Vertex Auto and its Permanent IMSB Upgrade
09-22-2015, 03:23 PM
#47
Rennlist Member
Since I deal with studies and statistics all the time, here's my take on this:
According to the only statistics with a large enough sampling to be considered halfway reliable, the class-action-suit stats, even the OEM small single-row IMSB left untouched has only an 8% failure rate. That's the original, low-load-capacity sealed steel bearing where the seal gets breached, filled with dirty oil turning the grease into grinding paste. Only an 8% failure rate. 92% of cars with the weakest most ill-conceived IMSB fitment do not fail.
All a "solution" needs to do is reduce the probability of failure by a measely 8%.
According to the only statistics with a large enough sampling to be considered halfway reliable, the class-action-suit stats, even the OEM small single-row IMSB left untouched has only an 8% failure rate. That's the original, low-load-capacity sealed steel bearing where the seal gets breached, filled with dirty oil turning the grease into grinding paste. Only an 8% failure rate. 92% of cars with the weakest most ill-conceived IMSB fitment do not fail.
All a "solution" needs to do is reduce the probability of failure by a measely 8%.
Reducing the 8% failure rate by only 8% would reduce the overall failure by 1% or so. The 8% failure needs to be reduced by 100% to be a success.
But, I think I understand your point that all the IMSB solutions out there are addressing a part that is not likely to fail, statistically.
But Schnell has the correct perspective that the 8% or 10%, etc. number shouldn't be used in the way that it often is.
All components in any engine built will theoretically fail at some point, and there is really no benefit to over-engineering any specific part of an engine for longevity past an engine's useful life.
However, this marginal engineering sometimes leaves too little room for error and leads to specific parts to become known as weak points of the engine.
Porsche engines have had a variety of weaknesses over the years, and aftermarket solutions have been a source of business for decades.
It's only when a part is under-engineered (or poorly made) that the part gains everyone's attention, and it's no wonder that there are several entrepreneurs out there that are trying to capitalize on the repair/replacement market.
Who's solution is better, who's is best, who's is "good enough"?
It makes for interesting conversation, and the engineer in me likes to understand each product's particular means and methods.
It would be nice if Vertex would respond to their own thread though....
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RobertM525 (05-16-2021)
09-22-2015, 03:40 PM
#48
Hello everyone, thank you for your questions and comments. I was expecting to see just a few comments and questions, but apparently the IMSB has a bit of a controversial history.
There are a series of very technical questions that I will address but will not do so at a technical level like I do in the academic research world. The responses are intended to address questions but not develop a treatise in engineering, mathematics and physics. Sorry, but this forum is for the Porsche 996 enthusiast and I want to respect that. Additionally, I want to make it clear that we are providing the 996 community with a service, specifically information about our product and are not defending it. Some information is proprietary and required many hours of research and development to fully understand and create the product, but its success speaks for itself.
Data tells us that the use of spherical ball bearings in the IMS is not an appropriate application. Porsche used three variations of ball bearings and all have had catastrophic failures. Indicating that this design was not the correct choice initially and through two subsequent reengineering attempts. In our engine rebuild program we used upgraded Porsche IMS bearings along with aftermarket ball bearing types with forced lubrication and there continued to be failures in those. One can conclude that ball bearings of any configuration in the IMS will fail. Please check out this video for further explanation https://vimeo.com/87596816.
The initial research on the axial and radial movements and tolerances was developed from the cylindrical roller bearing specifications used on Porsche transmissions. The goal was not to make an improvement to the original roller bearing IMS design but to correct it, and our experimentation and R&D to achieve that objective moved us away from the spherical ball bearings Porsche was using to the cylindrical roller bearings. No magic or creativity was needed to develop our product’s specifications, just science. Axial and radial forces are greater in racing transmissions than they would be for the intermediate shaft bearing application, but we found that the radial loads were the critical ones of concern. And this was discovered by inspecting and measuring the varying degrees of damage in pre-blown bearings. This was how we identified the etiology of the damaged bearings, the pressures exerted on the bearings, and the type of movement that was happening between the races. This allowed us to understand radial, axial and thrust tolerances and further develop the specifications of the cylindrical bearings. In the end, science lead us to choosing the cylindrical bearing. By the way, if there are any questions regarding the veracity of using cylindrical roller bearings in the IMS application, our patent is on the thrust control set up and the number is 9004766.
Regarding our highest mileage since IMSB installation, as you know most 996s are not typically daily drivers but we monitor a number of 996s and 986s with about 60,000+ miles since the install of their Eternal Fix. Those are our very first installations, but the product specifications remain the same. There are probably higher mileage cars out there, but we do not have access to that information because they are not local, or the IMSB was sold to other shops for installation, or we have not been maintaining other higher mileage Porsches with our IMSB. If these were Toyotas, the scale would be much greater and the higher mileages would be easily attained. I can tell you however, that our local IMSBs are inspected on a regular basis in our customer’s cars to obtain QI data and feedback.
