motor mount - arms too narrow.

[jwetering]

So I ponied up the big bucks and bought OEM e30 m42 motor mounts because I could not get the e36 m42 motor mounts that RockAuto shipped me to fit to my satisfaction.

Well I will be damned though because these e30 mounts don't fit much better.

See the photos attached but when everything is torqued down and the mounts are seated properly in the subframe the holes in the arms are just too narrow to square up with the top pins on the mounts themselves. Both the passenger and driver side mounts are skewed right over.

Anybody ever seen this ?


I should mention this is an m42 swap into an early m10 car - but I changed the subframe after I blamed the original m10 subframe for not letting the e36 mounts fit.


Anyway - see the photos...

[bmwman91]

So you have an E30 subframe in the car now? If so, then things should fit fine. I assume you noticed alignment tabs on the bottom of the mounts, and the only thing I can think is that they are rotated 180 degrees, since the top post is off-center.

[jwetering]

So you have an e30 subframe in the car now? If so, then things should fit fine. I assume you noticed alignment tabs on the bottom of the mounts, and the only thing I can think is that they are rotated 180 degrees, since the top post is off-center.

The short story here is that it looks like I got dealt a set of defective OEM motor mounts. The top hats were turned 180 degrees so the pins were offset outboard rather than inboard. I have another set of OEM on the way - they should be here tomorrow. If those are also goofy then I already have a set of MTC aftermarket mounts lined up which I have put eyes on and which I know will work because the pin is indeed offset inboard.

The longer story is that I was initially working with an m10 subframe and a set of e36 motor mounts that RockAuto shipped instead of the e30 mounts they advertised. The early m10 e30 subframe is slightly different than the subframes installed in every other e30. First off there's a set of tabs to hold a small shock absorber and second off the holes for the bottom stud and locating dowel are a few mm farther apart so late model motor mounts won't fit without a little bit of filing.

The e36 mounts didn't work because the spacing between the stud and locating dowel on those was *way* too wide for the m10 subfarme. I filed out the subframe to make them seat but the top pins were way too widely spaced. Took me a while to figure out the problem was with the mounts and not my subframe.

That's when I said fk it and found a later model e30 subframe (cheap) and bought a set of OEM e30 mounts at big $. The mounts seated in the new subframe just fine, but imagine my frustration when the top pins were *way* too widely spaced for my motor. Took me a long tie to figure out thatthe mounts were defective. Not a lot of good photos of e30 motor mounts showing the offset (until now).

Anyway - here's aside view of the defective OEM mount (one of the ones installed in my original post). See how the top pin is located closer to the dowel ? I will post a photo of the correct mount tomorrow for comparison.

[Andre3127]

Grind the locating nub off and rotate them 180 degrees to fit.

[jwetering]

Grind the locating nub off and rotate them 180 degrees to fit.

Tried that.

In fact I could rotate my e36 mounts 180 degrees and the nub sat off the subframe perch even without grinding. OK- the top pins were still too wide for my arms. Sure I might have been able to stretch the mounts to fit but I'm no going for a bodge.

This simply did not work for me... unless you've actually seen it work yourself I'm going to have to say it's a myth.

[bmwman91]

Weird, I could see one of them being manufactured incorrectly, but both being that way seems unlikely. Is the part number that is stamped into them correct?

Anyway, good call on trying to get the correct pats and not "making them fit." Those things would not have lasted long if they were all stretched like that.

[jwetering]

Yes, the part number stamped on the bottom was correct and so were the BMW and Freudenberg OEM manufacturer logos and so also was the label on the packaging. The Freudenberg logo also appears on a set of e34 mounts I inspected along the way. These were the correct OEM mounts no question about it.

So here's the deal.


I put out a call on my local chat group to ask if I could have a look at a bone stock m42 e30 to inspect their motor mounts. I had an offer from a member who said he had just installed brand new mounts which he had bought from a dealership and that they had bolted right up no problem.

I called up my local dealership and ordered a set of motor mounts. They arrived the next day and when I went to collect them they looked *exactly* like the mounts I had ordered earlier. Top pin was offset to the outboard. I didn't take then home and I didn't take a picture - they remained bagged at the dealership.




So then I asked the guy who had just successfully installed the mounts if he had his old ones I could inspect and he said no - they had been discarded.

I asked if I could crawl underneath his car to see first hand wtf was going on he said sure - c'mon over.

When I arrived the car was already jacked up and on four jackstands because he was adjusting his trans mounts. He had installed poly mounts and the car was buzzing hard. (unrelated - but lesson that trans mounts are the ones that transmit most of the NVH - motor mounts less so).

