Destructive Torsional Harmonics or How to keep your cam bolts from backing out...
12-15-2019, 03:15 PM
#241
Banned
Originally Posted by hf1
Paradoxically, the most “stretched out” Mezger, the 4.0 rs, is probably the most prone to failures yet by far the most expensive. Not that it matters, as 99% of them will be bubble wrapped as investments.
I'm not up to speed on the instal. I left that to the experts at Sharkwerks but I don't think it requires an engine drop.
12-15-2019, 11:55 PM
#243
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Thanks for the long writeup. I read it carefully. In short, all ICE engines vibrate (some less, some more) and all could benefit from a “dampener” to dampen those vibrations? Is it assumed that Porsche is unaware of the natural resonance frequencies of their engine components or how changing things around (bore, stroke, mass of moving parts) changes the frequencies at which the engine vibrates?
There may be a simple statistical explanation for the lower (reported) incidence of Mezger engine failures after the dampener was introduced. As Mezger car prices bottomed and started firming up in 2012-13, many of them started to get driven less, especially on track, and treated more as “investments”. Also, don’t know the exact numbers, but if out of say 5000 (2004-12) Mezgers out there, 500 received a dampener, then the number of reported failures with a dampener would still be 1/10 of the number of reported failures without a dampener, even if the dampener did nothing to solve the problem. Plus, not every Mezger owner is on RL.
The TLDR from all this for me is to keep my 3.6 Mezger 996 gt3 with DMFW and enjoy it as is. Banished the thoughts about “upgrading” to SMFW and other RS bits, or to a 7.2 RS at >2x the price.
Maybe Mezgers should have stayed 3.6 and under 400hp. Trying to squeeze out more performance than that may come with exponentially higher risks of failure. Not surprisingly, that’s the point (2012) when the Mezgers were put out of (street) production. They could be stretched no more.
Paradoxically, the most “stretched out” Mezger, the 4.0 rs, is probably the most prone to failures yet by far the most expensive. Not that it matters, as 99% of them will be bubble wrapped as investments.
There may be a simple statistical explanation for the lower (reported) incidence of Mezger engine failures after the dampener was introduced. As Mezger car prices bottomed and started firming up in 2012-13, many of them started to get driven less, especially on track, and treated more as “investments”. Also, don’t know the exact numbers, but if out of say 5000 (2004-12) Mezgers out there, 500 received a dampener, then the number of reported failures with a dampener would still be 1/10 of the number of reported failures without a dampener, even if the dampener did nothing to solve the problem. Plus, not every Mezger owner is on RL.
The TLDR from all this for me is to keep my 3.6 Mezger 996 gt3 with DMFW and enjoy it as is. Banished the thoughts about “upgrading” to SMFW and other RS bits, or to a 7.2 RS at >2x the price.
Maybe Mezgers should have stayed 3.6 and under 400hp. Trying to squeeze out more performance than that may come with exponentially higher risks of failure. Not surprisingly, that’s the point (2012) when the Mezgers were put out of (street) production. They could be stretched no more.
Paradoxically, the most “stretched out” Mezger, the 4.0 rs, is probably the most prone to failures yet by far the most expensive. Not that it matters, as 99% of them will be bubble wrapped as investments.
Man of all our posts, I didn't think 5 years later I'd be facing the level of denigration and snarky sarcasm we are in this one... That said I'll do my best to restrain myself and answer the questions...
Yes all ICE have torsional oscillations and harmonics of those oscillations that will be excited by inputs.
To dampen those oscillations you need to add mass and a way to dissipate the oscillations energy. Two weighted metal plates, one fixed to the crank the other joined to the first by an elastomeric ring works great as the elastomer acts as a energy transfer device, converting mechanical energy into heat... ATI has built a business around this...
Do Porsche's engineers know... I would assume someone knew, and they rolled the economic dice. They've known about this harmonic issue since the 962...
Big corporations exist to make money...
Some other things Porsche may have known about but did nothing:
996/997 glued in coolant fittings coming loose,
IMS,
991 GT3 finger follower
As far as the analysis of the issue goes, and explanation that "it's skewed statistics governing the dampers efficacy" and that the damper essentially does nothing... knock yourself out. Data is data, just a bunch of stuff sitting out there until someone decides to make sense of it... For what it's worth the previous explanation for why cam bolts were coming out was a lack of loctite... seems that didn't work out well for those that bought into it.
