Das Beast: My E30 track / street build

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  • dvallis
    E30 Fanatic
    • Oct 2015
    • 1472

    #271
    Dammit! Spreadsheet error. Thanks for the error check. We're both wrong though. Installed height should be same as original spring, which was 33 mm (1.299")

    So .... (1.825 - 1.299) in x 120 lb/in = 63 lb, but if you look at the spring data here, it shows 1.300" as 46 lbs. Quite a difference. Their data is weird though. Spring rate is not linear.

    I'll measure it tonight with a gauge and find out for sure.
    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

    1987 E30 3L Turbo Stroker Das Beast
    2002 E39 M5

    Comment

    • peterman
      Advanced Member
      • Feb 2015
      • 165

      #272
      The data may not be incorrect if it is a progressive spring which is likely the case. Considering that it is a valve spring, and is probably used in a DOHC 4 valve motor, the required holding force for valves is decreased drastically over that of a 2 valve motor. So there is probably a low k to help with the initial jerk of the cam and the low holding requirement (freeing up power to the wheels), then a larger k value to reduce valve float.

      Time to search mcmaster for an appropriate spring.

      Comment

      • dvallis
        E30 Fanatic
        • Oct 2015
        • 1472

        #273
        So, it's a progressive spring. The manufacturer's data for length and lbs show that rate increases with compression.

        Deleted psi data as its wrong. See posts below.

        Height Comp lbs Rate
        1.400 0.425 34 80
        1.350 0.475 39 82
        1.300 0.525 46 88
        1.250 0.575 51 89
        1.200 0.625 56 90
        1.150 0.675 62 92
        1.100 0.725 68 94
        1.050 0.775 74 95
        1.000 0.825 81 98
        Last edited by dvallis; 08-26-2016, 06:16 PM.
        "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

        1987 E30 3L Turbo Stroker Das Beast
        2002 E39 M5

        Comment

        • peterman
          Advanced Member
          • Feb 2015
          • 165

          #274
          What is the max allowable pressure on the turbo bearings? Are they journal or ball bearings? You certainly do not want to blow those seals.

          Comment

          • dvallis
            E30 Fanatic
            • Oct 2015
            • 1472

            #275
            Precision says 85 psi max for a journal bearing turbo with 4AN feed line. Mine is 3AN, so even better. Setup proven by Kameron.
            Last edited by dvallis; 08-26-2016, 06:14 PM.
            "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

            1987 E30 3L Turbo Stroker Das Beast
            2002 E39 M5

            Comment

            • dvallis
              E30 Fanatic
              • Oct 2015
              • 1472

              #276
              Zach, you're going to college for mechanical engineering, right? Should have caught this and called me out. :devil: We HAVE all the data to calculate oil pressure exactly with the new spring.

              Free length: 1.825"
              Installed height: 1.300"
              Rate: 88 lbs/in
              Diameter: 0.945"

              Pressure = compression x rate / area

              psi = lbs/in x in / in2 = lbs/in2

              Oil Pressure = (1.825-1.300)×88 / ((0.945/2)^2 x 3.1415)
              Oil Pressure = 66 psi

              Perfect.

              I'd say we engineered the he'll out of this enough. Spring goes in tomorrow so this build can keep moving.
              Last edited by dvallis; 08-26-2016, 09:17 PM.
              "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

              1987 E30 3L Turbo Stroker Das Beast
              2002 E39 M5

              Comment

              • peterman
                Advanced Member
                • Feb 2015
                • 165

                #277
                Originally posted by dvallis
                Z

                Free length: 1.825"
                Installed height: 1.300"
                Rate: 88 lbs/in
                Diameter: 0.945"

                Pressure = compression x rate / area

                psi = lbs/in x in / in2 = lbs/in2

                Oil Pressure = (1.825-1.300)×88 / ((0.945/2)^2 x 3.1415)
                Oil Pressure = 66 psi

                Perfect.

                I'd say we engineered the he'll out of this enough. Spring goes in tomorrow so this build can keep moving.
                Make sure you're using the working area of the valve, not the flange area (if there is one)

                Since you are adding another passage for the turbo you will effectively be lowering the idle oil pressure across the engine since your pump V dot does not change but bearing V dot decreases due a portion of it now going to the turbo. It may be negligible, but something to consider if you have low pressure at idle.
                Apparently the 524td engine used a higher flow pump 11411275093.

                A 3AN fitting will restrict flow to the turbo.