Regarding the comparison of the ball bearing designs, 12 cylindrical rollers cover more surface area than a single or double row of 8 spherical ball bearings. In the 996 application, the measured load surface area for an 8 mm ball bearings is only 2mm while the measured load surface area for a 15mm cylindrical bearing is a theoretical 15mm. Double the row of ball bearings and you get two rows of 2mm surface area. As mentioned earlier, the science guided us to cylindrical bearings for this application. We experimented with spherical ball bearings initially, but the data did not reveal the outcomes we were hoping for.
Regarding oil pressure after the Eternal Fix upgrade, since a new orifice has been introduced internally there is a change of ½ PSI down. This is not detrimental, and as a reference in oil pressure 10PSI per 1000rpms is acceptable in this application. Our data shows the ½ PSI change is continuous and stable at cold start, hot start, idle, 1000 RPMs, 2500 RPMs, 5000 RPMs. Above 5500 RPMs we found the oil pressure to equal the Pre-IMSB upgrade status.
Regarding oil, this is probably the most important subject discussed with our customers and dealers. Clean oil and 996s are synonymous with engine longevity and critical to keeping the IMSB intact. We recommend Porsche approved oils and filters with changes occurring every 4500-5000 miles or 6 months whichever comes first. That recommendation changes with climate and if your vehicle is near South Florida then we recommend sticking to the 4500-5000 miles or six months whichever comes first model.
Regarding the question about oil fragments getting stuck, if you are changing oil and filter as recommended above with fresh Porsche approved oil, then debris will not develop. However, if debris as large as the 2mm opening has invaded your crankcase, then there may be other problems to worry about.
Regarding the question about the first generation 987 and 997, the Eternal Fix does fit those cars. More complicated to install than the pre 987 and 997s as a hole is bored through the IMS area using pressurized air in the crankcase which effectively prevents metal fragments from entering the crankcase. Even though the process looks ugly, it’s actually very precise and accurate. For a visual explanation please see the Vimeo video at: https://vimeo.com/118923581.
I hope I was able to answer the majority of questions.
There are a series of very technical questions that I will address but will not do so at a technical level like I do in the academic research world. The responses are intended to address questions but not develop a treatise in engineering, mathematics and physics. Sorry, but this forum is for the Porsche 996 enthusiast and I want to respect that. Additionally, I want to make it clear that we are providing the 996 community with a service, specifically information about our product and are not defending it. Some information is proprietary and required many hours of research and development to fully understand and create the product, but its success speaks for itself.
Data tells us that the use of spherical ball bearings in the IMS is not an appropriate application. Porsche used three variations of ball bearings and all have had catastrophic failures. Indicating that this design was not the correct choice initially and through two subsequent reengineering attempts. In our engine rebuild program we used upgraded Porsche IMS bearings along with aftermarket ball bearing types with forced lubrication and there continued to be failures in those. One can conclude that ball bearings of any configuration in the IMS will fail. Please check out this video for further explanation https://vimeo.com/87596816.
The initial research on the axial and radial movements and tolerances was developed from the cylindrical roller bearing specifications used on Porsche transmissions. The goal was not to make an improvement to the original roller bearing IMS design but to correct it, and our experimentation and R&D to achieve that objective moved us away from the spherical ball bearings Porsche was using to the cylindrical roller bearings. No magic or creativity was needed to develop our product’s specifications, just science. Axial and radial forces are greater in racing transmissions than they would be for the intermediate shaft bearing application, but we found that the radial loads were the critical ones of concern. And this was discovered by inspecting and measuring the varying degrees of damage in pre-blown bearings. This was how we identified the etiology of the damaged bearings, the pressures exerted on the bearings, and the type of movement that was happening between the races. This allowed us to understand radial, axial and thrust tolerances and further develop the specifications of the cylindrical bearings. In the end, science lead us to choosing the cylindrical bearing. By the way, if there are any questions regarding the veracity of using cylindrical roller bearings in the IMS application, our patent is on the thrust control set up and the number is 9004766.
Regarding our highest mileage since IMSB installation, as you know most 996s are not typically daily drivers but we monitor a number of 996s and 986s with about 60,000+ miles since the install of their Eternal Fix. Those are our very first installations, but the product specifications remain the same. There are probably higher mileage cars out there, but we do not have access to that information because they are not local, or the IMSB was sold to other shops for installation, or we have not been maintaining other higher mileage Porsches with our IMSB. If these were Toyotas, the scale would be much greater and the higher mileages would be easily attained. I can tell you however, that our local IMSBs are inspected on a regular basis in our customer’s cars to obtain QI data and feedback.
