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Discussion Starter #1
I brought my car into a shop to get the motor and trans mounts replaced because I was getting a clunk when I was engaging gears and lifting off the clutch. I had no vibration at all with the worn mounts.

When I picked up the car, I have heavy vibration just above idle to about 1k RPM (noticeably when trying to move from standstill), and then anything above 3k+ RPM. I brought my car back to the shop and they said the new mounts would be stiffer than the worn mounts that were replaced (both OEM). They said I should drive around for about a week and the mounts should loosen a bit from new and the vibration should die down. However it seemed like they weren't used to it having this much vibration from a replacement.

Does anyone have any experience with this? Could they have messed something up or does having it soften after install have any merit to it? They actually pressed the bushing out of the motor mount, instead of replacing the whole motor mount assembly. Could this have been pressed in wrong to cause this?
 

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I don't believe the "wait awhile it'll loosen up" story. If that were true then brand new ones on the dealer lot would have the vibration, and they obviously don't.

The motor mount insert is not symmetrical...I wonder if they put it in the wrong orientation when they pressed it in. Or perhaps some other installation error. In any case it's not right.
 

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Yeah, I replaced all three mounts and didn't have any increase in vibration. I agree they likely did something wrong.

It's weird that they pressed out the bushing, the mount I got came as an assembly. It's entirely possible they used some off-the-shelf bushing that's a lot stiffer than the OEM one, that would cause the problem.

The other thing that can happen is if they used two 911 motor mounts in place of the 987 transmission mounts. This is what I did when I did my car. It works fine, and it's cheaper because you can just buy the rubber/metal piece (the round piece on the right) and screw them into the 987 metal supports already on the car (the arm on the left.) When I did the job I could only find the 987 piece available as the whole assembly and it cost a lot more.

The trick when doing this is that the threaded shaft at the bottom of the round piece (where it screws into the arm) is a lot longer on the 911 mount. You need to cut about 1-2" off of it, or I believe it will hit things and cause vibration. You can probably check if this is the problem pretty easy: look under the car with a flashlight and find the mounts on each side of the transmission. If it looks like the one below this isn't your problem. If the shaft below the round piece extends down significantly below the nut, then they used the 911 piece and it may be hitting something.

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Discussion Starter #4 (Edited)
Yeah, I replaced all three mounts and didn't have any increase in vibration. I agree they likely did something wrong.

It's weird that they pressed out the bushing, the mount I got came as an assembly. It's entirely possible they used some off-the-shelf bushing that's a lot stiffer than the OEM one, that would cause the problem.

The other thing that can happen is if they used two 911 motor mounts in place of the 987 transmission mounts. This is what I did when I did my car. It works fine, and it's cheaper because you can just buy the rubber/metal piece (the round piece on the right) and screw them into the 987 metal supports already on the car (the arm on the left.) When I did the job I could only find the 987 piece available as the whole assembly and it cost a lot more.

The trick when doing this is that the threaded shaft at the bottom of the round piece (where it screws into the arm) is a lot longer on the 911 mount. You need to cut about 1-2" off of it, or I believe it will hit things and cause vibration. You can probably check if this is the problem pretty easy: look under the car with a flashlight and find the mounts on each side of the transmission. If it looks like the one below this isn't your problem. If the shaft below the round piece extends down significantly below the nut, then they used the 911 piece and it may be hitting something.
I read somewhere that you can press out the bushing and I bought this bushing for the shop to replace. HERE. Maybe it has something to do with the orientation that they pushed it out at.

I did actually buy the 911 mount as well. I didn't realize that you had to cut the threaded shaft. Let me take a look under the car and see.
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Why would you buy a 911 tranny mount? Its different than a 987 tranny mount. Cost? Engines are reverested! Different application.
 
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Why would you buy a 911 tranny mount? Its different than a 987 tranny mount. Cost? Engines are reverested! Different application.
The actual rubber/metal mount part is the same. Back when I did the job you could save a bunch of money by just buying the 993/996 mount and not the entire 987 assembly, though looking at current prices things appear to be more equal now.

I did it and it worked perfectly fine with some simple modification to the shaft length. No issues for me with the 911 parts after 2.5 years.
 

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Discussion Starter #7
This was the transmission mount I bought. The shop reused the bracket thing that attaches to the mount. However mine seemed short and I don't know if they actually had to cut it. It may have just fit without cutting.

So it sounds like they may have installed the engine mount bushing backwards. I got confused looking at the parts catalog diagram vs the part itself (bushing pressed into full assembly). Guess there was a bushing redesign, and the point of the egg shaped metal faces in different directions based off the style of the bushing. I'm going to have the shop take a look at it after this weekend.

Here are pictures of the different bushing styles and how they should orient. Thought this would be good info in case anyone looks around with this same issue.
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Okay, looks like you got the 986/987 trans mounts so those are unlikely to be your problem.
 

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So, you inadvertently bought a stiffer engine mount. I used a Function First insert that goes into the holes in the OEM mount to stiffen up the engine mount. Even with a new OEM mount and this Function First yellow insert, (not the black one) and new yellow Function First transmission mounts, the NVH is just a little more than stock at startup and at around 2000 rpm. To me its worth the extra NVH to secure the motor and transaxle. I used a Liqui Moly fuel system/injector cleaner to smooth out my startup for about a month. This seemed to work. I either just got used to the NVH on startup or the insert and OEM motor mount just relaxed a touch.



