Posted: Mon May 15, 2017 8:05 pm Post subject: Rennline heavy duty transmission bushing
For the past few weeks my car has had a nasty vibration at around 3200rpm and lesser vibration at other revs this was not a rattle of trim or anything as you could feel it through the seats, after trying lots of different fixes finally it seems to have been located at the transmission mount , which had Function first yellow sport inserts fitted the inserts were removed and it seems to have sorted the vibration a long hoon tomorrow will confirm this . So I have several questions
1/ why after 12 months of being fitted would these suddenly cause a vibration .
2/ has anyone used the rennline heavy duty transmission bushing on their tiptronic and if so your thoughts please.
It looks like the rennline are a complete bushing rather than an insert they say they are 25% firmer than the stock bushing.
your thought are appreciated as I did like the improved transmission feel of a firmer bushing until the vibration started.
Joined: 30 Jun 2014 Posts: 2170 Location: Warwickshire
Posted: Mon May 15, 2017 8:35 pm Post subject:
That`s a shame Phil, you`ve been over the moon with it for 12 months
Possibly the " plastic " degrading and getting hard over time
Will be following this thread as I`m about to replace my engine and gearbox mounts on the 996 as I can`t see any evidence of them being replaced in the history file. _________________ 1998 996.1 C2 3.4 with "Aerokit Cup"
2006 Boxster S sport chrono
2010 Mercedes E350 AMG Sport
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
That`s a shame Phil, you`ve been over the moon with it for 12 months
Possibly the " plastic " degrading and getting hard over time
Will be following this thread as I`m about to replace my engine and gearbox mounts on the 996 as I can`t see any evidence of them being replaced in the history file.
I know Kris , I coundn't speak highly enough about them , I was thinking the same that somehow the material degraded and lost the give. whereas the rennline ones look like a complete bush alternative so might be the solution I am looking for ,sort of stock but a bit firmer. but wanted to know a bit more before pushing the button on them. I have been pleased with the rennline adjustable semi solid engine mounts so I am hoping the transmission parts will be as good. _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Frenchmeister Suzuka
Joined: 24 Feb 2014 Posts: 1219 Location: Beautiful Cumbria.
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944 Turbo S 88 Solid Black
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Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
Phil, the vibrations started after you had the engine lowered to fix the AC pipe if memory serves me correctly. Surely it has to be linked with this..... - do you think during the process of dropping the engine, a strain was placed on the transmission mount such that it may have dislodged the insert or somehow adversely affected the mount!
It just seems too much of a coincidence that your vibrations started after the engine was lowered, and dropping the engine is surely going to produce an unorthodox effect on the transmission mount.
Nimrod Montreal
Joined: 25 Apr 2015 Posts: 550 Location: East Midlands
Posted: Tue May 16, 2017 6:33 pm Post subject:
Hi Phil
I am sorry I don't have the answer and after fitting semi solid engine mounts have a similar issue at around 3000 rpm.
But I would be careful with Rennline mounts as I found their engine mounts harsher than the RSS ones I am currently using.
In my case I also have a LWF which has been balanced but it was unbearable with Rennline engine mounts which surprised me as I have previously had a solid flywheels with RSS mounts without an issue.
I understand the principle of why stiffer mounts cause more vibration but not why it always seems evident around the point varicam kicks in. _________________ GT4
993 c4s Artic silver Boxster red
997.2 c4s pdk Guards .
997.1 c2s Hartech rebuild LWF RSS mounts sold .
996 c4s Hartech rebuild- sold
993 C2s TorB HID,Dansk 100 Cell Cat, Rss Mounts, PS10's, LWF and GT3 clutch - sold and still missed.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
Phil, the vibrations started after you had the engine lowered to fix the AC pipe if memory serves me correctly. Surely it has to be linked with this..... - do you think during the process of dropping the engine, a strain was placed on the transmission mount such that it may have dislodged the insert or somehow adversely affected the mount!
It just seems too much of a coincidence that your vibrations started after the engine was lowered, and dropping the engine is surely going to produce an unorthodox effect on the transmission mount.
I discussed that Tim with the guys who did it and they said the transmount etc was dropped as a complete unit with the engine as the tip mount is different to the manual one, so it couldnt have dislodged.
So the only conclusion I can come too is that it was just a coincidence that the FF insert became brittle or warped etc at the same time as the engine was dropped _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
I am sorry I don't have the answer and after fitting semi solid engine mounts have a similar issue at around 3000 rpm.
But I would be careful with Rennline mounts as I found their engine mounts harsher than the RSS ones I am currently using.
