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    Polyurethane motor mounts?

    Hello! I plan on replacing my motor mounts, as the passenger-side mount isn't exactly on speaking terms with the motor. It's just kind of sitting on it, off to the side. That said, I keep seeing polyurethane mounts for sale. How do they compare to the rubber ones, and should I consider picking some up?

    #2
    If the car is any sort of a street car I would not consider poly. There are HD rubber mounts available that give you the stiffness without the extra NHV, I’d snag those.

    I know there will be a line of folks who disagree, I just don’t feel like poly offers much of anything over a good rubber bush.
    1990 Brilliantrot 325iS, 3.1L M20 Build Thread
    1990 Brilliantrot 325iS, daily Build Thread
    1989 Zinnoberrot M3 Build Thread

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      #3
      Originally posted by AWDBOB View Post
      If the car is any sort of a street car I would not consider poly. There are HD rubber mounts available that give you the stiffness without the extra NHV, I’d snag those.

      I know there will be a line of folks who disagree, I just don’t feel like poly offers much of anything over a good rubber bush.
      I agree about poly. Had a bad luck with HD OEM e24 mounts. They are stiffer then stock and less pliable therefore get cracked/ripped easier than OEM. I would go genuine OEM with engine mounts for another 20 years of issue free service

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        #4
        OE m20 rubber engine mounts don't last anywhere near 20 years, and OEM ones are even worse
        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

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          #5
          Originally posted by digger View Post
          OE ...... don't last ..... and OEM ones are even worse
          my '90 mounts were still in one piece after 25+ years....ugly one piece but still together.

          What r u trying to say? isn't OE and OEM same thing?what do you run?

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            #6
            Quality OE mounts are fine for a street car that sees occasional road tracks, even. When my car was a daily driver, I drove it to the track for HPDE events for about 2 years. It had the same mounts that came with the car (PO replaced them about a year before), and they didn't break until I lent the car to my pops to do his first track weekend - he hit the guad rail at Sebring.

            The endurance race car had them for about 5 or 6 events (costs us modification points for solid mounts) until a driver hit a tire barrier at Daytona. That was about 6 hours into a 14 hour race, the fan hit the radiator (ultimately causing the engine to blow a HG much later). We would still be using rubber if it weren't for the fear of incidents. The solid mounts cost half the points of an aftermarket seat bar including heim joint adjustable links. Kinda backward rule IMO, sway bars decrease lap times far more than engine mounts.
            john@m20guru.com
            Links:
            Transaction feedback: Here, here and here. Thanks :D

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              #7
              Originally posted by zaq123 View Post

              my '90 mounts were still in one piece after 25+ years....ugly one piece but still together.

              What r u trying to say? isn't OE and OEM same thing?what do you run?
              OE is Original Equipment (or Equivient) OEM is Original Equipment Manufacturer (made by or sold by BMW themselves)
              john@m20guru.com
              Links:
              Transaction feedback: Here, here and here. Thanks :D

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                #8
                Originally posted by zaq123 View Post

                my '90 mounts were still in one piece after 25+ years....ugly one piece but still together.

                What r u trying to say? isn't OE and OEM same thing?what do you run?
                no OEM is different to OE. OE is the genuine BMW part, OEM means the manufacture makes OE parts but not necessarily the supplier for the original equipment of the part in question.
                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

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                  #9
                  It's so confusing. In the industry, OE is supposed to mean what came in the car from the mfgr as installed on the car when delivered. Once the part is replaced, it's not considered OE, even if the replacement part came from the auto maker. OEM means the same mfgr that made the original part makes the replacement (Febi, Bosch, Bher, Mhale, BMW etc). I tend to use OEM as the description for the part that is exactly the same as what was installed originally (NOT Rein, Uro, Elring etc)...

                  OEM stands for original equipment manufacturer. OE stands for original equipment. OE parts are the components of the vehicle as it's made in the factory – all of the original parts that the car was first built with. Once the car comes out of the factory, everything else is not an OE part.
                  Edit: So if I have it wrong, sorry, but to sway any confusion with clients, "aftermarket replacement" is the term I use.
                  john@m20guru.com
                  Links:
                  Transaction feedback: Here, here and here. Thanks :D

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                    #10
                    probably easier to say genuine BMW parts or aftermarket as that's what i'm referring to.
                    in the case of engine mounts the genuine are like $80 and the others about $8 and the genuine are much better. not 10x better but engine mounts are a PITA to change so you want the best and the lowest chance of delamination
                    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

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                      #11
                      I didn't notice much of an impact from switching from good condition stock engine mounts to 95A poly mounts. The car has a bit more vibration at idle, but otherwise it was indecipherable. It might also be because the rest of the car is already so "race car" that I just didn't notice (car is full poly or delrin everywhere in the suspension). I have heard that the trans mounts make a really big difference in NVH so I opted to run the thicker stock 23711175424 rubber mounts with a reinforcing cup and been pretty happy.

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                        #12
                        I second the 95A poly mounts. Did them with the manual swap along with poly trans. A tad more noise but nothing I can complain about. It does make the whole car vibrate at certain RPMs idk why (like 3700 is just a significant increase and then it goes away at 3800).
                        85% of the time i have no idea what I'm doing

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                          #13
                          Originally posted by digger View Post
                          OE m20 rubber engine mounts don't last anywhere near 20 years, and OEM ones are even worse
                          the originals on my 90 are still just fine. sent from hell using tapatalk
                          ~~~~~~~~~~~~~~~~~
                          '90 325i sedan daily driven
                          '85 325e coupe also a daily

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