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2.5 Engine Build Project

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  • 2.5 Engine Build Project

    Hi all,

    I have a 2.5 build in progress and thought I'd share it with the forum. It began with the purchase of an M3 last November. A week later it spun a rod bearing. I was going to build a 2.5 anyway so no big deal. Basic spec is as follows:

    - CR: 11.5 - 11.7
    - Cams: Schrick 292/284
    - Intake: Testing between 48mm & 49.5mm (TB's & CF aibox)
    - E-Ticket Motorsport 30mm street head
    - 50/50 non-cat header and custom exhaust

    From this I expect something around 275hp. I'll explain the details futher as the story goes.

    Here is a video I made of the engine noise caused by the failing rod bearings.

    http://www.youtube.com/watch?v=zG0xfsGBPHw

    And the initial findings after the engine was pulled.

    http://www.youtube.com/watch?v=qsmisZQRXm0

    Here's a pic of the #1 rod bearing as it came out.








    The rod was not over heated, but the rotation of the bearing in the rod damaged the surface enough that it should be reworked.

    Cause was prolonged storage with old oil. Moisture got to the bearings and pitted them. It took several days for it to become apparent, but initially there was no indication.

    I'll stop for now and begin providing updates as I go along.

    Jake

  • #2
    Will be very nice when you are done. Hopefully you will get dyno measurements? It sounds like you are sticking with the stock rods. I know they are good quality from factory and that they were not overheated when the damage was done, just wondering why you are not "upgrading" the rods considering all the other upgrades you are doing?

    Comment


    • #3
      This is like a reminder to change your fluids after winter storage. Oil, brake fluid,.....
      Also a reminder that it is a good idea to start the car and warm it up during the winter whenever you have the chance. How long was the car stored?

      water is heavier than oil and brake fluid and when allowed will pool and cause problems.

      I am also in a rebuild so I will love to watch your progress. I like the 292/284 cams
      1989 e30 m3 Zinnoberrot/Grey 256k Track/M3T
      1991 e30 m3 Alpinweiß/Schwartz 81k Garage Queen
      1991 325iX Diamantschwarz/M-Tech 110k Snowmobile (For Sale)
      1991 325ic Macau Blau/M-Tech 178k M-Tech Cabrio 5spd (For Sale)
      2002 Chevy 2500HD 8.1 Vortec, Alison Tranny, 4.10 gears

      Comment


      • #4
        Hi mm1854. The spec list above only covers the basic dimension specs but not all the components to be used. The rods are from Arrow, valvetrain from Supertech, and pistons from JE. Guess I could have just included that in the list.

        I was going to describe them further at each stage of prep. There will be a write up on piston prep, head prep, block prep, oil pump prep/modification, dialing in the cams... etc etc...

        Jake

        Comment


        • #5
          Originally posted by junkyard_sal View Post
          How long was the car stored?
          Hi Sal. According to the previous owner it sat in storage for 2 years.

          Jake

          Comment


          • #6
            Glad to finally see an update Jake. Hope your engine project goes well! IIRC, you also have a 2.7l crank from John J. Is that for yet another project? Also, do you plan to use shim under buckets? FWIW, I think that shim under isn't really necessary (after much research of course) and don't plan to use them with my BMW MS cams (304A/316E).

            Warmest Regards,
            Erik
            Last edited by The///MadCircle; 04-07-2010, 05:24 AM.

            Comment


            • #7
              I believe that the oil and filter should be changed and the car run for a couple of minutes, then stored.
              This will allow non acidic fresh oil to flush the old acidic oil out and replace it.

              m

              Comment


              • #8
                hi jake



                From this I expect something around 275hp. I'll explain the details futher as the story goes.

                this is at the crank or the rear wheels

                and why a 30,5 mm cilinderhead
                and not a 29,5mm cilinderhead ??



                greetings dave

                Comment


                • #9
                  Originally posted by The///MadCircle View Post
                  Glad to finally see an update Jake. Hope your engine project goes well! IIRC, you also have a 2.7l crank from John J. Is that for yet another project? Also, do you plan to use shim under buckets? FWIW, I think that shim under isn't really necessary (after much research of course) and don't plan to use them with my BMW MS cams (304A/316E).

                  Warmest Regards,
                  Erik
                  Hi Erik,

                  Yes, the 2.7 crank is for a different project. That one probably won't surface for a few more years. And I am using Arrow shim under buckets. Not totally necessary but it's good practice.

                  Originally posted by davem3 View Post
                  hi jake



                  From this I expect something around 275hp. I'll explain the details futher as the story goes.

                  this is at the crank or the rear wheels

                  and why a 30,5 mm cilinderhead
                  and not a 29,5mm cilinderhead ??



                  greetings dave
                  Hi Dave,

                  That figure is at the flywheel.

                  Mario Rigoli (E-Ticket Motorsports) offers 2 standard head specs, street @ 30mm and race @ 30.5mm. But don't get too focused on exact size as port shape is another factor. A 29.5 head from Moufang (via John) would have worked well here too. But Mario is close to me and puts out a very good product and I don't do business with John any more.

