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Thread: SubFrame Bushing Information

  1. #1
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    SubFrame Bushing Information

    Correction! This washer appears to be an aftermarket part

    Subframe Bushing Information for the Group
    Now that more venders are getting into the market of supplying SubFrame bushings for the e30/Z3 I’ve noticed more and more issues for the less experience owners getting caught up with correct fitment. So lets get some information in one place
    It is easy to think the bushing is correct or installed properly and still have a serious flaw to the system. Not every aftermarket supplier engineers the bushing in question the same. The new kid in the mail room thinks the e30 bushings are the same as the z3 or even the entire staff could be mistaken and send incorrect parts. I got e30 bushings from Ireland one time and those guys know better. It seems to happen often even with the experience suppliers. So lets do a check list.
    The most important point is to be sure you have received the bushing for a z3. Not a e30.
    Check the length of the new bushing.
    Look at the top of the new bushing. Does it have a recess for the hex head portion of the stud. Most but not all urethane type bushing will have a recess in the upper section to make room for the hex head and still seat correctly against the brass colored seat section of the stud (Larger disc above the hex head on the stud). The inner metal tube of the all bushings will rest against the hex head and be flush on the bottom with the urethane portion of the part. If you got a wrong e30 bushing, you can cut the tube to the correct length and make a recess in the Urethane portion of the bushing to make fit, but you got to be perfect on the cut of the tube. It needs to be dead flat against the hex head or you will have static deflection of the bushing at rest.
    On the OEM bushing setup, there is a washer/spacer on top of the bushing. I think this is this “washer” that confuses a lot of guys. This washer takes up the space around the hex head portion of the stud, but is only used if the engineer who designed the aftermarket busing intended it to be so. Ireland and most Urethane bushings are designed not to use this washer. The purple bushing Power Flex produces appears from the picture to need the washer. I have never had a Power Flex bushing to confirm my suspicion. The Aluminum Bushing Turner produces, requires the washer.
    I suspect there may be owners changing out those bad green Urethane bushings produced about 10 years ago with Power Flex and not realizing they are missing that very important washer that supports the bushing from “rolling over” on the stud. I realized this when I received a new set of Turner Aluminum Bushings to replace a set of Ireland Reds. It took me a few minutes to recall that the OEM washer/spacer was sitting over in a leftovers box. Replacing that washer/Spacer filled the gap and makes a very rigid connection. Had I just slapped the Aluminum bushing on without looking at what was really happening, could have been a big problem over time. If the Power Flex design is as I think it is, I hope owners are aware of this and properly adding the missing washer if they are replacing an old Ireland bushing. Here are a couple shots for reference.

    Washer/Spacer in Question
    20180306_194017.jpg
    Rubber OEM Bushing without the spacer.
    This is the OEM design!
    Rubber Without Spacer.jpg
    Rubber with Spacer correctly in place.
    Rubber OEM.jpg
    Urethane without Spacer correct fit
    Urethane.jpg
    Aluminum with Spacer Correct Fit
    Alum w Spacer.jpg
    Last edited by PbFut; 03-12-2018 at 02:04 PM. Reason: Correction Washer is Aftermarket!
    Dan "PbFut" Rose

  2. #2
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    Good information. Thanks for the write up.

  3. #3
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    Is your information Z3M specific? I have never seen the washer/spacer on any of the Z3 (non-M) that I've worked on. They all look like your second photo (incorrect fitting) when they are installed.

    I have fitted Powerflex Purple bushings and there top section has a recess that allows the hex head to fit in and the bushing work against the large washer already on the stem. This top section allows for some limited compression/movement during use.
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  4. #4
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    Good to know about the Power Flex.
    As for the washer./spacer They were on my 99m but I did not purchase the car new.
    Curious if these are not OEM. I presumed they were as it seems odd for the bushing to be allowed to pivot against that hex head.
    Apparently the stud is strong enough to tolerate the stress and the washers I have are a aftermarket part????
    Dan "PbFut" Rose

  5. #5
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    That looks like this AC Schnitzer part.

    https://www.bimmerforums.com/forum/s...2#post29894602
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  6. #6
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    Holly Cow. How could these cars not have this part. No wonder the back ends rip apart.
    My apologies for the first post. I did not realize the part I had was aftermarket.
    Now for the next question. Why the hell are these not OEM?
    Dan "PbFut" Rose

  7. #7
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    Well that washer has BMW number engraved on it and it was available from BMW dealerships AFAIK for ACS suspension owners only.



    I have Powerflex bushes installed on my car and that ACS washer stored on a shelf (acquired it later). Should I install it? The last consensus I remember was that it's not needed for poly bushes...
    Last edited by deni2s; 03-12-2018 at 05:50 PM.