There are plenty of engine builders that use our dampers as they have been personally burned by not using them. We even have some real super star skeptics using them at Rothsport Racing on his air-cooled builds. His quote was something like, wow, the engine dyno used to vibrate like crazy now it's nice and smooth, and we picked up some power as well... And those engines are ending up in some pretty darn expensive Guntherworks 993's...
In the end, you vote with your money, buy it, don't buy it, your choice. We'll keep making them and offering them to those that want them.
Was good to see you Steve...
__________________
Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
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Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
www.dundonmotorsports.com
Facebook.com/dundonmotorsports
Instagram @dundon_motorsports
Last edited by Jamie@dundonmotorsports; 12-16-2019 at 02:58 PM.
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Steve2k1116 (12-17-2019)
12-16-2019, 12:55 AM
#244
This business is about identifying a problem and creating a solution. You cannot convince everyone. My days are full of way too many important things to achieve and take care of, than trying to convince those that do not understand or agree.
Don't fit ANYTHING to your car or engine unless you understand why you are doing this.
We looked at what engine issues we saw and had incurred ourselves and what solution we thought was the better one. If you are not having any issues, do nothing and enjoy the car. Unfortunately others have not been so lucky and the damper has solved their problems.
If you knew the problems many of the high end OEM's have, you may have a different point of view. Even their current flagship models, undergo many recalls and campaigns, some you shake your head at and ask, "how come", don't they test these cars anymore. The only answer to many of these on-going issues can only be, testing is limited by budget and the solution will be addressed superficially under warranty. As soon as the warranty period is over, you the car owner will pay.
PD and Dundon identified and came up with a solution to the 991.1 GT3 finger issue. I know we were correct in this as the 991.2 GT3 engine changed over to what we had done as a solution.
I/Dundon are not the answer to all issues, but it appears that we are the only ones that have attempted to supply an engineered solution to many of them.
Don't fit ANYTHING to your car or engine unless you understand why you are doing this.
We looked at what engine issues we saw and had incurred ourselves and what solution we thought was the better one. If you are not having any issues, do nothing and enjoy the car. Unfortunately others have not been so lucky and the damper has solved their problems.
If you knew the problems many of the high end OEM's have, you may have a different point of view. Even their current flagship models, undergo many recalls and campaigns, some you shake your head at and ask, "how come", don't they test these cars anymore. The only answer to many of these on-going issues can only be, testing is limited by budget and the solution will be addressed superficially under warranty. As soon as the warranty period is over, you the car owner will pay.
PD and Dundon identified and came up with a solution to the 991.1 GT3 finger issue. I know we were correct in this as the 991.2 GT3 engine changed over to what we had done as a solution.
I/Dundon are not the answer to all issues, but it appears that we are the only ones that have attempted to supply an engineered solution to many of them.
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Jamie@dundonmotorsports (12-16-2019)
12-16-2019, 08:31 AM
#245
Rennlist Member
Man of all our posts, I didn't think 5 years later I'd be facing the level of denigration and snarky sarcasm we are in this one... That said I'll do my best to restrain myself and answer the questions...
Yes all ICE have torsional oscillations and harmonics of those oscillations that will be excited by inputs.
To dampen those oscillations you need to add mass and a way to dissipate the oscillations energy. Two weighted metal plates, one fixed to the crank the other joined to the first by an elastomeric ring works great as the elastomer acts as a energy transfer device, converting mechanical energy into heat... ATI has built a business around this...
Do Porsche's engineers know... I would assume someone knew, and they rolled the economic dice. They've known about this harmonic issue since the 962...
Big corporations exist to make money...
Some other things Porsche may have known about but did nothing:
996/997 glued in coolant fittings coming loose,
IMS,
991 GT3 finger follower
As far as the analysis of the issue goes, and explanation that "it's skewed statistics governing the dampers efficacy" and that the damper essentially does nothing... knock yourself out. Data is data, just a bunch of stuff sitting out there until someone decides to make sense of it... For what it's worth the previous explanation for why cam bolts were coming out was a lack of loctite... seems that didn't work out well for those that bought into it.
There are plenty of engine builders that use our dampers as they have been personally burned by not using them. We even have some real super star skeptics using them at Rothsport Racing on his air-cooled builds (crazy it happens on an air-cooled engine too? Oh crap the sky really is falling....). His quote was something like, wow, the engine dyno used to vibrate like crazy now it's nice and smooth, and we picked up some power as well... And those engines are ending up in some pretty darn expensive Guntherworks 993's...
