964 RS Engine mounts

Hey all, Probably should have started this thread before I bought my 964 RS engine mounts but oh well. Anyone have any feedback on the installation and performance of them? I'm referring to RS mounts not semi solid mounts in general. There are plenty of threads on the Wevo and RSS but not a whole lot on the genuine semi solid RS mounts - assuming they are slightly tricky to install because they are all in pieces. Also for anyone that has installed them did you use your original top mounting bolts and did you add the washers as shown here: Here is the parts breakdown, I noticed the 964 retaining bolts weren't threaded to the top so I assumed i'd need to use my original mounting bolts on top and the bottom. Thanks!

I had the RS mounts on my 4S. You will notice a big difference compared to the soft original mounts. The rear end will feel screwed together. Engine will not flex on its mounts during hard cornering or change of direction. They made a big improvement for track days but can be somewhat harsh on bad roads or over expansion joints. I lived with the compromise. No added vibration to speak of. Also improved shifter feel to an extent.

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Thanks hardback, my engine mounts needs to be replaced they have a very slight sag. Were the RS mounts tricky to install? Did you use the same mounting bolts + the gold washers that come in the kit? ​​​​​​

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I did RS mounts a few months ago and I don't think it took over an hour. I bought the kit from Renn Part and it came with all the hardware so I used new stuff.

Thanks, I guess you used the mounting bolts that came in the kit. I'm not sure if I need to use my original bolts + washers or get new bolts. I ordered the parts I needed so it wasn't really a kit so it doesn't come with the new mounting bolts. Although I've seen that the 996 bolts are threaded all the way up the bolt, whereas the 964/993 bolts are only half threaded. 996: M8 x 40 964/993: M8 x 45

Received the kit yesterday from 5150motorsport. Can anyone confirm the main bolt length they used on a 996? Compared to the spare original mounts I have the bolt looks too short? Or does the engine carrier bracket/engine get lifted higher until it's touching the bottom washer and as such the additional length isn't needed?

I cannot answer your question directly, but I do remember that my mount bolts seemed a lot longer than they needed to be on the stock mounts.

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Thanks I recall seeing that too, just dont want to get halfway through the job and realise i've got the wrong bolts!!

Hey all, Wanted to do this on the weekend but still not confident enough to tackle it. Also i've just noticed the these washers that came in my kit are much thicker, they are 5mm and there are two of them so 100m of washer. They look much thinner in this image posted by SoCal. Any ideas??

I don�t see the issue. A motor mount is a pretty simple device. As long as those bolts are tight and don�t loosen up, I don�t think there�s much to worry about, except not propping/supporting the engine during the process. If you start with the right side and make sure you�re able to replace that one, you will know that the left side will work as well. The left is harder to get to with the secondary air pump that needs to be moved out of the way.

Thanks, the few concerns I have are: - are the 964/993 RS bolts long enough - when I remove the old mounts will I have to raise the engine so the carrier meets the bottom of the new mount? Bought a brand new 3 ton 70mm low profile jack and planning on also using some jack stands just in case too. Just unsure of what happens movement wise when I undo the 18mm bolt guessing/theoretically nothing because the weight of the engine is supported by the jack, right?

With the car on jackstands on the rear jack points (supporting the body) and a jack under the engine (supporting the rear of the transaxle), you can remove the motor mounts and replace them one at a time without any concern.

Thanks, wasn't planning on using the jackstands for the body is that necessary?

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Here�s what I did: No Jack standards. I placed a wood block between the jack and engine. I then started to jack up the engine - watching it rise maybe 2� or so, taking note to make sure nothing at the top of the engine hits the rear deck ceiling. I figured my mounts were sagging, and if I lifted the engine weight (about 400lbs), then the engine wouldn�t fall. The bolts that held my engine in place were very long - maybe 4� past the nut. So you will see right away if you aren�t supporting the engine.

I did what Murphyslaw says. I also needed a large breaker bar to loosen lower nuts. Even after soaking them.

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Theoretically, if you lifted the engine up a bit, nothing would happen when you start to loosen the nut.

I think u r stressing a little too much over a pretty simple repair. Sometimes u just have to suck it up and start.

It sounds daunting, but is actually super easy. It was much harder when I had to mounts on other vehicles. This one is easy.

If you are only supporting the rear of the car with a jack under the engine, it may work, but you have that entire mass being supported by two tiny bolts at the rear of the car once you remove one mount (and yes, two bolts at the front near the nose of the transmission). I�m sure it has worked fine for a lot of folks, but why not take the extra 10 minutes and put some jack stands under the car?

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Yup you're right! I think i'm looking so far into it because they are the RS mounts too! Also because I need a second set of hands to hold the top 19mm nut. On the 18mm nuts i'm planning on using my air wrench with a deep 18mm then doing them back up with my 1/2 drive torque wrench. I'll just dive in tomorrow afternoon! Keep you all posted.

