -325i complete engine wiring harness
    -325i injector harness
    -Toothed crank wheel
    -CPS and CPS bracket
    -Motronic 1.3 ECU (173)
    -Custom chip (ie Sssquid, or just go full standalone)
    -325i Spark plug wires (for CID sensor)
    -NGK BPR6ES spark plugs

    Fuel:
    -At least 19 lb injectors.
    -325i 3.0 bar Fuel pressure regulator
    -Stock pump should be fine.

    Cooling:
    -Stock cooling is fine. Either late or early model.
    Last edited by betz; 03-21-2018, 10:00 AM. Reason: Machining for build
    '86 Burgundrot 325 2.8 stroker.

    Build thread

    Other cars:
    2000 Porsche Boxster
    2006 Subaru Outback XT 5MT
    1972 Porsche 914

    #2


    '86 Burgundrot 325 2.8 stroker.

    Build thread

    Other cars:
    2000 Porsche Boxster
    2006 Subaru Outback XT 5MT
    1972 Porsche 914

    Comment


      #3
      Took you long enough to post pics! hahah

      Where is the rear trim? lemme have it
      Simon
      Current Cars:
      -1986 BMW 325e & 1968 Datsun Roadster 2000
      Previous Car Count : 21 ... and climbing...
      Originally posted by Melon
      Let it be known to all. Simon fucking keeps it real.

      Comment


        #4
        Car had a "blown head", didn't care since I already had a "e" block in the works for a 2.7 stroker for my 323i.



        '86 Burgundrot 325 2.8 stroker.

        Build thread

        Other cars:
        2000 Porsche Boxster
        2006 Subaru Outback XT 5MT
        1972 Porsche 914

        Comment


          #5
          Originally posted by 2mAn View Post
          Took you long enough to post pics! hahah

          Where is the rear trim? lemme have it
          Yeahhhh the photos were way too big. Undid it and compressed them. More incoming...

          And what trim? From the 323i?
          '86 Burgundrot 325 2.8 stroker.

          Build thread

          Other cars:
          2000 Porsche Boxster
          2006 Subaru Outback XT 5MT
          1972 Porsche 914

          Comment


            #6
            Originally posted by betz View Post
            Yeahhhh the photos were way too big. Undid it and compressed them. More incoming...

            And what trim? From the 323i?
            No, the diving board. Its missing in the pic. Trying to make some front delete panels since nobody else.

            BTW Im VERY curious about the 2.8L M20 build so I will be watching closely
            Simon
            Current Cars:
            -1986 BMW 325e & 1968 Datsun Roadster 2000
            Previous Car Count : 21 ... and climbing...
            Originally posted by Melon
            Let it be known to all. Simon fucking keeps it real.

            Comment


              #7
              I pulled the 731 head from the 323i, got the head inspected by a machinist but it needed new valve guides. I was planning on using valves from this 885 head I picked up, but he said he could't make them fit easily. So, I decided to go a different route...

              E36/E39 84mm M52 crank, 325i short skirt pistons, eta rods, 885 head. 2.8L, 9.75:1+ compression. My machinist decked the head and measured the squish band clearance, so it could easily be closer to 10:1. 5mm off the block is standard to bring it to normal clearance. Here's some general info on the 2.8 build: http://www.e30zone.net/e30zonewiki/i...Building_a_2.8
              Last edited by betz; 09-18-2017, 07:49 PM.
              '86 Burgundrot 325 2.8 stroker.

              Build thread

              Other cars:
              2000 Porsche Boxster
              2006 Subaru Outback XT 5MT
              1972 Porsche 914

              Comment


                #8
                Got the block hot tanked, then shot peened..



                '86 Burgundrot 325 2.8 stroker.

                Build thread

                Other cars:
                2000 Porsche Boxster
                2006 Subaru Outback XT 5MT
                1972 Porsche 914

                Comment


                  #9
                  please keep posting more progress
                  Simon
                  Current Cars:
                  -1986 BMW 325e & 1968 Datsun Roadster 2000
                  Previous Car Count : 21 ... and climbing...
                  Originally posted by Melon
                  Let it be known to all. Simon fucking keeps it real.

                  Comment


                    #10
                    Crankshaft turned, rods and pistons glass beaded, piston skirts shaved. Also got my company to machine me a spacer for the front crankshaft oil seal.





                    '86 Burgundrot 325 2.8 stroker.

                    Build thread

                    Other cars:
                    2000 Porsche Boxster
                    2006 Subaru Outback XT 5MT
                    1972 Porsche 914

                    Comment


                      #11
                      The pistons were knurled and the whole assembly was balanced...



                      '86 Burgundrot 325 2.8 stroker.

                      Build thread

                      Other cars:
                      2000 Porsche Boxster
                      2006 Subaru Outback XT 5MT
                      1972 Porsche 914

                      Comment


                        #12
                        Block painted aluminum color, high temp engine block paint.



                        '86 Burgundrot 325 2.8 stroker.

                        Build thread

                        Other cars:
                        2000 Porsche Boxster
                        2006 Subaru Outback XT 5MT
                        1972 Porsche 914

                        Comment


                          #13
                          Meanwhile, pulled the engine out the 325e and put the Z3 steering rack and ground controls from my 323i in.





                          '86 Burgundrot 325 2.8 stroker.

                          Build thread

                          Other cars:
                          2000 Porsche Boxster
                          2006 Subaru Outback XT 5MT
                          1972 Porsche 914

                          Comment


                            #14
                            Burgundrot is a good start.

                            Sad to lose a 323...was it euro bumpered?

                            What does the knurling do on the skirts?

                            Comment


                              #15
                              Originally posted by LateFan View Post
                              Burgundrot is a good start.

                              Sad to lose a 323...was it euro bumpered?

                              What does the knurling do on the skirts?
                              It twas. Forgot to mention, the front got a little mangled, but I've already swapped the rear onto the "e". I'm looking into straightening the front but there's hardly any chrome bumper shops around anymore.

                              Knurling helps hold oil at the edge of the skirt. Its also allows a worn piston skirt to perform more like a new one because knurling raises the edges of the skirts up, so that it fits tighter.

                              It also looks cool.
                              '86 Burgundrot 325 2.8 stroker.

                              Build thread

                              Other cars:
                              2000 Porsche Boxster
                              2006 Subaru Outback XT 5MT
                              1972 Porsche 914

                              Comment

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