Engine mounts 997 - Page 4 - 911/Carrera GT - PistonHeads UK

Want to change my engine mounts to sharpen things up but can’t decide RS or OEM type, car 2005 997 at 82K so expect either will be an improvement . What are other owners experiences ?

Standard unless NVH doesn't worry you...

I went OEM at 90k and the difference was huge, don’t regret not going for stiffer at all it’s ideal. It’s amazing how much slop we’re in the originals despite them not having failed, gear change is hugely improved. RS would likely be fine but obviously be aware vibration will increase. Depends on your use case, mine is a daily so wouldn’t want that all the time. I’m yet to meet anyone who has managed to stick with RSS unless it’s a track car.

My car has just hit 40k miles and a 2011, I wonder if replacing with factory new would be noticeable, my car has just had all new KW V3, front / rear arms and bushed where there were any signs of wear, so hopefully a tight chassis

Adrian-9iafn said: My car has just hit 40k miles and a 2011, I wonder if replacing with factory new would be noticeable, my car has just had all new KW V3, front / rear arms and bushed where there were any signs of wear, so hopefully a tight chassis They should still be OK. One simple test is to look at how low your exhaust tips are (Google for more details). The mounts stretch as they age allowing the engine to drop more.

I changed them on my 996 and fitted 993 RS mounts which are metalastic type. The difference was night and day though I didn’t realise how bad they were until the new type were fitted. Basically, the engine was like a big pendulum on undulating roads and it really unsettled the car. When the car was going down into a bump the engine was still going up! The new mounts transformed the handling. There is no noticeable change in NVH. At the time I researched the various options, buying new std mounts and filling the void with PU adhesive was suggested as a way of ‘firming’ them up a bit.

I replaced mine at 81k miles with the OEM items. Could feel zero difference! Was rather dissapointed and would say to save your money. On the other hand, pleased that the original ones were still good. Tbf, there were no signs of deterioration, such as fluid leaks or drooping exhaust tips. Just all the chat about people getting them done goaded me into doing them. That and the fact that is they break you're stranded. So, on age alone decdied to to ahead. Edited by RiccardoG on Monday 16th October 17:06

Thanks for all replies , quite interesting . Got a price from Porsche Nottingham today at £259 each for genuine parts, however as one post said it’s still money wasted if there’s nothing wrong with my current set . May worth taking the left one out and having a look when I have time ?

Paynewright said: I changed them on my 996 and fitted 993 RS mounts which are metalastic type. The difference was night and day though I didn’t realise how bad they were until the new type were fitted. Basically, the engine was like a big pendulum on undulating roads and it really unsettled the car. When the car was going down into a bump the engine was still going up! The new mounts transformed the handling. There is no noticeable change in NVH. 996 C2 at 60k miles. After replacing with OE mounts, I experienced exactly what you describe. Gamechanging. You’re correct in saying the engine is a big, heavy pendulum, but I suspect the old mounts as they stretch and/or lose their damping qualities, and the engine then moves relative to the body at a harmonic frequency that wasn’t intended by the engineers. The result is an unpleasant front to rear pitching motion that becomes more noticeable at speed over undulating, cresting roads. The new mounts fixed the issue which I’d previously attributed to either dampers, or in extremis, a geometry issue. As regards the tailpipes being a gauge of engine mount condition, when the new mounts were fitted, the tailpipes were less than 7mm higher, so in my experience the sag exhibited by the exhaust tailpipes is not an accurate indicator.

Another 996 owner here. I also fitted 993 RS mounts as well, plus a Powerflex gearbox mount. I did however notice some increase NVH in my case. But it's not my daily driver, so I can deal with it.

Slippydiff said: 996 C2 at 60k miles. After replacing with OE mounts, I experienced exactly what you describe. Gamechanging. You’re correct in saying the engine is a big, heavy pendulum, but I suspect the old mounts as they stretch and/or lose their damping qualities, and the engine then moves relative to the body at a harmonic frequency that wasn’t intended by the engineers. The result is an unpleasant front to rear pitching motion that becomes more noticeable at speed over undulating, cresting roads. The new mounts fixed the issue which I’d previously attributed to either dampers, or in extremis, a geometry issue. As regards the tailpipes being a gauge of engine mount condition, when the new mounts were fitted, the tailpipes were less than 7mm higher, so in my experience the sag exhibited by the exhaust tailpipes is not an accurate indicator. But they were lower. If they were not 7mm lower than new then they probably didn't need changing. Not huge I agree, but measurable..