In my case I also have a LWF which has been balanced but it was unbearable with Rennline engine mounts which surprised me as I have previously had a solid flywheels with RSS mounts without an issue.
I understand the principle of why stiffer mounts cause more vibration but not why it always seems evident around the point varicam kicks in.
I agree with your thoughts of why only at certain RPM strangely I have no issue with my rennline semisolid engine mounts and find them quite compliant but have never been in a car with RSS to compare .
at the moment I think I will leave well alone as after a good hoon today I can confirm all is sorted, vibration gone, so it must have been the FF trans mount inserts. but I will heed your warning re messing with rennline transmission bushing. _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Nimrod Montreal
Joined: 25 Apr 2015 Posts: 550 Location: East Midlands
Posted: Tue May 16, 2017 7:38 pm Post subject:
Probably for the best Phil I am glad you've solved the problem.
I also find it odd that your car with Rennline is ok and mine was shocking.
Fundamentally they are the same car so the vibration should be similar with the same set up. It makes me wonder if there is a connection to how they are fitted or the relationship between the engine and transmission mounts plastics.
I am thinking of getting my transmission mount replaced with standard to see if it makes a difference but would love somebody to explain why its nosiest at the same revs every time. _________________ GT4
993 c4s Artic silver Boxster red
997.2 c4s pdk Guards .
997.1 c2s Hartech rebuild LWF RSS mounts sold .
996 c4s Hartech rebuild- sold
993 C2s TorB HID,Dansk 100 Cell Cat, Rss Mounts, PS10's, LWF and GT3 clutch - sold and still missed.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
Probably for the best Phil I am glad you've solved the problem.
I also find it odd that your car with Rennline is ok and mine was shocking.
Fundamentally they are the same car so the vibration should be similar with the same set up. It makes me wonder if there is a connection to how they are fitted or the relationship between the engine and transmission mounts plastics.
I am thinking of getting my transmission mount replaced with standard to see if it makes a difference but would love somebody to explain why its nosiest at the same revs every time.
one of the first things I did when looking for the vibration was head to the engine mounts , we removed the rennlines and found three things
1/ due to the hole adjustment the engine was sitting 3mm over to one side
unsure if that would affect things but corrected it anyway
2/ the square bolt on the mount was not located correctly in the square engine cut out and was sitting on one edge. this was also corrected .on the rennline the square bolt turns freely which the stock ones don't and the tech had not realised it this was on one side
3/ the other side the square bolt had unwould by 15mm down the spline again the tech was only used to fitting stock ones which wouldnt do that so he hadnt spotted it . when we address all those things I have to say some of the harshness disappeared but the vibration was still there so we carried on looking until we found the issue with the transmission mount inserts.
So whether any of those things had also happened on yours might explain the harshness . just a thought mate also I am running yellow on yellow bushing which is the softest what bushing were you on _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Nimrod Montreal
Joined: 25 Apr 2015 Posts: 550 Location: East Midlands
Posted: Tue May 16, 2017 9:14 pm Post subject:
I was using red/yellow in the engine mounts and like you also suspect that they weren't fitted quite square ,
I intend to recheck the new RSS ones when I have time to ensure they are correctly aligned as I suspect this makes a huge difference to the resonance if not correct.
Thanks for the tips Phil _________________ GT4
993 c4s Artic silver Boxster red
997.2 c4s pdk Guards .
997.1 c2s Hartech rebuild LWF RSS mounts sold .
996 c4s Hartech rebuild- sold
993 C2s TorB HID,Dansk 100 Cell Cat, Rss Mounts, PS10's, LWF and GT3 clutch - sold and still missed.
I was using red/yellow in the engine mounts and like you also suspect that they weren't fitted quite square ,
I intend to recheck the new RSS ones when I have time to ensure they are correctly aligned as I suspect this makes a huge difference to the resonance if not correct.
Thanks for the tips Phil
Maybe the combination of the yellow (softest) and red (hardest) gives a combined compliance nearer the hardest combination which is probably only really suitable for track/race use.
Phil, I think your problem was related to resonance, something possibly being disturbed during the engine drop and being amplified by the normal vibration, maybe something that was put back tighter or looser than before! Annoying though! _________________ Present
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Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
I was using red/yellow in the engine mounts and like you also suspect that they weren't fitted quite square ,
I intend to recheck the new RSS ones when I have time to ensure they are correctly aligned as I suspect this makes a huge difference to the resonance if not correct.