So i crawl underneath to look at the passenger side which is most clearly visible and I see this:



The top of his mount was skewed hard over and the bottom of the mount was not seated on the perch. His OEM mounts were dead wrong also but this was not visible from up top so he thought they were right.



So *then* I ask my original parts guy to bring in as many mounts as he could from his source. He brought in four mounts - two were OEM but two were aftermarket made by MTC. The OEM mounts both had their top pins offset outboard - so still wrong - but on the MTC mounts the top pins were offset inboard.

I bought the MTC mounts and this is one of them in profile:



See the top pins is offset inboard.

I installed them and of course the bolted right up without issue.

This is the passenger side installed, no skewing at the top and seated perfectly on the perch. Drivers side is also seated perfectly.



So long story short is that BMW has a major issue with e42 motor mounts made by Freudenberg. I would have preferred to use OEM instead of an aftermarket - but BMW has let me down big time.

[jwetering]

Update:

The guy who's car and mounts I inspected and found to be wrong compiled my photos and sent an email to BMW Canada (we are in the Vancouver BC area). They said they were aware of the issue and were trying to resolve it.

Nice to see they aren't trying to hide anything anyway.

[bmwman91]

Wow, that is crazy. Someone somewhere along the line read a drawing wrong and set up their tooling backwards. This is of interest to me because I have a pair of OEM M42 mounts on order as well for when I reinstall my engine. I guess that I will either need to hope that they are made by someone other than Freudenberg or grind off the tabs. Thanks for the heads up!

[roguetoaster]

Interesting, hope the MTC ones hold up. Also, removing the tab seems to be okay on solid mounts, but considering the construction of the filled mounts I strongly suspect that much offset or rotation would quickly cause mount failure.

[jwetering]

Plus the tabs aren't the problem - it's the studs up top. After grinding the tabs you would still need to rotate the mount 180 degrees at which point the motor mount would be hanging half off the perch.

Here's a copy of the graphic that was sent to BMW Canada which led them to acknowledge the error. Credit to a local e30 enthusiast called Louie. He's the guy that installed the dealer sourced mounts which don't fit. He's on this forum but I don't know his handle. He may pipe up.

[bmwman91]

Hmm, well I think I will be speaking with the dealer that I am buying the mounts through. The whole order is currently on hold as a couple of odd bits are on order from Germany, so I have time to check with them on this. If the ones that they have are also wrong, then I am not sure what I want to do. The non-OEM ones are sort of notorious for crapping out! I have sent a message to the part vendor asking them to verify the feature positions. I have no idea if being in the US means that there is any difference in who manufactures the parts for the dealer, but I doubt it since these cars are old and honestly, I'd bet there is only one company making this part anymore!

I used to run M30 motor mounts, which worked fine but transmitted a lot of vibration and noise. God help me, I don't want to go back to those! Does anyone know of aftermarket poly ones which are softer than the M30 rubber mounts? Obviously those won't be as soft as the stock hydraulic ones, but at least it would be an option if BMW does not fix this (and I am not sure if they really have a reason to care about this since E30's with the M42 made up ~3% of all E30's which are basically obsolete).

EDIT:
So there are these, as an option. I am not sure how much harder they are than stock, or how they are versus the M30 rubber mounts I ran many years ago (which were sort of awful lol). I've emailed them asking how they might compare.
https://www.garagistic.com/products/...gs-11811137076

[bmwman91]

I received my mounts today and they are manufactured correctly. There is no indication of which company manufactured them, but the BMW dealer sticker on them said that they were made in Romania.

It is hard to tell from the pictures, but it looks like the stamped steel bottoms of yours are shiny silver colored. Mine have the yellow zinc chromate plating on them, if that somehow serves as some sort of indicator.

I bought them from getbmwparts.com which is the online retail arm of BMW of Silver Spring / Tischer.

[TobyB]

Ahhh, BMW 'mobile tradition'

We've been dealing with this with 2002's for some time now. Like, the last 20 years...

BMW subs out manufacture of their older parts, and historically, not always very well.
This seems to confirm that they're still doing it, and not checking their shit before they ship it.
You'd think, as the OE, they'd bother to do a dimensional check of what they've ordered and are selling as their own...


t

[E30SPDFRK]

Just wanted to update this thread, I just ordered a pair of M42 mounts from BMW, and they showed up oriented correctly.

Manufacturer is Freudenberg, manufacture date is 2/16, so I assume they found some old stock from before the defected ones.