I just bought a pair of these for my 986 but not fitted them yet Cheap yes Basically just a solid rubber bush Shape of the mount is slightly different so not sure fitting is as simple especially on the 986 but thats probably not as relevant on the rear engine cars You can see on the underside they dont have the square section which helps locate or orient them correctly on the 986 - not seen the 996 setup yet https://www.ebay.co.uk/itm/234268687380

ATM said: I just bought a pair of these for my 986 but not fitted them yet Cheap yes Basically just a solid rubber bush Shape of the mount is slightly different so not sure fitting is as simple especially on the 986 but thats probably not as relevant on the rear engine cars You can see on the underside they dont have the square section which helps locate or orient them correctly on the 986 - not seen the 996 setup yet https://www.ebay.co.uk/itm/234268687380 They're the 964/993 RS mounts. I'd say you got a good deal there ... https://www.carnewal.com/products/964/p93114/RS-Mo...

What to measure and how do you see a 7mm drop ? Ive been looking on google, at pictures of very low mileage cars and non the wiser My car looks like this, good or bad !?

Discombobulate said: Slippydiff said: 996 C2 at 60k miles. After replacing with OE mounts, I experienced exactly what you describe. Gamechanging. You’re correct in saying the engine is a big, heavy pendulum, but I suspect the old mounts as they stretch and/or lose their damping qualities, and the engine then moves relative to the body at a harmonic frequency that wasn’t intended by the engineers. The result is an unpleasant front to rear pitching motion that becomes more noticeable at speed over undulating, cresting roads. The new mounts fixed the issue which I’d previously attributed to either dampers, or in extremis, a geometry issue. As regards the tailpipes being a gauge of engine mount condition, when the new mounts were fitted, the tailpipes were less than 7mm higher, so in my experience the sag exhibited by the exhaust tailpipes is not an accurate indicator. But they were lower. If they were not 7mm lower than new then they probably didn't need changing. Not huge I agree, but measurable.. Ok, out of these images, in which image/s have the engine mounts been replaced, and in which image/s are the old mounts still installed ? 1. 2. 3. Here are the tailpipe measurements before the engine mount swap : Before N/S Before O/S And bear in mind that I stated " In my experience the sag exhibited by the exhaust tailpipes is not an accurate indicator "

Slippydiff said: Ok, out of these images, in which image/s have the engine mounts been replaced, and in which image/s are the old mounts still installed ? I'd say images 1 and 2 = pre replacement.

RiccardoG said: I'd say images 1 and 2 = pre replacement. Next. That's you BTW Discomark

I agree ! 1 and 2 pre replacement ?

Wait I thought the back box on 996/997 was mounted to the car and has a flexi connecting it with the pipe coming from the engine? Not like a 986 where the exhaust is all mounted to the engine assembly and moves around as one and in sync. Yes this one is sagging badly.

ATM said: Wait I thought the back box on 996/997 was mounted to the car and has a flexi connecting it with the pipe coming from the engine? Not like a 986 where the exhaust is all mounted to the engine assembly and moves around as one and in sync. Yes this one is sagging badly. No, the the 996 cats are mounted to the rear engine crossmember (the end "tongue" of which can be seen arrowed in red in the image below) which in turn is attached to the engine mounts and they in turn are attached to the bodyshell) The silencers are hung off two brackets which are bolted to the cam covers/cylinder heads, which are in turn connected to the rear engine crossmember, which is attached to the engine mounts, which are attached to the bodyshell ... If those engine mounts sag (and rest assured if someone attached to 250kg of engine/transmission to your ankles and left that weight dangling from them for 22 years, day and night, you're legs might be past their best too ...) all the exhaust comes down with it it.