Thanks for the tips Phil
Maybe the combination of the yellow (softest) and red (hardest) gives a combined compliance nearer the hardest combination which is probably only really suitable for track/race use.
Phil, I think your problem was related to resonance, something possibly being disturbed during the engine drop and being amplified by the normal vibration, maybe something that was put back tighter or looser than before! Annoying though!
Rob it was starting to bug me that we couldnt get to the bottom of it , chuffed now its sorted car feels great again _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
I was using red/yellow in the engine mounts and like you also suspect that they weren't fitted quite square ,
I intend to recheck the new RSS ones when I have time to ensure they are correctly aligned as I suspect this makes a huge difference to the resonance if not correct.
Thanks for the tips Phil
If you were running half red which are the hardest ones I am not surprised they felt harsher than the RSS the yellow on yellow is supposed to be the equivalent of RSS so yellow blue might have been a compromise as that's what carreramonkey is running and he likes it
but for the sake of 45 mins work having a double check of your RSS to be 100% they are seated correctly and that the engine is sitting central. _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Nimrod Montreal
Joined: 25 Apr 2015 Posts: 550 Location: East Midlands
Posted: Tue May 16, 2017 10:05 pm Post subject:
I think you guys are right re: red/yellow unfortunately the kit I was initially sent from D911 was missing the other yellow bushes so I went with what I had at the time as Hartech were waiting to put the engine back in the car.
I do think there is something subtle in how these mounts are installed that effects the resonance. On my 993 other than a vibration at idle there was hardly any change from standard more a subtle harder edge to the engine tone.
Currently they are ok and worth the harshness for the improvement in handling but I will recheck them soon. _________________ GT4
993 c4s Artic silver Boxster red
997.2 c4s pdk Guards .
997.1 c2s Hartech rebuild LWF RSS mounts sold .
996 c4s Hartech rebuild- sold
993 C2s TorB HID,Dansk 100 Cell Cat, Rss Mounts, PS10's, LWF and GT3 clutch - sold and still missed.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
Thats just how it should feel a bit firmer but worth it for the improved handling.
there shouldn't be any vibration or excessive harshness. I described it as feeling sort of GT3ish more focused and slightly more mechanical but worth that for the huge improvement and fun driving the car.
It will be interesting to hear what you find when you have checked .
ps dont get me started on service from Design911, beggars belief that you only got a part kit when buying the rennline from them . They are so slack it amazes me they stay in business. I do feel for the Directors of D911 as I am sure they wouldnt want a bad service reputation,they clearly have no idea what a shower of monkeys they have working for them or they would have had a big clear out of the knuckle draggers. _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
Nimrod Montreal
Joined: 25 Apr 2015 Posts: 550 Location: East Midlands
Posted: Fri May 19, 2017 11:38 am Post subject:
Hi Phil
I found 10 mins yesterday when it wasn't raining to have a quick look the mounts and tightened the bottom nut 5 Ib/ft and it has reduced the vibration
Still rougher around 3200 rpm as seems to be the case when these are fitted but it's much better and even the missus admitted it was bearable last night so they are staying
I am thinking of swopping the cheap ssk I fitted for a gt3rs one and changing the gearbox oil so I will get the gearbox mount checked at the same time but for now I am happy . _________________ GT4
993 c4s Artic silver Boxster red
997.2 c4s pdk Guards .
997.1 c2s Hartech rebuild LWF RSS mounts sold .
996 c4s Hartech rebuild- sold
993 C2s TorB HID,Dansk 100 Cell Cat, Rss Mounts, PS10's, LWF and GT3 clutch - sold and still missed.
Phil 997 Brands Hatch
Joined: 05 Dec 2015 Posts: 14298 Location: Bournemouth,Dorset
I found 10 mins yesterday when it wasn't raining to have a quick look the mounts and tightened the bottom nut 5 Ib/ft and it has reduced the vibration
Still rougher around 3200 rpm as seems to be the case when these are fitted but it's much better and even the missus admitted it was bearable last night so they are staying
I am thinking of swopping the cheap ssk I fitted for a gt3rs one and changing the gearbox oil so I will get the gearbox mount checked at the same time but for now I am happy .
Good news that's sorted, I agree everything I have read about the SSK indicates the cheapy ones are a bit notchy and dont like going into gear cold, the GT3 and gt3rs ones dont appear to be SSK as such but are a little shorter but apparently due to metal bearings etc they go into gear no probs and feel really solid on gear change references to loading rifles seems to be how many describe it I am not sure of the difference between the GT3 and GT3RS shifter though and if anyone car enlighten will save me asking in the future _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
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