But I'm sure you're right... it's just a statistical anomaly and the folks working the issue and all the folks that have used it and tested it over the last 5 years are all lemmings
In the end, you vote with your money, buy it, don't buy it, your choice. We'll keep making them and offering them to those that want them.
Yes all ICE have torsional oscillations and harmonics of those oscillations that will be excited by inputs.
To dampen those oscillations you need to add mass and a way to dissipate the oscillations energy. Two weighted metal plates, one fixed to the crank the other joined to the first by an elastomeric ring works great as the elastomer acts as a energy transfer device, converting mechanical energy into heat... ATI has built a business around this...
Do Porsche's engineers know... I would assume someone knew, and they rolled the economic dice. They've known about this harmonic issue since the 962...
Big corporations exist to make money...
Some other things Porsche may have known about but did nothing:
996/997 glued in coolant fittings coming loose,
IMS,
991 GT3 finger follower
As far as the analysis of the issue goes, and explanation that "it's skewed statistics governing the dampers efficacy" and that the damper essentially does nothing... knock yourself out. Data is data, just a bunch of stuff sitting out there until someone decides to make sense of it... For what it's worth the previous explanation for why cam bolts were coming out was a lack of loctite... seems that didn't work out well for those that bought into it.
There are plenty of engine builders that use our dampers as they have been personally burned by not using them. We even have some real super star skeptics using them at Rothsport Racing on his air-cooled builds (crazy it happens on an air-cooled engine too? Oh crap the sky really is falling....). His quote was something like, wow, the engine dyno used to vibrate like crazy now it's nice and smooth, and we picked up some power as well... And those engines are ending up in some pretty darn expensive Guntherworks 993's...
But I'm sure you're right... it's just a statistical anomaly and the folks working the issue and all the folks that have used it and tested it over the last 5 years are all lemmings
In the end, you vote with your money, buy it, don't buy it, your choice. We'll keep making them and offering them to those that want them.
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Fisher (12-16-2019)
12-16-2019, 10:41 PM
#247
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What a thread. Still no data/evidence/tests showing these harmonics and how installing a dampener dampens them?
So 996.2, 997.1, and 997.2 gt3 (with DMFW) don't have this problem, while 997.1 and 997.2 RS both do? Or is this just a 997.2 RS problem?
No shop (most of them Porsche and GT/Cup car specialists) has ever mentioned anything about this issue with my 996 GT3.
What "harmonic problems" do these engines have? First time I'm hearing about this.
Again, what are the preventative solutions and how much do they cost? Losing a Mezger engine over smth like this would not be "fun".
Started reading that thread. Not a mechanical engineer but still an engineering PhD here (with good grasp of harmonics and Fourier analysis) and had hard time following the OP's description of the problem and the "dampener" solution.
So Porsche has been making and racing Mezger engines for decades -- hundreds of Porsche engineers dumbfounded for decades about how to resolve a known "harmonic" vibration problem, then someone solves it by putting a "dampener" to dampen these vibrations? OK, let me continue reading the thread...
So Porsche has been unaware for decades that they could change the harmonic (frequency response, resonance) properties of a dynamic system by adding, removing, or redistributing mass around? No one told them...
Thanks for the long writeup. I read it carefully. In short, all ICE engines vibrate (some less, some more) and all could benefit from a “dampener” to dampen those vibrations? Is it assumed that Porsche is unaware of the natural resonance frequencies of their engine components or how changing things around (bore, stroke, mass of moving parts) changes the frequencies at which the engine vibrates?
There may be a simple statistical explanation for the lower (reported) incidence of Mezger engine failures after the dampener was introduced. As Mezger car prices bottomed and started firming up in 2012-13, many of them started to get driven less, especially on track, and treated more as “investments”. Also, don’t know the exact numbers, but if out of say 5000 (2004-12) Mezgers out there, 500 received a dampener, then the number of reported failures with a dampener would still be 1/10 of the number of reported failures without a dampener, even if the dampener did nothing to solve the problem. Plus, not every Mezger owner is on RL.
So 996.2, 997.1, and 997.2 gt3 (with DMFW) don't have this problem, while 997.1 and 997.2 RS both do? Or is this just a 997.2 RS problem?
No shop (most of them Porsche and GT/Cup car specialists) has ever mentioned anything about this issue with my 996 GT3.
What "harmonic problems" do these engines have? First time I'm hearing about this.
Again, what are the preventative solutions and how much do they cost? Losing a Mezger engine over smth like this would not be "fun".