Slippydiff said: Ok, out of these images, in which image/s have the engine mounts been replaced, and in which image/s are the old mounts still installed ? 1. 2. 3. Here are the tailpipe measurements before the engine mount swap : Before N/S Before O/S And bear in mind that I stated " In my experience the sag exhibited by the exhaust tailpipes is not an accurate indicator " Mine were 35 and 37mm before, and 13 and 14 mm afterwards. 2008 62k mile car But yes, 7mm of sag is small / hard to spot, so it's not a reliable sign.

I have measured mine and the RHS is lower than the left by around 2-3mm

Slippydiff said: No, the the 996 cats are mounted to the rear engine crossmember Damn I knew this Pic from PO showing full engine assembly before it was mounted in the car

Discombobulate said: Mine were 35 and 37mm before, and 13 and 14 mm afterwards. 2008 62k mile car But yes, 7mm of sag is small / hard to spot, so it's not a reliable sign. For the record, pictures 1 and 2 were before and after I’d changed the mounts. Picture 3 (how the tailpipes should sit, but rarely do) was after I’d replaced the tailpipe clamps and fasteners, and adjusted the tailpipes properly...

Ok, the measurements had me out to the garage with a tape measure and seeing mine at 30mm ish I have ordered some OE type Bilstein parts £150 a side with a 20% voucher offer, so £230 delivered . Will take some exhaust tip measurements before and after !! Who knew engine mounts could be so interesting 🤣

Look forward to seeing the results, also curious about what the options are for non Porsche parts priced items and how they might compare

By the way what mileage are we talking about, my car has just hit 40k miles a late 2011 C2

ATM said: I just bought a pair of these for my 986 but not fitted them yet Coming back to this I've found some internet people who claim you can recycle your old tired mounts. You inject them with some fluid which hardens. Like filling them with glue. Then they work again but are stiffer. And it costs peanuts. I might have a bash. We'll see.

Adrian-9iafn said: By the way what mileage are we talking about, my car has just hit 40k miles a late 2011 C2 Mileage irrelevant. My 986 was on 22800 when I got it and the mounts were already shot.

Hi, i have RSS mounts on my 997 C4s & find them excellent with nhv only reasonably noticeable at tickover. The whole driving experience is much better than oem in my opinion.

ATM said: Coming back to this I've found some internet people who claim you can recycle your old tired mounts. You inject them with some fluid which hardens. Like filling them with glue. Then they work again but are stiffer. And it costs peanuts. I might have a bash. We'll see. https://www.function-first.com/products/engine-mount-upgrade-v2?variant=42772272513177

I do think I'll replace them, I have been reading about RSS and have heard of a few others. I dont want to add much harshness if I can though. I have had solid engine mounts before on a few cars and alway ended up taking them off From the reviews I've seen the RSS seem to be the leats intrusive ?

A good review of the function first, looks promising https://rennlist.com/forums/997-forum/1270452-revi...

Another vote for FF and a swap from RSS, getting more interesting ! https://rennlist.com/forums/997-forum/1235279-func...

I think I'm sold on the FF https://rennlist.com/forums/997-forum/1218471-func...

Adrian-9iafn said: I think I'm sold on the FF https://rennlist.com/forums/997-forum/1218471-func... Keep us posted how you get on please

I've ordered a set, will let you know how it goes, fingers crossed I like them

Well, my mounts have arrived, unfortunately I can’t budge the the m12 nuts, have given them a soak and try again tomorrow .

How are you getting on with the mounts ?

Very pleased with myself this evening, after a soak with WD40 and a more manly 1/2” drive breaker bar I managed to get both mounts changed in under 2 hours . Exhaust tips only about 4 mm higher but out for a drive the car certainly feels tighter when accelerating hard up and coming out of cambered islands. Definitely £230 well spent as pretty sure removed mounts were original and looked very tired.

Looks like my FF will be expensive as £330 including postage from the US and now import and taxes of £85, so its a £400+ item !!!

I went for aftermarket RS types - massive improvement and stopped the engine flopping around, which improved the feel in bends. A tiny bit of NVH increase initially but that seemed to bed in and I don’t notice anything now. A vast improvement on my 75k miles car.

Adrian-9iafn said: Looks like my FF will be expensive as £330 including postage from the US and now import and taxes of £85, so its a £400+ item !!! FF just fill OEM mounts with a hard polyurethane in the void. Just buy your own and do it yourself with some poly roof sealant for £10 and a few hours. Not sure on what hardness to use but you're paying a lot for them to do it for you.