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Might do that for some added security

Send me a ticket, i would be happy to fly in and help

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Haha happily! Weather is getting warmer here too. Winter is over and we're into spring!

Hey all, sorry to go on and on about this but does anyone know the main bolt length that should be used for the 996?? I have a feeling that the gold main bolts I have: hexagon-head bolt m 12x1,5x105 will be too short and are actually for a 964/993 I've read that 900 082 118 01 which is M12 x 1.5 x 125 is a better fit - it's also silver which is the same colour bolt in the Suncoast image and on SoCal's car?? Really isn't much info on this the longer bolts are only $9 from the dealership so i've ordered them but it would be nice to know before hand.

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I received this email after I placed my order so it looks like you are correct. Unfortunately, there is no way I can get you a measurement since they're already on the car. You could try shooting an email to Rennpart though.

Thanks SoCal! I ended up buying them from the dealership here they are correct for a 996. Part number is: 90008211801 Would you be able to please let me know how much thread you have on the bottom of the main bolt? I have two or three threads and I dont feel its enough or at least it doesnt sit well with me... Thinking about removing the bottom 5mm washer do the bolt has a bit more length. Thoughts?

It�s really not a big deal. The only reason to use jack stands is to give yourself a little more room to work. I actually backed my car up on ramps which gave me plenty of space. Put a jack under a solid spot on the engine and lift slightly (just to take the weight off the main nuts. You may need to soak them with a little pb�s). Once you break the main nuts loose, it�s about a 15 minute job. **Because my main nuts were tough to break loose the whole job took about an hour... good luck.

2 or 3 threads is plenty. What sticks through the nut has no effect on strenght or function. If the bolt is tight it wont back off so i think u r done, congrates.

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Thanks all, thats definitely more thread that whats on mine errr if its not too much trouble would I be able to please see whats on the top of that bolt? Going to try and source longer bolts as i'd prefer that much thread

As long as you have any thread (even 1) past the bottom of the bolt, you're fine... That part of the bolt isn't doing anything to hold the engine. With the full weight of the engine and the torque spec of 63 ftlbs (IIRC) there's little to no chance of those nuts backing off... Just make sure you use Grade 8 or better bolts...

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My first post in this thread has some top pics.

Seen these on eBay , are these the ones? Says replaces stock hydrolastic mounts, I know they are not genuine but can you make a ***** of a metal plate with a rubber block inserted in it?

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They are the non genuine URO mounts - basically the same without the 964 part number. I'd still buy all the other bits though. Thanks everyone for their help! So wrap this up I've only briefly driven the car so far I do like it although the mounts do introduce some vibration - I feel it mostly at idle when stopped. Driving the NHV feels almost the same. Car does feel much tighter but I could see how this mod wouldn't be for everyone. I'm a fan though! I'm sourcing slightly longer bolts for my own piece of mind ​​​​​​ ​​​​​​

Looks like you are across the globe, so you may have different needs, but I would say for anyone stateside, working with Aaron from Rennpart is great, and he will get you all the right bits you need, rather than you having to sort it all out yourself. I've had great experiences with him and his business.

Out of curiosity, how much thread is there below the bolt on the standard mounts? I've found M12x1.5x130 bolts with a Porsche part number that I'm waiting on from Germany. Hopefully they are 10.9 grade like the current ones I have.

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Found the answer to my own question so if these M12 bolts are 10.9 grade they will be the perfect length being M12x1.5x130 because they will provide an extra 5mm. Here is the standard mount thread​​​​​:

Update on this, so now have a decision to make - the bolts I ordered are 130 in length however they are 8.8 grade rather than the 10.9 of the current shorter ones. Thoughts? I can try and get M12x1.5x140 10.9 or just use the 8.8 grade and move on??

You are massively overthinking they will be fine.

Dan, I�m almost sure now that you�re pulling our leg! That was a good one, but you gotta keep it going. I�ll nibble at this a little more... Grade 8.8 vs. 10.9 shows that 10.9 is about 50% stronger than 8.8 when looking at tensile and yield strength. The yield strength for 8.8 is still high - 92,800 psi - and if you think about the loads being exposed to this bolt, I cannot see how the bolt is that critical. All of the weight from the engine is sitting on the shaft for the mount, not the bolts holding the mount to the car. So at rest, the bolt does nothing or very little. The bolt is likely subject to vibrations and forces during cornering and deceleration, shifting harshly (which isn�t good for any component - so don�t do that), etc. The bolt, when tight, may not even be doing that much as the majority of the forces should be contained within the mount itself. That�s actually the purpose of the mount - contain the vibrations and support the engine. However, since I think you are pulling our leg, the best way to ensure the bolts you have selected are up to the task and will provide continued performance over the long-haul, I recommend that have the bolts magnafluxed to check for any stress fractures before using them. Secondly, bake the bolts at 400 degress for 8 hours. This will reduce possible internal forces created during manufacturing. Third, every six months, visually inspect the bolts on the mounts to make sure they haven�t loosened up. I would also take the time to apply a torque wrench to these bolts to make sure they are still tight. Finally, replace the bolts every 3 years to prevent DBSCAMSO (Density-Based Spatial Contamination of Anion Metallic Sensitivity Overload). https://www.boltdepot.com/fastener-i...ade-chart.aspx

Haha thanks gents!

