M20 2.7i NA stroker build

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  • MWe
    Noobie
    • Feb 2026
    • 8

    #1

    M20 2.7i NA stroker build

    WORK IN PROGRESS

    Here's a description of the history from my project car and the build process to get the stroker running.

    Beginning 2009
    18 years old, just got my driver's license and was looking for my first car, I always had a week spot for e30's but was also considering the mercedes 190, vw corrado, Audi quatro.
    I was not very technically handy during that period but had some friends who were and a dad who's job it is to fix mechanical things, so enough support from that side to buy and fix/maintain an older car.
    Eventually decided to choose for an e30 316i, a friend had the same car and I liked how it handled.
    Looked and test drove an 316i shitbox with a worn cam first, I was pleased, but was immediately warned that it would be a financial disaster by my dad and friends.
    Later my mom found a car on the internet, a 1991 316i edition with around 190k km on the odometer, we went over there, looked at the car that had been sitting still for around 3 months, car was covered in bird shit, weeds growing underneath, brakes were stuck.
    Somehow the car started right away, only took some extra effort to get the brakes to release.
    After a few kilometers during the test drive the car started to drive as it should so at that point my dad got out and I was allowed to take the car for a test drive.
    Car seemed fine to me, so I bought the car and that was the start of this project.

    Click image for larger version  Name:	IMG_1941.jpg Views:	0 Size:	153.3 KB ID:	10167811

    2009-2026
    316i edition m40b16

    The car I bought is an edition version, so special upholstery, sport steering wheel and the black trim above the front window but this one without the check control panel.
    Exterior colour is sterling silver with 14 inch bottle caps wheels.
    First day I had the car we discovered that an immobilizer was installed, took around a week to find this out, but during this ' problem solving' I had the opportunity to inspect everything on the car.
    During this period the car was driven daily.
    Learned to wrench and do maintenance.
    Lowered the car with some unknown springs and a mix of Koni and Billstein dampers.
    Tested a Remus sport exhaust, just made a lot of noise and and felt like probably less power.
    No major breakdowns during this time, but basically changed out every component at least once.

    During this period I did have the opportunity to drive multiple engine configurations in the e30.
    M50b25, m20b25, m10b18 and an m30b34. I've never tested the m42 engine in a e30 but experienced this one in a e36.
    After testing a 6 cilinder I already decided to go that direction, choice was between the m50 and m20, but in my opinion the m20 sounds better although it has less power,
    Managed to make some movies of these cars as well with a GoPro:


    Eventually managed to find an engine somewhere for a low price, they tied me it was in good shape and came out of a running car so I assumed this was ok.
    The engine was an m20b25 with gearbox, cable loom and some extra parts.
    Bought the engine and put it in storage.

    Click image for larger version  Name:	IMG_7582.jpg Views:	0 Size:	280.9 KB ID:	10167812

    Eventually started rebuilding the m20-engine but was still driving in the m40.
    When the engine was already rebuild I tried to get the 316i to 316000 km, unfortunately the odometer broke down first, so I ordered some replacement parts and fixed the gears.

    Before I had to chance to reach the 316k the differential failed, so instead of getting a new differential I started the swap because I needed a different one for the m20 engine.

    Next posts will be about the the disassembly of the m20 and the rebuild process.
    Attached Files
    Last edited by MWe; 10-04-2026, 03:21 PM.
  • MWe
    Noobie
    • Feb 2026
    • 8

    #2
    Click image for larger version

Name:	IMG_1941.jpg
Views:	31
Size:	153.3 KB
ID:	10167831

    During this period I did have the opportunity to drive multiple engine configurations in the e30.

    M50b25, m20b25, m10b18 and an m30b34. I've never tested the m42 engine in a e30 but experienced this one in a e36.

    After testing a 6 cilinder I already decided to go that direction, choice was between the m50 and m20, but in my opinion the m20 sounds better although it has less power,

    Managed to make some movies of these cars as well with a GoPro:

    m40b16 : [YOUTUBE]

    m50b25 :
    ">
    " type="application/x-shockwave-flash" width="425" height="350">


    m30b34 :
    ">
    " type="application/x-shockwave-flash" width="425" height="350">





    Eventually managed to find an engine somewhere for a low price, they tied me it was in good shape and came out of a running car so I assumed this was ok.

    The engine was an m20b25 with gearbox, cable loom and some extra parts.

    Bought the engine and put it in storage.

    Click image for larger version

Name:	IMG_7582.jpg
Views:	30
Size:	280.9 KB
ID:	10167832

    At some point I started rebuilding the m20-engine but was still driving in the m40.

    When the engine was already rebuild I tried to get the 316i to 316000 km, unfortunately the odometer broke down first, so I ordered some replacement parts and fixed the gears.

    Before I had to chance to reach the 316k the differential failed, so instead of getting a new differential I started the swap because I needed a different one for the m20 engine.



    Next posts will be about the the disassembly of the m20 and the rebuild process.

    Comment

    • MWe
      Noobie
      • Feb 2026
      • 8

      #3
      Started dismantling the engine, took my time because I didn't had knowledge of this engine so it involved taking a lot of pictures.
      Click image for larger version  Name:	234B2646-958A-426C-BEE0-05B05A31CD67.jpg Views:	0 Size:	231.5 KB ID:	10167882
      Eventually I got the head off, and while disassembling the head I noticed a lot of scoring on the camshaft.
      Also one piston had pitting.
      Click image for larger version  Name:	832965CB-D4DD-4722-9018-6FBCA393840F.jpg Views:	0 Size:	155.0 KB ID:	10167883
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      Seeing this I already knew I had to get a new camshaft and new rocker arms.
      Not really a problem, I wanted to upgrade these anyway.
      The next inspection did however tore a larger gap in my budget.
      Click image for larger version

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      Cracked head between cilinder 5 & 6.
      So a lot of detonation was going on for a short period of time it seems.
      The whole piston top melted away, luckily only from cilinder 6.



      Rest of the engine seemed fine, so I was looking for parts at this point.
      Last edited by MWe; Yesterday, 01:23 PM.

      Comment

      • MWe
        Noobie
        • Feb 2026
        • 8

        #4
        Here are some extra pictures from the disassembly process:
        Click image for larger version

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        Click image for larger version

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        Click image for larger version

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        Some scoring on the cilinder walls:
        Click image for larger version

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        Comment

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