I wouldn't bother. Just fit new OE items, as I and plenty of others have found out, the difference with them (even unmodified) should be transformational,

I'll see how they are but I must admit I initially thought they were the same price as std, I am sure they will be better than my original, but how much better or worse than new stock I wont know !

Adrian-9iafn said: I'll see how they are but I must admit I initially thought they were the same price as std, I am sure they will be better than my original, but how much better or worse than new stock I wont know ! That's the thing ^ Lots of great reviews for them on Rennlist, but .... if you've just removed 22 year old 65k mile mounts and fitted brand new OE mounts like I did upon buying my car, any new mounts will feel vastly better, it's a bit like replacing tyres which were years old/well past their best (and down to the legal limit) with new tyres of the same brand and of equal performance. Of course they'll feel absolutely amazing !! So all those saying the FF mounts are a "vast improvement". A vast improvement over what ? 10,12,14 year old 100k mile items ? Well duh, no sh*t Sherlock Or vastly improved over the brand new OE items the previous owner fitted less than 12 months and 4k miles ago ... ??

Interesting the actual mount they modify is a 993 part 993 375 049 08, it's an OEM replacement part not from Porsche, the FF transfers were customer fit

Here's what my OPC supplied for my 2002 996.2 C2 manual coupe .... :

Interesting, well mine will get fitted next week, so I'll see how they feel

ATM said: Mileage irrelevant. My 986 was on 22800 when I got it and the mounts were already shot. Got them off

Okay, one short trip back from the garage and on a short dual carriageway. Actually quite please alread. The car feels tighter and more tied down, the transmission, chassis and car seem more connected, with KW suspension this taughtness feels sportier and 'right'. Idle has some vibration, but not harsh just some low rumble coming in to the chassis Some NVH coming through as you rev and between 3-4,000 but overall not horrible and I understand this will improve The chassis feels, taughter and better connected, early days but in comparison it felt as though the drivetrain was floating separately before and now its connected and that shows through in on off throttle, movement between gear change and pulling away. It feels sportier more GT to the chassis and 'older' 911 in some ways If I keep the toughness and lose a little of the rumble shimmer then it will be very good indeed. If I don't it's still a good trade for a sporty drive. In my car there is no 'harshness' just a feeling of the drivetrain is better connected and the movement that happened before is now controlled by the chassis and structure. The 'old' units do look in good condition and still feel pretty tight

Yes yours do look pretty good, this was my new v old url] |https://thumbsnap.com/dEa8Bi3Y[/url]

ATM said: ATM said: Mileage irrelevant. My 986 was on 22800 when I got it and the mounts were already shot. Got them off I can't really detect any noticeable sag in my old / current mounts now they are removed. So I'm tempted to refit which will give me an opportunity to remove the front mount and inspect.

I took it for a longer run and I found 1. the suspension seems more consistent and better over large bumps, perhaps stopping or reducing the engine pendulum effect has avoided the suspension and engine working against each other on som undulations 2. Definitely feels more tied down and more integrated as a car 3. The gearshift has improved, but not life changiningly 4. Changing direction and weight transition feels more together, it feels more like a newer tighter chassis 5. the sense of some transmission float and chassis being separated has gone (I didnt really know it was there until it went !) 6. The 'price' at the moment is some low frequency resonance, that isn't harsh and feels like the transmission and all that comes with it is simply more connected. I am aware of a more 'gravely' deep transmission resonance at certain times, like revving through 3-4k. It's not horrible or harsh more GT car like

Fitted the upgraded stiffer engine mounts to my 996. Then decided the engine was too high so I had to remove and refit with some spacer washers. These were all included in the box but wasn't sure I needed them. These went in between the mount and the engine to allow it to sit a bit lower. Look how tight the exhaust is here to the bumper. This is without the added spacers. I was concerned throttle body was pressing up onto roof of engine bay. Also fitting had the added problem that these use a big bolt through the mount. Compared to the standard mounts which have a captured bolt so you just have the thread poking down which is solid and can't spin. So when tightening from underneath the top can spin. As a one man mechanic it's not possible to hold both ends so I had to use a spanner wedged in the engine bay for the top side.