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Hey all, sorry to go on and on and on about this, one last question I promise! Is there any concern that the mounts look slightly angled forward? I.e. the top gold washer looks to be angled towards the front of the car creating a gap at the back of the washer? Also SoCal your right mount doesn't look quite flush to the body? Might need to be re-seated?

The bolt is shifted slightly forward on mine

Think I've answered my own question... The mount bold seems unaligned because the carrier expects the square locating part of the bolt to keep it in place. The 964 RS mounts don't have that it's just the bolt. So with that the bolt becomes unaligned as there is play and nothing to keep it dead straight. Thoughts? I. E. If you're mega pedantic buy Wevo or RSS mounts ha!

It may have moved because of type of lock nut. It should not move. Try Nord Lock. My OLD shop screwed up my engine install with wrong bolts but finally put some correct longer bolts in & Nord Lock. Not done correctly the first time. Like many other issues. ugh.

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Your coolant level is low...very low.

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Did notice that too, I'll top it up As for the movement, the bolt hasn't moved. I still think it's because there is no locating square nut holding it in place in the carrier.

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Thanks Gofishracing, the type of bolt I used actually has those indentations? Around the bottom of the head and its a 10.9 grade with extra thread on the bottom. I actually replaced the bolts haha. Seems ok but I do think because of the lack of the 150x150 square locating section that the RS mounts dont have the bolts can skew slightly. Not sure if I need to have another go at aligning them?

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You could use a square nut or a couple of square washers on the bottom of the mount. I think it would be tough to find a M12 nut with a 1.5 thread pitch though.

It would, also the bolts I have arent fully threaded too eek, wouldnt be such a bad idea though. I do have some longer M12 x 1.5 10.9 grade fully threaded bolts. The requirements are difficult to meet because they need to be 150x150 in size M12 1.5 pitch Have you had any issues with your mounts being slightly off centre? Or is this just how they are?? TBH to anyone thinking about the 964RS mounts you're better off with the VEVO or RSS for simplicity

holy crap guys, put the mental masturbators away and just go drive your cars. its FINE

If Hagerty or Jalopnik gets a hold of this "off center engine mount" info the 996 value will plummet. Damn, I just purchased mine before Mount Gate.

Sometimes the standard engine mounts are better. I did regular mounts, they installed perfectly, and my car handles great.

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I could not agree more. Did the same thing, perfect fit, and no messing around.

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Lol, I consider my motor mount replacement complete and have no intention of going back in. I was just offering suggestions to the OP who seems concerned.

Readjusted and got the mounts to be slightly more centred but without the square retaining nut the bolt goes where it wants to Letting this go! Thanks all

The concave washers are upside down in this picture. The edges should turn up from the mounts, not down into the mounts.

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????

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Thats definitely incorrect and if you have installed a set like that you should change them immediately...

With the choice of which way to put the gold cup washers, I understand there is no wrong way, cups facing away from the rubber for more compliance, cups "cuddling" the rubber for more control. Even both cups facing up, or both cups facing down, there is a range of "tunability" to the setup. The other point is, there is a Porsche technical bulletin detailing a change to the "flat" washers. (updated washer 12.7 x 45.5 x 5 999 025 091 02) These have been upgraded to a much thicker and larger outside diameter for better support of the cup wsher. Probably to combat permanent bending distortion of the gold cup washers from a high G event, such as a canyon sized road dip, or a rally worthy jump. But seriously, who jumps their Porsche these days?

Realised that I never updated the thread... In part due to fear of repression :-p Anyway ended up finded some longer bolts that were 10.9 spec - actually from a cayenne 9PA was a suspension bolt. I have the part number somewhere - only catch is they come with a washer you need to carefully cut off. ​​​​​​

First post on here. I thought I could help clear a few things up for anyone reading this. On a 996 you must use the original mount carrier as in the picture. You must fit the seats with the concave side facing the mount as there is no range of "tunability" to the setup. This is the correct order. Please see the attached technical bulletin which also applies to a 996. I hope this now makes it easy for people reading this thread to understand what is needed.

