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    #91
    Question: when piecing it all back together, what does it mean if while tightening the drivers side (pinion side) flange (#4 here) the input is easy to turn except for one small section, maybe 3 or 4 teeth on the pinion gear?

    Then, if the flange is tightened snug, everything locks up and it can't be turned by hand?

    I'm guessing this is that precision shimming aspect that is talked about. However, the clutches were the only thing changed, and everything went back on its respective side. Of the six bolts for the flange, I am able to properly torque down the forward most (input side) 2 bolts and it still turns smoothly with just a tiny bit of lash. The problem lies in tightening the rear most bolts anything more than finger tight.

    Is there a likely thing (or set of things) that I could have done wrong on reassembly that would have this effect? I measured the shims, and the thicker shim is on the pinion (problem) side. I believe this means that I didn't mix the shims up.

    I'm also not sure mechanically what it means that- as it gets tighter, the resistance starts with a few teeth and lack of backlash. Doesn't this mean that the pinion gear is crooked? Or is there another explanation?

    Edit: I just watched a video on setting up diff backlash, preload, and contact patch. I'm a rather visual person :)
    This combined with loosening the non-pinion side and still having an issue leads me to believe that the resistance is caused by negative lash and binding of the pinion gear, instead of preload. Is that summation correct?
    Last edited by Earendil; 02-25-2013, 01:15 PM. Reason: Tested a few more things, modified accordingly.
    -------------------------------------------------
    1989 - E30 - M20B25 - Manual. Approx 300,000+ miles - Track Rat & Weekend Fun
    2000 - E46 - M52TUB28 - Manual. Approx 130,000 miles - [not so] Daily Driver

    sigpic

    I'm looking for a Lachssilber Passenger Fender and Hood. PM if you have one or both to sell!

    Comment


      #92
      Can you discuss a bit about the Z3 Torsen Units. I'm thinking of replacing my 3.25 LSD on my S50 car with a 3.15 Torsen from a Z3. From what I've read, it seems like it's superior at putting power to the ground so long as you're not lifting a drive wheel or stuck in the snow. For a weekend/good weather street car, would a torsen be a better way to go? Also, I believe the Z3 diff will drop right out of the Z3 and straight into the E30, correct? Lastly, what fluid would you recommend for the Z3 torsen unit?

      Thanks!!

      Comment


        #93
        deleted
        Last edited by Wanganstyle; 09-09-2020, 04:51 PM.
        OBD1 M54/M52TU swap as a M50b25

        Z4 non powered steering rack fits e30



        Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

        Comment


          #94
          Originally posted by Wanganstyle View Post
          I like lubo moly 75-90 for bmw oem lsd units with no additives.

          Spec e30 rules has a oem diff static lockup test method and you can do similar for a diff on the ground.

          Fix the imput pinion and one output shaft to not move: then put some bolts in the other shaft and apply torque- a good stock diff shouldn't break free easily with human force applied: a dead one will give way internally
          Thanks for both tips!
          My E30 v1.0 | v2.0 | v3.0 | My E28 |My E34 | My feedback

          Comment


            #95
            Originally posted by Wanganstyle View Post
            An Open diff with giant hoosier tires on the ideal surface will have as much grip for an underpowered car as the torsen, clutch lsd units will :)
            If you don't have a wheel spin problem with an open diff, you don't need an LSD!

            Comment


              #96
              deleted
              Last edited by Wanganstyle; 09-09-2020, 04:51 PM.
              OBD1 M54/M52TU swap as a M50b25

              Z4 non powered steering rack fits e30



              Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

              Comment


                #97
                Originally posted by Earendil View Post
                Question: when piecing it all back together, what does it mean if while tightening the drivers side (pinion side) flange (#4 here) the input is easy to turn except for one small section, maybe 3 or 4 teeth on the pinion gear?

                Then, if the flange is tightened snug, everything locks up and it can't be turned by hand?

                I'm guessing this is that precision shimming aspect that is talked about. However, the clutches were the only thing changed, and everything went back on its respective side. Of the six bolts for the flange, I am able to properly torque down the forward most (input side) 2 bolts and it still turns smoothly with just a tiny bit of lash. The problem lies in tightening the rear most bolts anything more than finger tight.

                Is there a likely thing (or set of things) that I could have done wrong on reassembly that would have this effect? I measured the shims, and the thicker shim is on the pinion (problem) side. I believe this means that I didn't mix the shims up.

                I'm also not sure mechanically what it means that- as it gets tighter, the resistance starts with a few teeth and lack of backlash. Doesn't this mean that the pinion gear is crooked? Or is there another explanation?
                I found a solution, that might also be the cause. I've disassembled and re-assembled the diff 4 or 5 times now, so we'll dismiss the possibility that I just tightened something different this time.

                I removed the entire center stack and tried to assemble based on the advice of the ever-amazing Wangastyle, and everything torqued up just fine, without resistance. It would seem that my center stack is too thick, and this might be causing some sort of warping of the stack, even though the allen bolts tightened down without leaving a perceivable gap.

                Lessons learned.
                -------------------------------------------------
                1989 - E30 - M20B25 - Manual. Approx 300,000+ miles - Track Rat & Weekend Fun
                2000 - E46 - M52TUB28 - Manual. Approx 130,000 miles - [not so] Daily Driver

                sigpic

                I'm looking for a Lachssilber Passenger Fender and Hood. PM if you have one or both to sell!