  8. #8
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    Per my original post, I have never had a PowerFlex in the my hand. A post below says the PowerFLex has the recessed area for the hex head. That indicates to me the Power Flex sits correctly tight to the mount like the Red Bushing in first post. If the PowerFlex sits like the Rubber Bushing, I would consider adding that washer.
    Dan "PbFut" Rose

  9. #9
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    I would really like some of those aluminum spacers... how hard would it be to reproduce those?

    On that note... how much does NVH increase with the fully aluminum mounts?

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  10. #10
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    I am not concerned about noise with the all aluminum bushing. Trust me, the LS motor and straight cut gears in the Jerico trumps all.
    As for creating these spacers. I am sure they would be super simple to do. I doubt if they have a patent.
    This might be a nice mid point between urethane and rubber.
    Kind of ripping off AC Schnitzer but previous post say they only provide if you use their spring and shock which is kind of chicken shit in my view. If there is real interest I could have a shop in town turn a batch for us.
    Has anyone tried to order using the BMW part number in the picture within this thread? Way easier then doing a batch at the local machine shop.
    Dan "PbFut" Rose

  11. #11
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    Here's a photo of the Powerflex bushings. The bottom section is just like a solid version of the OE bushing. The top section fills the gap and comes up to the fixed washer just above the hex head on the stem. It also compresses slightly when installed.
    Attached Images Attached Images
    Last edited by Muzz258; 03-14-2018 at 03:03 PM.
    1999 2.8L Z3 Roadster,
    2000 3.0L Z3 Roadster,

    There is only one thing more pleasurable than working on a Z3, that's driving it top down on a fine day.

  12. #12
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    Excellent info on the PowerFlex Bushing
    It appears the cup portion of the set is doing the same as this aluminum washer spacer in question.
    I dropped by a local aircraft/CNC shop today to inquire about making a batch of these washers.
    Initial indication is that the cost will be reasonable.
    Thankfully, this little area of Temecula has some decent racing and aircraft fabrication shops so it is easy to get stuff like this produced.
    Dan "PbFut" Rose

  13. #13
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    Hey Randy's
    If you see this, can you weigh in on this subject?
    If I am off base, we need to know.
    Dan "PbFut" Rose

  14. #14
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    I'm not a Randy, but I have an opinion:

    I don't see any market for these spacers now that the cars are all old. They are just a curiosity at this point. They offer no additional benefit that I can see above and beyond what a less compliant bushing with that upper mating surface already accomplishes. Let's go through this -- the issue is that the subframe can move relative to the mounting studs, right? There are three ways it can move:

    1) lateral movement of the subframe on the horizontal plane (not addressed with rubber+spacer)
    2) vertical movement of the subframe (addressed with top part of bushing plus "pushrod")
    3) twisting of the subframe around the studs (similar to #1, except that the spacer would help for this)

    So a stiff bushing addresses all three, where the spacer accomplishes only two. If the spacer mated cleanly with the hex shape of the stud, maybe it could do all three, but the ACS one didn't, as far as I can tell.

    Almost every Z3, at this point in time, needs new subframe bushings. If someone's going to go to the trouble to drop their subframe to install these spacers, wouldn't they also be willing to go the extra step to pull the old rubber bushings? I get that this is hard (after all, 12 years ago I nearly broke your bushing removal tool trying to remove mine) but it's a "once-you're-in-there" thing. Once you're in there, just use urethane, rather than new rubber plus an aluminum spacer. It's better.

    The only people for whom this would make sense are people who just recently replaced their subframe bushings with new stock ones, and I'd venture that there are approximately zero of those people who would even find out about the availability of this spacer.
    I like the unicorns.
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    '99 M Coupe - Estoril Blue/Black (1-of-82)
    '03 540iT - Sterling Gray/Black (1-of-24)
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  15. #15
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    Thanks for the input Josh
    I was thinking the same thing. Even though its a needed part, most enthusiast will opt for urethane. The ones that don't know this problem exist have the rubber bushing but will not know to fix.. So its not like a large number would be rushing to obtain.
    The shop said ~10 bucks a pop for 100 units. "Maybe slightly less" I guess we could call them Zcoin and hype up a bunch of fake demand stories.
    I'd be willing to front the cost and help those who need, but I don't think there are 50 users in need to recover the cost. Even at higher price and lower count, say 20 each and only make 50 units/ 25 sets, I don't think there are enough who would want. I'll let this die unless I hear otherwise. Hopefully we obtained a little more info on this questionable design.
    Dan "PbFut" Rose

  16. #16
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    Quote Originally Posted by PbFut View Post
    "Maybe slightly less" I guess we could call them Zcoin and hype up a bunch of fake demand stories.
    I bought those washers as a collectors item, knowing that they are not so easy to find. There are still some people around who want to keep 100% OEM car, but I think they will be interested in original ACS Zcoins, not the fake ones ;D.

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