Started reading that thread. Not a mechanical engineer but still an engineering PhD here (with good grasp of harmonics and Fourier analysis) and had hard time following the OP's description of the problem and the "dampener" solution.
So Porsche has been making and racing Mezger engines for decades -- hundreds of Porsche engineers dumbfounded for decades about how to resolve a known "harmonic" vibration problem, then someone solves it by putting a "dampener" to dampen these vibrations? OK, let me continue reading the thread...
So Porsche has been unaware for decades that they could change the harmonic (frequency response, resonance) properties of a dynamic system by adding, removing, or redistributing mass around? No one told them...
Thanks for the long writeup. I read it carefully. In short, all ICE engines vibrate (some less, some more) and all could benefit from a “dampener” to dampen those vibrations? Is it assumed that Porsche is unaware of the natural resonance frequencies of their engine components or how changing things around (bore, stroke, mass of moving parts) changes the frequencies at which the engine vibrates?
There may be a simple statistical explanation for the lower (reported) incidence of Mezger engine failures after the dampener was introduced. As Mezger car prices bottomed and started firming up in 2012-13, many of them started to get driven less, especially on track, and treated more as “investments”. Also, don’t know the exact numbers, but if out of say 5000 (2004-12) Mezgers out there, 500 received a dampener, then the number of reported failures with a dampener would still be 1/10 of the number of reported failures without a dampener, even if the dampener did nothing to solve the problem. Plus, not every Mezger owner is on RL.
Waited for a while to write back, even tried to add some more data to the thread to appease/inform, but the knocks kept coming. Maybe I'm reading something that's not intended to be there, but the repeated use of quotes around dampener, harmonic etc..., and the repeated statements of Porsche being unaware for decades led me to belief that a change in tone of my response was necessary.
Not always the best sales process to fight fire with fire, but the internet now a days it's pretty easy to find a phone number of a vendor and make a call if your interested in asking questions...
Those that have worked with me or know me, know that informing and resolving issues if there are any is what we try and do (do unto others and all), but sometimes repeated provocation can get under my skin a bit.
12-17-2019, 08:06 AM
#249
Rennlist Member
Jamie, sarcasm (mine above) doesn't always translate. Separately, I'm glad your product for this potential design flaw exists and I appreciate the explanation of the problem and a solution you offer.
I have 4.0 and a 3.6 engines, both with LWFW. I realize these things are just machines and anything can happen, but does the 7.1rs with standard 7.1rs clutch/ LW-flywheel (not upgraded to 4.0 like they typically eventually are) pose a similar threat that it's larger brothers have? It seems like someone on here described an engine grenade from similar issue in a 7.1rs. At the same time, most of the discussion I've had with people "in the know" on this issue claim, anything can happen, but the 3.6rs (including lwfw) doesn't pose the same level of threat on this. Thoughts?
I have 4.0 and a 3.6 engines, both with LWFW. I realize these things are just machines and anything can happen, but does the 7.1rs with standard 7.1rs clutch/ LW-flywheel (not upgraded to 4.0 like they typically eventually are) pose a similar threat that it's larger brothers have? It seems like someone on here described an engine grenade from similar issue in a 7.1rs. At the same time, most of the discussion I've had with people "in the know" on this issue claim, anything can happen, but the 3.6rs (including lwfw) doesn't pose the same level of threat on this. Thoughts?
12-17-2019, 11:18 AM
#250
Jamie, thanks for all of the detail. Does the base 997.1 GT3 3.6 with standard flywheel that is stock pose any threat? I guess there is always a chance, but would it make sense to do the dampener during a service or possibly when doing coolant lines? I am sure it would not be a bad idea, but if the likelihood is ridiculously small, I think money could be better spent elsewhere. Thoughts?
Thanks!
Joe
Thanks!
Joe
12-17-2019, 09:36 PM
#251
Rennlist Member
Any incidents on 997 GT2 RS? That’s 3.6 w single mass flywheel (from 964 RS I believe). I had the 964 RS single mass flywheel on my 3.6 turbo. No problems-
(also have had 4 mezger cars no coolant leak either. Lucky - and knock wood. )
If it’s limited to 3.8 RSI might do after my warranty period ends, in any event - good work.
(also have had 4 mezger cars no coolant leak either. Lucky - and knock wood. )
If it’s limited to 3.8 RSI might do after my warranty period ends, in any event - good work.
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Robocop305 (11-25-2021)