                If it is supposed to use a 4AN hose, you should probably supply enough oil for that hose.
                Cross sectional area (I think these numbers are correct, not possitive though)
                3AN = 0.0276 in^2
                4AN = 0.0491 in^2

                By using a 3AN fitting and hose you should have sufficient oil pressure, but you reduced oil flow by 50%! This has overheating implications since the fluid velocity will be slower to leave the working area of the turbo.

                edit: the oil flow will not be reduced by 50% but you will be requiring a higher exit velocity from the bearing orifices to maintain proper pressure. I would still be concerned about the possibilities of overheating the oil.
                Last edited by peterman; 08-27-2016, 06:28 AM.

                Comment

                • dvallis
                  E30 Fanatic
                  • Oct 2015
                  • 1472

                  #278
                  Weekend Update

                  So, in the end we decided not to do the oil pressure relief valve delete. The math made sense, spring rate was right when we tested it .... but there's enough invested in the engine that it's not worth the risk. We figure there's a reason they put a pressure relief valve in the pump and block. No sense blowing turbo seals and whatnot if the pressure is too high.

                  Moving on. We had to get the Lump off it's stand and back onto a hoist to install the new rear crank seal. Pretty easy when you use the motor mounts and a block lug as lift points. You forget how heavy this damn thing is. Electric hoist is handy.





                  Crank scraper and gasket going on. This takes patience. Stack up looks like:

                  OIL PAN
                  PERMATEX
                  CORK GASKET
                  PERMATEX
                  CRANK SCRAPER
                  PERMATEX
                  CORK GASKET
                  PERMATEX
                  BLOCK



                  Oil pump, scraper, and pressure relief valve in place.



                  Getting the oil pan bolts on was a PITA, given all the layers of cork and goop but it worked out. Block is sealed up. Ready to start bolting on the "fiddly bits".

                  "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                  1987 E30 3L Turbo Stroker Das Beast
                  2002 E39 M5

                  Comment

                  • dvallis
                    E30 Fanatic
                    • Oct 2015
                    • 1472

                    #279
                    Timing Belt Smackdown

                    Thermostatic valve. Before. Looking pretty ugly.



                    After a dunk in the parts washer, with heater core delete.



                    Timing belt installed. It was a one hour smackdown. Feels like I've been wrestling a gorilla. Once you figure out the method it's not too bad. (Hahaha. Sure)

                    1. Loosen tensioner bolts
                    2. Compress spring and tighten top bolt
                    3. Put first 5 mm only of belt on pulleys
                    4. Check timing marks
                    5. Dork with crank slightly to get slack on tensioner
                    6. Slide belt over tensioner last
                    7. Tighten bottom tensioner bolt, not all the way
                    8. Slack upper tensioner bolt to let spring expand
                    9. Tighten both tensioner bolts
                    10. Rotate crank clockwise. Check timing.
                    11. Realize you are one tooth off. Remove everything
                    12. Beer. And cursing. Re-apply mosquito repellent
                    12. Repeat. Until it works.

                    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                    1987 E30 3L Turbo Stroker Das Beast
                    2002 E39 M5

                    Comment

                    • Eric
                      R3V Elite
                      • Feb 2004
                      • 5138

                      #280
                      subscribed, great stuff!
                      My E30 v1.0 | v2.0 | v3.0 | My E28 |My E34 | My feedback

                      Comment

                      • jeffnhiscars
                        R3V OG
                        • Jun 2011
                        • 6010

                        #281
                        You want to rotate the crank (2 full turns btw) with the tensioner bolts loose
                        Seat Shocks....I have passed the baton to John Christy from Ninestitch. Email John or Garrett at ninestitch1@gmail.com

                        https://www.r3vlimited.com/board/sho...86#post4944786
                        Alice the Time Capsule
                        http://www.r3vlimited.com/board/showthread.php?t=360504
                        87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                        Comment

                        • digger
                          R3V Elite
                          • Nov 2005
                          • 5909

                          #282
                          have you use the correct mark on the gear for TDC iirc its not the 0 position of the vernier marks there is a separate single mark
                          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

                          • dvallis
                            E30 Fanatic
                            • Oct 2015
                            • 1472

                            #283
                            Yes. Aligned faint single diagonal mark on top right side of cylinder head with TDC on cam timing wheel. TDC mark on crank aligns with notch on lower cover.
                            "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                            1987 E30 3L Turbo Stroker Das Beast
                            2002 E39 M5

                            Comment

                            • peterman
                              Advanced Member
                              • Feb 2015
                              • 165

                              #284
                              Originally posted by digger
                              have you use the correct mark on the gear for TDC iirc its not the 0 position of the vernier marks there is a separate single mark
                              I think the Vernier marks are on the timing belt cover. Those should be used when checking the O|T mark on the harmonic balancer, correct?

                              Comment

                              • dvallis
                                E30 Fanatic
                                • Oct 2015
                                • 1472

                                #285
                                Timing marks are circled in red below.

                                "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                                1987 E30 3L Turbo Stroker Das Beast
                                2002 E39 M5

                                Comment

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