Quite a few months on this setup and no complaints. About to install black transmission mount inserts so ill see how they go with these.

Hi, Hopefully I�m attaching to the right thread here......there were many My question, I did the 964 RS mount upgrade a few months back, I am not driving the car much but took it out on a 100 mile run last Friday. I swear the NVH noise was higher than when I installed the mounts back aways. Looked at the mounts today and it appears the wide concave washer is now riding on the motor mount body, i.e. the mount has settled or is sagging. Should it be riding this low as to touch the mount body, I took a very fine pic to see if there was any gap between the concave washer and the mount body. I could not insert the pic in the front section of the mount and only be 1/16� or so at the rear... Wonder if anyone is experiencing this, these were not the OE RS mounts, I got the URO mount from Pelican.

That doesn't look quite right there should also be a washer under the bolt head.

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If the concave washer is indeed contacting the surface of the mount, then yes, I think that's an issue. It would also explain the increase in NVH. With my OEM mounts, you can see that there is rubber showing between the washer and mount.

There are updated washers from Porsche Fitted to my 997.2 C2S. Up spec washer. Thicker and larger diameter.

Thanks for the feedback all, yes these are the updated washers that Porsche recommended for the X73 retrofit. I caught the service bulletin they put out and ordered the newer washers before installing, not sure anyone has seen some of the photos shared by others with the concave washer heavily distorted with the smaller washers/spacers, its a problem....not sure why the folks selling these retro kits have not updated their offering... Looks like my mounts are shot after 8 months.....maybe 500 miles of driving......guessing just poor quality of the URO mounts, will call Pelican Parts and then see if I can order the OE 993 RS mounts BTW, lesson learned a second time....2007 E350, my mechanic installed URO mounts, had it back to him in 2 months because the mounts collapsed...he told me last time he’s installing non-Oe mounts....he has bitten multiple times on this

Sorry was on my phone and it appeared like there was no washer under the bolt head. I actually used 10.9 grade bolts from a Cayenne that had a flanged bolt head.

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Are you sure there has been a supersession? Hasn't changed since 2009 and the part number usually gets updated (my PET2 is up to date as well):

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Unfortunately this is pretty much par for the course with everything sold by URO. Kudos to you for reporting back! Most Porsche owners keep it private when their aftermarket part purchases don't pan out.

Here is a link to the bulletin that I came across if this helps anyone https://rennlist.com/forums/attachme...rvice-memo.pdf

Wanted to report back on this, still baffled.......yes I should buy the Porsche OE mounts but Pelican Parts offered to replace the URO�s so though I would give it another try (bad batch or something), only takes about an hour to install. I took a photo of the mount coming out side by side with the new URO mount, for sure there was some sagging, installed the new mounts and much improved NVH and also shifting The bad part, went out later in the afternoon, the concave washer appears it�s close, very close again to the mount body. I�m guessing its just days till it ends up touching again..... Has anyone else experienced this, I know there are quite a few vendors kit packaging these with hardware with URO mounts. I know it�s not correct but maybe flip the Concave washer around......? Something just doesn�t seem right.....would a worn trans mount cause some extra pull on the engine mounts maybe? The bolts do look like they end up with a slight angle after settling..

Honestly I wouldn't trust the URO mounts just buy the OEM - this is engine suspension were talking about here. Not time to save costs or if you're concerned ditch them and go new original.

Did you get new OEM mounts in, and did that sorted the problem? I�m looking at installing RS engine mounts in my 996 GT3 so this is interesting. I was thinking if it could be down to the watercooled engines are a bit heavier compared to the aircooled engine that the RS mounts was originally designed for and thus settles a little bit more? My previous experience is that rubber engine mounts take a decent seat after installation. For example I have installed brand new OEM rubber engine mounts in a previous cars, most noticeable was in my BMW M3, the new was +5mm from the old OEM they were replacing. No issues at all with the old, just precaution since the engine was out anyway. I took measures to reduce the height of the engine since I thought the engine would sit +5mm. My bad, since the engine over a short period of driving settled on the new OEM rubber engine mounts and ended up touching the front subframe.. Nothing to do but raise the engine back with washers those 5mm and all good. What i'm saying is that OEM rubber mounts will take an initial seat, quite noticeable. Can't say that it is the same with the RS, but they are also rubber mounts with similar volume of rubber in them as the M3 mounts. Just a note. Is it confirmed that the �RO are produced at another factory different from the OEM? Thinking since they are so identical except the part nr, it is not far fetched that the factory are selling non branded versions on the side? Not uncommon at least. Anyway I was looking at the �RO option, but perhaps just bite the bullet and buy OEM.. /Tomas

Any issues with these mounts? URO mounts any good or am I barking up the wrong tree.

I'd go genuine - think there were reports of issues with the URO mounts