                  Jake

                  Comment


                  • #10
                    Jake,

                    Is this for a street car or a track car? I'm assuming the E-Ticket 30.5mm race head has a port shape more appropriate for higher rpm use which would make it less appropriate for a street / dual purpose car?

                    Also, when you get to writing something on cam setup, I still have a cleaned up copy of what Jefrem wrote if it helps as a starting point.

                    Subscribing...

                    Brendan
                    sigpic
                    Track Car Build | COM Sports Car Club

                    Comment


                    • #11
                      looking forward to seeing this come together.
                      Mark Williams
                      Dallas, TX

                      Nothing says "welcome to the neighborhood" like a search... oh wait... looks like they are all gone! :rastajake:

                      sigpic

                      Comment


                      • #12
                        Originally posted by Brendan View Post
                        Jake,

                        Is this for a street car or a track car? I'm assuming the E-Ticket 30.5mm race head has a port shape more appropriate for higher rpm use which would make it less appropriate for a street / dual purpose car?

                        Also, when you get to writing something on cam setup, I still have a cleaned up copy of what Jefrem wrote if it helps as a starting point.

                        Subscribing...

                        Brendan
                        Hi Brendan,

                        This is for a daily driven street car. As for E-Ticket's race head, I assume the profile is designed for a more aggressive build. Hard to say more than this as I've not tested them personnally. Maybe Matt or Mario himself will provide comment.

                        And thanks for the offer on the cam setup! I'll surely take you up on that when the time comes.

                        Jake

                        Comment


                        • #13
                          Lunch break...

                          I started with piston prep. These started as Grp A replica's from JE which have had the dome removed to reduce CR to the target 11.5 - 11.7. From the machinist they came mostly prepped. There was some minor edges left in the very corners of the valve pockets so I spent a few hours removing them.

                          Here is a picture of one as it came from the machinist.






                          This one shows where the minor finishing was focused.






                          And after a quick buff with some super fine steel wool. All the edges have a nice consistant radius with no sharp edges to create hot spots.






                          With mostly finished pistons it was time to do a mock build-up to confirm clearances and volumes.

                          First I made some leveling legs for the block itself as it needs to be leveled while measuring piston volumes. They're just simple bolts that have had the heads slightly rounded. This is done to help ensure smooth leveling adjustments, otherwise the bolt head would dig into your work surface.






                          I use four of these bolts and adjust level as follows:






                          I use a basic precision level.






                          Then I set up the glass burette and preparred to CC the piston tops.






                          I CC the piston tops by putting the piston at a predetermined distance in the bore, measuring volume to the top of the bore, and then comparring that number to the calculated volume for that given stroke.

                          So for example, if I measure 29cc and the calculated volume for 3mm of stroke is 21.3cc, I take measured volume and minus the calculated volume. In this case the result is 7.7cc. If the piston had a large pop-up dome you could get a negative number as the dome takes volume away.

                          This measurement represents the volume caused by piston dish, dome, and/or valve pockets and it must be added to the overall TDC combustion chamber volume when computing CR. I'll give actual readings later today.

                          Here are some additional pictures.

                          With the piston approximately 3mm down the bore, a volume measurement is started.






                          After the volume measurement is attained, the fluid is evacuated and then a dial indicator is positioned at piston center and remaining up-stroke to TDC is precision measured by rolling the crank until the piston stops moving.






                          In this case total piston upward movement measured out to 3.17mm. Using the following formula you can now find the calculated volume.

                          (Pi * r² * height) / 1000 = CM³ (or "cc")

                          So 3.17mm on a 95mm bore equates to 22.47cc. The actual volume measurement averaged 30.2cc, so there is more actual volume than calculated. So you add this to the total TDC volume. In this case you're adding 7.73cc.

                          If this isn't totally clear let me know and I'll reword the process.

                          Something else to note, fluid does easily get past the rings while taking volume measurements. To prevent this put the piston at the bottom of the bore, then apply a very thin coating of vaseline to the bore. When you bring the piston up the bore the vaseline will seal up the gaps between the ring and the cylinder wall.

                          Be careful not to us too much though as this will affect your volume measurements. I put a 1" band around the bore and ensure there is no more on there than I can wipe off with my finger. You should NOT see it pile up on the edge of the piston as it comes up the bore. I predict there is 1 - 2 cc of volume between the piston crown and the bore. If you fill that up with vaseline your measurements will not be accurate.

                          Here is a quick picture attempting to show how much I used.






                          Jake

                          Comment


                          • #14
                            I love jake projects :nice!:


                            Originally posted by drinaldis
                            I dated a girl who used to do the reverse grind. I kinda liked it.

                            Comment


                            • #15
                              Great stuff Jake, I love following threads like this. With my build to start in the next 12 months this is compulsory reading.

                              Aaron :nice!:

                              "But most of all...
                              ... I like the way you move......"

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