This is interesting. Even the GT3RS appears to use the standard mounts. I'm not certain I am just looing at these pics. So it is possible of course that they are different internally but just look exactly the same. https://collectingcars.com/for-sale/2007-porsche-9...

Interesting I think there are a few rubber choices and different part number the normal mount is 997.375.049.08, I think there is .07 version, not sure how many more versions tbh

The GT3's have there own mounts

Adrian-9iafn said: Interesting I think there are a few rubber choices and different part number the normal mount is 997.375.049.08, I think there is .07 version, not sure how many more versions tbh Generally with P part numbers the versions should be interchangeable. And once a part is now on version 2 they will stop making version 1. So generally now real difference. There must be a difference but maybe it could be manufacturing changes or supplier changes.

Not true in this case (and in many) 997 375 049 07 is for a targa or cab 997 375 049 08 is for a coupe 07 will be softer

Here's mine after encountering a particularly large bump on the A2 near Dover which broke the near side engine mount (of course Highways England said there was nothing wrong with the road!)

Another update on the FF engine mounts, now completed about 900 miles, all the resonance has again reduced significantly at 3-4k, If I hold the gear and don't accelerate through there is a dull harmonic you can feel transmitting into the shell, as you go through this rpm, it feels a little more visceral than a stock car and I'm not sure I want it to disappear with more miles, I actually quite like it. It reminds me I have a tight transmission and it feels very connected Overall very happy with the FF mounts

mlsporsche said: Not true in this case (and in many) 997 375 049 07 is for a targa or cab 997 375 049 08 is for a coupe 07 will be softer The final two digits 000-000-000-xx These are known as the “modification number”. For the most part, Porsche produced parts end in a pair of zeros. When you see something other than these two zeros it means there has been a modification to the piece from its original production run. This could me a minor change in the material specification, or even a significant change in the exterior dimensions of the part. Either way, each subsequent modification will receive a new part number with an incrementally higher modification digit. Often, these modifications are completed before the part is even installed on a production-line automobile; however, occasionally there are super sessions that will replace an earlier number. https://www.stuttcars.com/porsche-data/porsche-par...

Sorry, so you are saying the 08 mount is just a newer 07 mount?

ATM said: Adrian-9iafn said: Interesting I think there are a few rubber choices and different part number the normal mount is 997.375.049.08, I think there is .07 version, not sure how many more versions tbh Generally with Porsche part numbers the versions should be interchangeable. And once a part is now on version 2 they will stop making version 1. So generally no real difference - in terms of interchangeability . There must be a difference but maybe it could be manufacturing changes or supplier changes. This I made a few edits to my previous and added bold to highlight these. Going back to the above example the first version should have been 00. Then 01 etc. Now obviously this could have all changed but this is as I understood it. I recently saw reference to this elsewhere and remembered this topic so I came back to it. It is my belief that the last 2 digits are the version number. Nothing else. A new version supersedes the old version. Porsche are now selling version 08 and it can be used in place of all others.

mlsporsche said: The GT3's have there own mounts If the GT3 do have their own mounts and they look the same externally then I'd guess maybe they are stiffer or something like that internally and could be a potential upgrade for the vanilla cars looking to firm things up. They look similar in the pics above but we can only see the top half.

Dangerous and incorrect to think the last 2 digits are just updates, many parts are very different

ATM said: If the GT3 do have their own mounts and they look the same externally then I'd guess maybe they are stiffer or something like that internally and could be a potential upgrade for the vanilla cars looking to firm things up. They look similar in the pics above but we can only see the top half. C2 price is £292 GT3 price is £536 ... That's either weapons grade price gouging, Porsche levels of supertax, or they might just be different ...

The FF mounts now have 1,200 miles on them and the slight resonance at 3.2k and 3.8k is lower again, you can feel a very small amount but it's very nearly gone. As I say I was happy with it by 900 miles and it's less and different, I think it's better without the slight resonance but it really wasn't a problem and I quite liked it from time to time.

Slippydiff said: C2 price is £292 GT3 price is £536 ... That's either weapons grade price gouging, Porsche levels of supertax, or they might just be different ... Yep, I reckon you're right!