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M20B30 Stroker build in progress

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    #16
    @packratbimmer - the block is from IX, but its a regular rwd car.
    I know what you mentioned, and I have already replaced the intermediate shaft and installed a M21 pump (better flow).
    Also stock IX engine needs to be ran with E34 Oil pan, however I had the original dipstick location drilled at a machine shop, when the block was bare.
    Now the only difference is that I am using an adapter to install the oil relieve valve.

    @digger - I will be running MS1 Extra (this is what I have lying around). Tune is not an issue, as I have a very good tuner that is a friend. The care will be tuned on the dyno, once I do the break in.


    P.S. Turned out that I had the wrong piston rings (the retailer send me M50 not M54 ones) so I havent installed the pistons yet.
    Luckily a good friend of mine has a set so I will get those tomorrow and start working on the engine. If I am lucky I might be able to start the engine by the end of next week. (waiting for some small parts from the BMW Dealer)

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      #17
      Originally posted by bmwmaster81 View Post
      So without a squish the engine is more proned to knock ? Or nock can't be registered so fast ?
      Is it because of less turbolence ?

      I also have same parts here crank and pistons for a future build but the resulting high CR was the problem which i was conserned of.
      Althoug i have a standalone ecu im not sure if the engine would be to much knock limited. I think it would be an nice engine for E85.
      yes, without squish the engine can be more prone to knock when running higher compression (i know a few people personally in this part of the world with builds with this issue and there arent many around here with m20 builds). you can alter the ignition timing but this hurts performance if you need to retard it excessively. Its actually a pretty important aspect of a high performance engine often overlooked in the m20 world, many aftermarket pistons dont have the dome shape to achieve it on the 885 head. There are a few sources for pistons around these days that have these features. there are still good performing builds without this but its giving up free performance IMO

      When you have have squish action occurring as a result of the correct clearance the piston squeezes the air against the head which forces the air out at at high velocity towards the middle of the chamber increasing mixing and turbulence improving the combustion efficiency. This reduces the knock tendency but improves power output. There seems to be empirical evidence that it improves bottom end torque on the m20 which makes sense as at low rpm there isnt enough velocity to help with combustion turbulence so squeezing the air helps.
      Last edited by digger; 01-08-2016, 03:38 PM.
      89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

      new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

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        #18
        Zoomer - Thanks for the information! I am psyched about using my 325iX engines in my RWD cars. I have been looking for the "formula for a while now. Any chance you could take a pick of the relief valve adapter? Thanks

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          #19
          1,25mm piston to head clearance? Sounds waay big but what do I know..
          Originally posted by bmwmaster81 View Post
          So without a squish the engine is more proned to knock ? Or nock can't be registered so fast ?
          Is it because of less turbolence ?

          I also have same parts here crank and pistons for a future build but the resulting high CR was the problem which i was conserned of.
          Althoug i have a standalone ecu im not sure if the engine would be to much knock limited. I think it would be an nice engine for E85.
          The right static compression ratio depends on a number of things. Most importantly octane rating, possible boost pressure AND YOUR CAM.

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            #20
            @digger - do you think that making the combustion chamber hemispherical will improve this?

            @packratbimmer - I will take a pic tomorrow morning and post it.

            Now some progress from today.

            Bottom end is mostly assembled. Today I installed the pistons, also wanted to be sure for the lift and the piston shape, so I did a test with some clay inside the combustion chamber - there is at least 2.4mm between the piston and the intake valve at any time:


            All the rotating assembly seems fine, but just when I was about to install the head, I checked it and it turned out that I did an epic fail - I assembled the wrong head (I am keeping this head for my turbo build), so I had to call it a day. I will assemble the proper head and install it tomorrow. And I will be just waiting form some minor stuff from the bmw dealership (gaskets mostly) to finish the engine.

            Some pics of the pistons inside the block:




            The piston at TDC

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              #21
              Wow 2.4mm valve clearance is really good :-) maybe it wasn't necesery to skim the pistons down ?
              I think about 1.2 mm would be enough ?

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                #22
                Catcams claim that minimum distance is 1mm and recommended is 1.5mm,

                However I wanted to be safe, so 2.4 sounds good to me.

                Today I installed the head and torqued the head bolts (metric blues equivalent).
                Now all that is left are some gaskets and I will have everything necessary to assemble the engine.
                Since I had nothing to do in the garage, I did a mockup wit the Hartge headers I am going to run :)

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                  #23
                  Some more progress:

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                    #24
                    How much was shaved from the edges of the piston?

                    1986 327i
                    transaction feedback
                    DIY thing
                    meh

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                      #25
                      Sub'd always been interested in doing a 3.0 stroker
                      My Garage
                      2001 Z3 2.5i Steel Gray/Black (Lexi)
                      1988 325ix Diamond Schwartz/Black (Izzy)
                      1989 325i Cirrus Blue/Houndstooth (Stitch)
                      Feedback

                      Instagram: Stone.Hopkins

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                        #26
                        Originally posted by modernist View Post
                        How much was shaved from the edges of the piston?
                        1mm from the top and 1.75mm from the edges.

                        Here is some progress from yesterday:





                        The engine is mostly assembled, today I will start working on the engine bay (its very very dirty)

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                          #27
                          Looking good!
                          AWD > RWD

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                            #28
                            Can't wait to see this run! Wow.

                            1986 327i
                            transaction feedback
                            DIY thing
                            meh

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                              #29
                              Originally posted by modernist View Post
                              Can't wait to see this run! Wow.
                              believe me I am even more excited.
                              If I have time I will drop the engine in the car this week.

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                                #30
                                Some progress from today (and the past few days)

                                Someone asked me about the IX to regular oil pressure relieve valve adapter -
                                here it is:




                                The oil pan after a couple of hours of scrubing:




                                Here is my home made M50 to M20 TPS adapter :) (I used an old M20 TPS and cut it a bit)





                                Unfortunately still pointing in the wrong direction




                                And finally today I decided I am ready to drop the engine.




                                Final progress for the day (still quite a few things left to do but I am quite happy with the progress)




                                So tomorrow will be the big day when I should be able to do the first start.

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