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OEM v. Delrin v. Polyurethane Alternator Bushings

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  • OEM v. Delrin v. Polyurethane Alternator Bushings

    My OEM alternator bushings are worn and needing replacement. I've got a high mileage (but rebuilt) engine with 193K on the odometer (roughly 20K on the rebuild). The car is exclusively a street car. Turner offers them in polyurethane and AKG offers them in delrin. Is there any advantage of one set-up over another? Thanks.
    Jack
    Arlington, TN

    1990 BMW M3 - Diamantschwarz/Black

  • #2
    Just from my own experience, I ended up using OEM after trying Poly bushes. My car was an everyday street car and with the poly bushes the alternator tensioner arm snapped twice, so I ended up going back to the standard ones and they worked fine.

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    • #3
      I used Polyurethane bushings with a reinforced adjustment arm because they often will deform and eventually brake anyway even with stock bushings over time. I wouldn't use delrin.
      Last edited by Reelizmpro; 04-14-2009, 08:01 AM.

      88 M3 - LACHSSILBER/M TECH
      89 M3 - ALPINEWEISS II/SCHWARZ
      85 323I S52 - ALPINEWEISS/SCHWARZ
      91 M TECHNIC TURBO - MACAOBLAU/M TECH


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      • #4
        I put these in not to long ago. My stock ones were shot and the whole alternator was leaning.
        http://www.turnermotorsport.com/html...=ALT%20BUSHING
        @slowprogress

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        • #5
          I use stock, if it takes another 15 years before they wear out again, that's fine with me

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          • #6
            Originally posted by BingM3 View Post
            I use stock, if it takes another 15 years before they wear out again, that's fine with me
            Me too


            www.JOEBMWMotorsport.com
            JOEBMWMotorsport
            E30 M3 Rebuild Thread
            BMW & E30 M3 Parts and Services Specialist

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            • #7
              +1 for stock for street driven cars.



              - Tire is the other control arm bushing.

              zhpregistry.net

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              • #8
                I used the poly bushings after my stock wore out, within 2 years it broke the arm. I now have the Delrin AKG (white) bushings and I've experienced a broken top bolt... I can't say it's the culprit but...

                Lesson learned: If it ain't broke, don't switch it.
                Rich!

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                • #9
                  I replaced my oem bushings after 20k miles of use and they still looked good. I out new OEM bushings in.

                  - gabor
                  October 1987 build date.

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                  • #10
                    I like solid IMO. With the delrin, the alternator can't "lean" anywhere. The top mount should fit so flush it can only pivot up and down for adjustment. I made my own adjuster bracket out of a modified M10 one. Now the only downside to a solid mounted one is you must have a little slack/give in the belt. Make sure proper tension, or it can ruin the water pump nose bearing pretty fast. Once it's set right your good to go.

                    I can't see how anyone can use the stock bushings when flogging the car hard. I tried them with a new alternator from BMW since it came with them already installed. New bracket too, it still leaned enough to bother me after a couple weeks. Took alternator off, yup the bushings already showed oblong holes with compression on one side. One less thing to re-engineer marked off the list.
                    Photos

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                    • #11
                      Fuck, just went for poly on mine... Maybe I just need to buy stock ones then and new adjustment arm as well!
                      1987 BMW M3 E30

                      S50B32 swap thread http://www.s14.net/forums/showthread.php?t=43515

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                      • #12
                        Doesn't Bosch offer some stiffer white bushings? How do these compare to the red poly bushings that Turner sells?

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                        • #13
                          Hi is exclusively street. Also I noticed that people tend to over tighten the alternator belt which makes the whole unit lean that much more.

                          Originally posted by autox320 View Post
                          I like solid IMO. With the delrin, the alternator can't "lean" anywhere. The top mount should fit so flush it can only pivot up and down for adjustment. I made my own adjuster bracket out of a modified M10 one. Now the only downside to a solid mounted one is you must have a little slack/give in the belt. Make sure proper tension, or it can ruin the water pump nose bearing pretty fast. Once it's set right your good to go.

                          I can't see how anyone can use the stock bushings when flogging the car hard. I tried them with a new alternator from BMW since it came with them already installed. New bracket too, it still leaned enough to bother me after a couple weeks. Took alternator off, yup the bushings already showed oblong holes with compression on one side. One less thing to re-engineer marked off the list.



                          - Tire is the other control arm bushing.

                          zhpregistry.net

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                          • #14
                            Originally posted by ColinM View Post
                            Doesn't Bosch offer some stiffer white bushings? How do these compare to the red poly bushings that Turner sells?

                            Apparently this knowledge has not gotten to this group from the E30 M3 SIG.

                            The Bosch White bushings are best.... They are something on the order of $5-10 apiece (qty 4) but they are firmer than the OE bushings, which eventually wear and fail, and WAY better than the red polyurethane bushings which are too stiff and transmit too much vibration and cause bolts to break and fail. They are also not difficult to install, whereas the red poly bushings are a PITA.

                            OE (black) - too soft.... poly(red)... too hard.... Bosch (white)... just right!

                            Bosch number is 1 120 323 001 for the large, 1 120 323 002 for the small. E30 M3s need 4 large


                            I've used all three.... I broke a TON of alternator bolts (6-10) and even had an alternator fail (it basically got shaken to death) when using the red bushings... I have not had any issues with the white delrin bushings in several years of track use. For a gently driven street car, the stock ones will be fine... For a car that sees a lot of high rpm use, don't mess around with the red ones.
                            Last edited by M3 Adjuster; 04-15-2009, 03:23 AM.
                            Mark Williams
                            Dallas, TX

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

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                            • #15
                              Bushings

                              Hello:
                              Can these Bosch bushings be purchased at the dealer?

                              Chicco

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