Engine Mounts 996 - which ones?

[Paynewright]

I think my 996 3.6 C2 manual is in need of some new engine mounts as the engine seems to jolt a bit during gear changes when pressing on (could be my dodgy clutch foot!!). They also look quite saggy.

I've done quite a bit of googling on the subject and there seems to be a lot of interchange-ability between different generations / models, along with a raft of aftermarket semi-solid mounts. I'm not averse to the benefits of firming up engine location providing extra noise transmission to the cabin is bearable and they don't cause any consequential damage e.g. stress fractures to engine cradle plate. No track work planned.

Options I've shortlisted to replace with:-

1) Original spec standard.
2) 993 C4 mounts - I've read less liquid & stiffer fore / aft movement
3) 993 RS mounts - metalastic bush plus some bolts / washers to fit
4) RSS / 9products aftermarket semi solid mounts


What have you fitted and what are the positives / negatives?

Cheers

Ian

[Jefferson Steelflex]

The 993 RS mounts get good reviews, but they are not a specific fit on the 996 as they don't have the square mounting nut. However, lots have done them and provided you get the right longer bolts and all of the washers should do a good job.

The aftermarket semi-solids are meant to be a level up. I have the Rennsport ones (with the softest of the 3 bushing options they come with) and they have been great. There is noticeable NVH change, specifically at idle and pull away in 1st but they have changed the dynamic of the car. Most importantly, they have transformed the gear shift to where you would expect it to be - a lot of owners seem to accept a notchy and stiff gear shift, but from my experience these are a symptom of worn mounts and the Rennsport ones I fitted a while back have removed this.

There's not a bad option, the 993 RS mounts work out a bit cheaper (very cheap if you go aftermarket).

[hermes]

I have these in my 997

http://www.function-first.com/products/engine-tran...

As it's used for daily driving I didn't want to end up with something too harsh. Very happy with them.

[jonindorset]

I had the RSS semi-solid mounts fitted, purchased from Design911 with the various discounts. There is a marked improvement in the stability of the car, no new vibrations, noise or harshness and they are a thing of beauty!

Not the cheapest option but very good.

[EGTE]

993RS mounts do increase NVH in the car a little, but I believe they do settle down with time.

Big threads on these on 911UK.com.

[Filibuster]

Last year I opened a thread about this topic myself.
And found this other thread that was very helpful. mmcd87 used 9products semi solid ones.

I haven't bought a set for myself yet. I'm quite intrigued by the 993 C4 ones. I didn't know that!!

[PGNSagaris]

I fitted RSS semi solid engine mounts to my previous 996 and have them on my current one too. Made a big difference - car felt tighter straight away

[JS1500]

Coincidentally I just started this very same thread on 911uk yesterday.
I decided to go with this aftermarket 964/993 RS kit...

http://type911shop.co.uk/epages/de867ca1-377e-432e...

[Paynewright]

Thanks for the replies.

The other option I’d considered but didnt mention was filling the standard or C4 mounts with sikaflex PU adhesive which one vendor seems to be doing also.

Re the square shaft on the 996 - I think this is to do with the design of the fluid filled rubber bit - if the stud wasnt fixed in some way it could twist up the rubber on tightening and unscrew the stud on loosening. The square section stops either happening and with a through bolt its not needed.

I’m erring towards the 993 RS option having read a few more posts on 911uk.

Cheers

Ian

[AlasdairB10]

I talked it through with my indy mechanic and he recommended the rss semi solid mounts. He had worked for some of the big indy garages and seemed to know the older cars really well. I was interested in the RS mounts but his opinion was that the RS mounts werent that much of an improvement over standard. I went with the RSS street mounts and a powerflex gearbox mount. They've really improved things. Bit more nvh but its reducing over time. Engine and gearbox feel much more connected and the car picks up quicker. Im pleased I went with these ones.

[edc]

hermes said:

I have these in my 997

http://www.function-first.com/products/engine-tran...

As it's used for daily driving I didn't want to end up with something too harsh. Very happy with them.

These are the same as gearbox mounts on a 986 Boxster. You can do the same thing yourself with some poly and get the same result for £100's less.

[Paynewright]

Decision made...

Aftermarket 993 RS mounts from Heritage Porsche

Bolts (125mm), cup washers and lock nuts from Porsche Leicester

5mm thick M12 washers eBay £3.97 delivered Vs £38.02 from OPC (Originals 34mm dia and closest ebay ones 38mm, as they sit on top of the cup washer, 2mm extra either side wont make any difference)

The mount to chassis bolts look fine so will re-use.


All in, £158. Await delivery and will hopefully fit next week.

Ian

[m33ufo]

Rennline Tuneable on my 996.2 GT3. Three choices of inserts - road, track or race. Similar to the RSS option but more versatile.

[CocoUK]

Paynewright said:

All in, £158. Await delivery and will hopefully fit next week.

Ian, have you had an opportunity to fit?
Any issues? Pleased with the result?

I'm in need of something similar.

[Paynewright]

Fitted them on Monday and been out for a spin.

I've read all the reviews etc of this (and other semi solid mount) 'must do' updrade and treated the mega positive reviews with some scepticism. However, I've got to say the driving experience is totally transformed - car is much nicer and more settled on the road and gear change sweeter too. I've not noticed any significant change in NVH

All I can put it down to is the sloppy old engine mounts allowing the engine to go up and down when you hit a bump or change gear which unsettles the chassis.


All in all very pleased. There are a few of observations / comments:-

- I needed a deep 18mm socket and breaker bar to get the old ones undone. The nuts were corroded and ended up unscrewing the stud out of the old mount.

- I'd seen advice to use a 125mm length bolt on the 996, however, I think I will change to a 130/135 (if available from Porsche) as there is only about 5mm of thread protruding out of the nut. I think a bit more surplus thread would give warning should they start coming undone. Not likely with locknuts but extra peace of mind.

- Ensure you support the engine properly - I'd say jack it up a bit with a block of wood under the sump to spread the load. When the bolt comes out it effectively takes the weight of the engine off the car on the side you're doing, so the suspension lifts up. You could put on stands to stop this happening.

Regards

Ian

Edited by Paynewright on Wednesday 2nd May 12:46

[CocoUK]

Great reply, very much appreciated and all very positive - actually looking forward to it!

Cheers

[Paynewright]

Porsche Part Numbers (originally taken from Jackals website - 993RS engine mount article, with superseded numbers)

cup washers / seat (x4) 901 305 311 00
125mm Bolt (x2) 900 082 118 01 (supersedes 900 082 118 09)
Locknut (x2) 999 084 215 01 (supersedes 999 084 215 09)

That lot came to £33.74

5mm thick, 12.4mm hole 34mm dia washers (x4) 999 025 074 02 - I sourced from ebay

Ian

[was8v]

Don't forget the gearbox mount too!