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    e30 Engine Type

    Hi All,

    So, I'm a relative newbie to the world of e30s and hope I don't get slammed for asking this question. I've tried to research online myself and even called BMW without success.

    I bought a 1990 325i Sedan about 18 months ago. Based on VIN and realoem this car is supposed to have the m20 2.5l engine. I'm trying to confirm this is the motor I actually have in my car. The reason I'm wondering is that the head only has 2.7eta on the casting.

    So, a couple questions:
    What is best way to identify the actual engine? The numbers above the oil pan on the driver side by the alternator are 22166216 but I haven't been able to find a source to interpret these numbers into the engine type and BMW service wasn't helpful.

    Is it even possible to put a 2.7eta head on a 2.5l engine? If yes, and I have the 2.5l engine, it seems like I would get a nice performance boost by going to an 885 head based on other posts I've read. Is this conclusion valid?

    The car seems way too quick to only have 128 HP so I'm guessing I have the 2.5l, but since I've never driven an e30 I don't have a comparison for my butt-dyno.

    Thanks in advance for any help!
    Own:
    2009 335i Sedan - Silver with Black Interior
    1990 325i Sedan - Black with Tan Interior

    Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

    #2
    If it's an i car, I don't see why it would have a 2.7 swapped in.

    If you have a 2.5i, it already has the 885 head. (The "Super ETA" from '88 also has the 885 head I believe)

    The 2.7 head isn't near as good as the i head. It doesn't flow as well, it has fewer cam bearings, and weak valve springs.

    <EDIT>...
    Last edited by LateFan; 05-02-2017, 11:24 AM.

    Comment


      #3
      Thanks for the reply.

      I know I have the 2.7eta head because of the casting on the actual head and that is why I'm concerned they actually swapped to the 2.7l engine. I'm thinking someone may have wanted to build a 2,7l stroker so did the swap but just hadn't put on the 885 head yet due to all the other components that need to change to complete the build.

      The person I bought the car from 18 months ago was really into e30's but I'm not able to get in touch with him any more to ask if he had done a swap.
      Own:
      2009 335i Sedan - Silver with Black Interior
      1990 325i Sedan - Black with Tan Interior

      Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

      Comment


        #4
        Ohh..

        Not a 731 head, or a 200 head...?



        Could be a replacement with a super eta after a failure?? Stroker modification??

        2.5 block exhaust side... (these are from the M20 forum sticky)
        Click image for larger version

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        2.7 block exhaust side..
        Click image for larger version

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        Comment


          #5
          Ok, so thanks to LateFan for the awesome engine references!

          I've concluded I have a m20b25 block with a 2.7eta head. Go figure!

          Here's my logic (see photos). The block has lines going to the oil cooler which from my understanding was ONLY available on the m20b25. The head is clearly an 2.7eta head.

          The first question I have is if it is possible to fit the oil cooler to the m20b27 engine?

          The next question I have is how much performance gain would I get from changing the head to the 885?

          Thanks to all for a great forum!
          Attached Files
          Own:
          2009 335i Sedan - Silver with Black Interior
          1990 325i Sedan - Black with Tan Interior

          Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

          Comment


            #6
            pretty sure the "regular" ETA head wont fit onto a m20b25 bottom end without mods. the raised dome of the piston would hit the head.

            there should be casting number on the head, like xxxx 885, xxxx 731 or xxxx200 its on the intake side above the numner 3 & 4 ports midway along length so might be hard to see

            some blocks have stamped code on the inlet side something like 25 6k-1 or 27 6L or something designating 2.5 or 2.7L
            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

            Comment


              #7
              Hey Digger,

              I tried to find numbers to id the engine block and it is still in the car so I didn't find anything. The engine is pretty dirty which is why I tried to use other ways to id the engine block.

              Did you see the photos of the head that shows it is the 2.7eta in the casting?

              Any thoughts on the oil cooler feature of the engine as shown in the photo and using that to identify as m20b25 instead of m20b27?

              Thanks!
              Own:
              2009 335i Sedan - Silver with Black Interior
              1990 325i Sedan - Black with Tan Interior

              Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

              Comment


                #8
                if it is a real eta head then id suspect an eta block or atleast eta pistons . might be able to check in spark plug holes with one of those little cameras/borecopes to see the piston and combustion chamber

                you can retrofit the m20b25 oil cooler filter housing onto the eta block so this isnt enough evidence.

                what does the intake manifold look like?
                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

                Comment


                  #9
                  Hey Digger,

                  I appreciate all your help!

                  I posted a photo of the headers a second ago and called them intakes and had to delete the message before anyone saw it I hope :-) LOL.

                  Anyway, here's the intake side of the motor photo.

                  BTW, I used a mirror and was able to confirm the casting on the other side of the head was 1264200 so a "200" head.

                  Thanks,
                  Bang
                  Attached Files
                  Own:
                  2009 335i Sedan - Silver with Black Interior
                  1990 325i Sedan - Black with Tan Interior

                  Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

                  Comment


                    #10
                    how high does it rev?

                    m20b25 is ~6250
                    normal eta is like ~4800
                    supaeta is somewhere in the middle - ~5200?

                    unless you have a bastardised ECU system, in that case this probably wont help anyway.

                    Comment


                      #11
                      yeah eta head, m20b25 intake, last piece is what bottom end....
                      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

                      Comment


                        #12
                        looks like your intake manifold is original "i", not eta. Like digger said, eta head is no go with i pistons and I don't see why someone would go through the trouble of installing eta pistons in B25 block. Someone just dropped eta engine/head into your "i" car, everything else is still "i".
                        If his ECU is still original, it will rev like "i", although I would be hesitant to do it with stock eta head.

                        Comment


                          #13
                          yes, my money is on eta long block caus it was cheaper when the t-belt broke on the original m20b25. all the other stuff (intake, exhaust, ECU , oil cooler, cooling system etc will be m20b25
                          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

                          Comment


                            #14
                            So, I guess the good news may be that I'm a prime candidate for a 2.7l stroker :-)

                            Is the only way to really verify the block to pull the intake manifold and look at the numbers on the driver side of the engine?

                            My personalized Florida plate for this car is E30 RSCU and I'm clearly rescuing this thing.

                            Thanks for all the help identifying the engine!
                            Own:
                            2009 335i Sedan - Silver with Black Interior
                            1990 325i Sedan - Black with Tan Interior

                            Restoring the e30 with 13 and 16 year old sons, started restoration in November 2015.

                            Comment


                              #15
                              Originally posted by Bangalorre View Post
                              So, I guess the good news may be that I'm a prime candidate for a 2.7l stroker :-)

                              Is the only way to really verify the block to pull the intake manifold and look at the numbers on the driver side of the engine?

                              My personalized Florida plate for this car is E30 RSCU and I'm clearly rescuing this thing.

                              Thanks for all the help identifying the engine!
                              It doesn't really matter if it's eta block, sort of. If it's 200 head, those are eta pistons and very likely eta block as a result. Good news indeed: if you want to stroke it to 2.7, it will cost you zero $ and zero time since it's already 2.7 :D.

                              Comment

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