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The feature to look at to determine the proper orientation is the rubber voids. I just helped my son do his a few weeks ago and saw exactly what is shown above in this thread.
The critical feature to look at to determine orientation is the rubber voids.

I can see where a mechanic might have confused the orientation. The metal shape shows the rounded end down in the original. The new parts has 2 rounded ends.

It would be worth asking your mechanic if they are certain it is in the correct orientation. It is also possible a bolt is loose. The mounts will not loosen up in when driven for a few weeks. The rubber is quite stable.

FYI: For those with a 987.2 The motor mount cheaper press in part for the 987.2 is not listed as available ; you must buy the whole bracket. The revised part for the 986/987.1 appears identical and should fit fine without replacing the entire expensive bracket.
 

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Discussion Starter #11
So I finally got resolution from the shop. They attempted to replace the whole bracket but it was still producing vibration. It turned out that the original rubber stops on the sides of the bushing were causing the problem. The original stops on the car were 4mm thick rubber, but the replacement part that fixed everything was way thicker, and composed of a rubber and foam. They couldn't make sense of why the original stops wouldn't work, because the shape of the bushing was the same from before and after the press. Anyways, all good to go now!
 

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Interesting read. I know this issue is resolved, just wanted to ad some info I found regarding my 06 Boxster S Engine Mount.
I pulled the front motor mount as I have a lot of miles and wanted to check if mount was torn or cracking (it was not) while I had it out I removed the two black 4 mil stops and replaced with the "Function First" Orange inserts. After testing I did not like the NVH so removed them but decided to retry them with 1 change . I cut the insert section of each insert that recesses into the stock mount leaving just the outer flange stop (flat section) using a long bladed sharp knife, basically making a replacement stop if u will instead of the black 4 mil stock units. There thicker than stock almost double ,Its worked perfect, less vibes but more rigid than the stock set-up and it may help the stock mount last a lil longer. I did note that Porsche had updated there
stops on newer cars, basically a running change ,u get the newer style stops (slightly thicker) with rubber one side and foam material on the other side of each stop. Not sure which side goes in or out ,it may make a difference. Regardless
the Orange "Function First" inserts that I modified to use as a replacement stop are probably even thicker than the New revised Porsche stops. I have not seen one to measure yet. A change Porsche decided to make and I may have just got lucky in doing something similar . If your not satisfied with the Function First inserts try modifying them, it may be exactly want your looking for.
I think the function first inserted section almost totally eliminated movement and the mount became almost rigid.There needs to be some movement or the vibe will be more than most can stand.I dont track my car so smoothness is more important to me.
 

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FYI, I think the rubber inserts or mounts that u purchased from the 911 (tranny) and engine mount insert my have
harder rubber than stock.Regardless the extra thickness of the engine mount stops must have made the difference.
That just reinforces my decision to add slightly thicker stops in the form of rubber rather than the Porsche runner/foam units. Essentially creating the same outcome.
 

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FYI: For those with a 987.2 The motor mount cheaper press in part for the 987.2 is not listed as available ; you must buy the whole bracket. The revised part for the 986/987.1 appears identical and should fit fine without replacing the entire expensive bracket.
Hey there,

Thanks for the input here. Just to clarify, are you suggesting that you can use the 987.1 bushing in the 987.2 bracket? I've not found anywhere else suggesting that you can replace just the bushing, but find that hard to believe and would love to find a simpler solution.
 

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See C.C. photos below.

Yes. The 986/987 motor mount bushing FCP part# LEM-3470501 , looks like it is also used in the 987.2 motor mount.

I noticed this when I was pressing the part into my son's 986 bracket and my previously replaced 987.2 mount was left on the bench. I took measurements and it looked identical; visually the rubber structure was identical; the rubber hardness also appeared identical including the molding marks.

I wish I knew this before I spent $ on the entire 987.2 mount....
 
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Very interesting--thanks for the info. I already have a new mount on hand, but have ordered the bushing as well based on your info. I will compare the two when the bushing comes in and share my findings here.
 

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Hi all,

I haven't gotten around to a thorough comparison, but I can definitively state that the bolt hole patterns through the core of the bushing are different. Looking at the two separately it's hard to discern the difference, but when you look at them side by side it's more clear. I'll be returning the bushing and installing the full mount.

That being said I don't see why the .2 bushing can't be sold separately like the .1...
 

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Hi all,

I haven't gotten around to a thorough comparison, but I can definitively state that the bolt hole patterns through the core of the bushing are different. Looking at the two separately it's hard to discern the difference, but when you look at them side by side it's more clear. I'll be returning the bushing and installing the full mount.

That being said I don't see why the .2 bushing can't be sold separately like the .1...
Post a pic of each as your observation did not match mine. The upgraded 986 replacement bushing was identical to the one in my original 987.2 mount. Most important, the bolt hole was in the same place.
 

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Post a pic of each as your observation did not match mine. The upgraded 986 replacement bushing was identical to the one in my original 987.2 mount. Most important, the bolt hole was in the same place.
Pictures attached/below comparing the OEM 987.2 motor mount assembly with the Lemforder bushing (LEM-3470501 as stated above; crosses with Porsche 987.375.057.02). The outer profile of the core is the same and the shell OD appears to be the same, but the holes through the middle are not (different sizes and locations within the core). Also, the 987.2 bushing is 10mm longer (core and shell are 70mm/90mm vs. 60/80 on the Lemforder part).

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