                Comment


                  #98
                  Originally posted by Wanganstyle View Post
                  Lots'o good friggen info coming out of this one
                  So wait.. You're telling me torsen diffs aren't the be all-end all performance mods for the rear diff choice?
                  For a trackable street car, I'd still want a clutch based LSD?

                  Comment


                    #99
                    deleted
                    Last edited by Wanganstyle; 09-09-2020, 04:52 PM.
                    OBD1 M54/M52TU swap as a M50b25

                    Z4 non powered steering rack fits e30



                    Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

                    Comment


                      Question about identifying sounds made by the differential after a rebuild, and quite possibly related to the additional material inside the clutch assembly causing increased lockup.

                      Driving in A:
                      • Straight line: No noise.
                      • Tight circle slowly: mild rubbing/slipping sound (does not sound damaging)
                      • Tight circle quickly: no change from above.
                      • Driving in loose circle slowly: Metal popping sound. If I didn't know better I'd say it was a U-Joint binding and letting go.
                      • Driving in loose circle quickly: Metal popping sound starts to go away above 20mph.
                      • Straightening wheel from loose circle to straight: Metal popping sound for a few seconds after the wheel is straight, and then goes away.


                      Tight = Wheel lock.
                      Loose = half a steering wheel turn.
                      Fast = On edge of losing grip, unless speed stated.
                      Slow = Jogging pace

                      At speeds over 20mph I can hear nothing. The rubbing/slipping sound might get drowned out by road noise, but the metal popping sound couldn't be drowned out by anything but a piston deciding it wants to see the outside world.

                      Is this what a overly locked diff sounds like? Or could something else be going on internally?
                      -------------------------------------------------
                      1989 - E30 - M20B25 - Manual. Approx 300,000+ miles - Track Rat & Weekend Fun
                      2000 - E46 - M52TUB28 - Manual. Approx 130,000 miles - [not so] Daily Driver

                      sigpic

                      I'm looking for a Lachssilber Passenger Fender and Hood. PM if you have one or both to sell!

                      Comment


                        Are your tires hopping/scrubbing?

                        Sent from my GT-N7100 using Tapatalk 2
                        OBD1 M54/M52TU swap as a M50b25

                        Z4 non powered steering rack fits e30



                        Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

                        Comment


                          Originally posted by Wanganstyle View Post
                          Are your tires hopping/scrubbing?

                          Sent from my GT-N7100 using Tapatalk 2
                          Really hard to tell. dry pavement has been spotty at best around here recently, and my tires are into the nasty rubber until I can get an alignment and get the new rubber on. Certainly they aren't "hopping" like one feels in a locked 4x4 on dry pavement.
                          -------------------------------------------------
                          1989 - E30 - M20B25 - Manual. Approx 300,000+ miles - Track Rat & Weekend Fun
                          2000 - E46 - M52TUB28 - Manual. Approx 130,000 miles - [not so] Daily Driver

                          sigpic

                          I'm looking for a Lachssilber Passenger Fender and Hood. PM if you have one or both to sell!

                          Comment


                            Originally posted by Wanganstyle View Post
                            Are your tires hopping/scrubbing?

                            Sent from my GT-N7100 using Tapatalk 2
                            Originally posted by Earendil View Post
                            Really hard to tell. dry pavement has been spotty at best around here recently, and my tires are into the nasty rubber until I can get an alignment and get the new rubber on. Certainly they aren't "hopping" like one feels in a locked 4x4 on dry pavement.
                            I'm going to say that they have to be scrubbing some. I jacked up one of the back wheels, put the car in neutral, and applied a torque wrench to the axle nut to see when it would break away. I know this won't give me an absolute number, but it'll give me a comparitive number since the SpecE30 racing class tests "stock" diffs at 65ft/lbs using this method. Mine didn't brake away until around 125 ft/lbs give or take. Youch!

                            So for anyone that has driven a high locking diff, do you ever hear sounds that are more metallic in their sound? Or do you only hear increased "whurrr" from the clutches, and rubber/pavement popping/hopping?
                            -------------------------------------------------
                            1989 - E30 - M20B25 - Manual. Approx 300,000+ miles - Track Rat & Weekend Fun
                            2000 - E46 - M52TUB28 - Manual. Approx 130,000 miles - [not so] Daily Driver

                            sigpic

                            I'm looking for a Lachssilber Passenger Fender and Hood. PM if you have one or both to sell!

                            Comment


                              deleted
                              Last edited by Wanganstyle; 09-09-2020, 04:52 PM.
                              OBD1 M54/M52TU swap as a M50b25

                              Z4 non powered steering rack fits e30



                              Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

                              Comment


                                For a street driven car that is set up for autox and light track day usage, would you recommend a 4 clutch 60% lockup OEM unit over the OEM 25% unit?

                                What sort of change in handling characteristics would come as a result of switching to the 60% lockup unit?
                                Originally posted by priapism
                                My girl don't know shit, but she bakes a mean cupcake.
                                Originally posted by shameson
                                Usually it's best not to know how much money you have into your e30

                                Comment

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