Regarding the comparison of the ball bearing designs, 12 cylindrical rollers cover more surface area than a single or double row of 8 spherical ball bearings. In the 996 application, the measured load surface area for an 8 mm ball bearings is only 2mm while the measured load surface area for a 15mm cylindrical bearing is a theoretical 15mm. Double the row of ball bearings and you get two rows of 2mm surface area. As mentioned earlier, the science guided us to cylindrical bearings for this application. We experimented with spherical ball bearings initially, but the data did not reveal the outcomes we were hoping for.
Regarding oil pressure after the Eternal Fix upgrade, since a new orifice has been introduced internally there is a change of ½ PSI down. This is not detrimental, and as a reference in oil pressure 10PSI per 1000rpms is acceptable in this application. Our data shows the ½ PSI change is continuous and stable at cold start, hot start, idle, 1000 RPMs, 2500 RPMs, 5000 RPMs. Above 5500 RPMs we found the oil pressure to equal the Pre-IMSB upgrade status.
Regarding oil, this is probably the most important subject discussed with our customers and dealers. Clean oil and 996s are synonymous with engine longevity and critical to keeping the IMSB intact. We recommend Porsche approved oils and filters with changes occurring every 4500-5000 miles or 6 months whichever comes first. That recommendation changes with climate and if your vehicle is near South Florida then we recommend sticking to the 4500-5000 miles or six months whichever comes first model.
Regarding the question about oil fragments getting stuck, if you are changing oil and filter as recommended above with fresh Porsche approved oil, then debris will not develop. However, if debris as large as the 2mm opening has invaded your crankcase, then there may be other problems to worry about.
Regarding the question about the first generation 987 and 997, the Eternal Fix does fit those cars. More complicated to install than the pre 987 and 997s as a hole is bored through the IMS area using pressurized air in the crankcase which effectively prevents metal fragments from entering the crankcase. Even though the process looks ugly, it’s actually very precise and accurate. For a visual explanation please see the Vimeo video at: https://vimeo.com/118923581.
I hope I was able to answer the majority of questions.
Last edited by RodVertex; 09-27-2015 at 10:30 PM. Reason: Formatting and grammar
09-22-2015, 05:55 PM
#49
Rod, thanks for answering some of the questions. I wish you had more info on the thrust control as that seems to be the most mysterious and contentious topic. I think you are over worried about being too technical. I'm sure there are a handful of engineers, mechanical or otherwise on this thread who can understand and comment on the math, physics, etc.
Based on my understanding, I see some potential issues:
1) Since the oil supply is not filtered, it's easy to pick up some debris (e.g., worn pad material) from the bottom of the sump via the oil pick up tube, which feeds the oil pump directly. The debris may block that small (1-3mm) hole rendering the oil supply ineffective
2) The bearing is basically glued to the intermediate shaft by red loctite and no circlip is used to fix it in place
3) Using the outer race bearing surface as a plain bearing. This is quite creative but also unconventional. Not sure if the outer race design has accounted for that.
Based on my understanding, I see some potential issues:
1) Since the oil supply is not filtered, it's easy to pick up some debris (e.g., worn pad material) from the bottom of the sump via the oil pick up tube, which feeds the oil pump directly. The debris may block that small (1-3mm) hole rendering the oil supply ineffective
2) The bearing is basically glued to the intermediate shaft by red loctite and no circlip is used to fix it in place
3) Using the outer race bearing surface as a plain bearing. This is quite creative but also unconventional. Not sure if the outer race design has accounted for that.
Last edited by Ahsai; 09-22-2015 at 06:11 PM.
09-22-2015, 06:09 PM
#50
Rennlist Member
Rod thanks for the info....you state "spherical" and "ball bearing" in the same sentence. A spherical roller bearing is much different from a single (or double) row, deep groove, ball bearing, which is what the description is of the IMSB. I'm sure you know this, but want to point this out to others.
Single row, deep groove ball bearing:
Double row, deep groove ball bearing:
Roller Bearing:
Spherical Roller Bearing, Double Row:
Single row, deep groove ball bearing:
Double row, deep groove ball bearing:
Roller Bearing:
Spherical Roller Bearing, Double Row:
09-22-2015, 06:11 PM
#51
Three Wheelin'
Just thinking out loud, but I would think that's a snuggish fit anyway so the Loctite is just there to be safe. If its' going to move it will in the bearing, or it should, unless it's a really loose fit.
IMO thinking out loud.
09-22-2015, 06:42 PM
#53
Why did you use a roller bearing over a spherical roller bearing. The other end of the shaft is held in place with a journal bearing. Inherently, you will get a little "play" because that's the nature of a journal bearing. (Clearance needed for fluid film) Intuitively, this just seems like the perfect application for a spherical (roller) bearing since it's self aligning.
I'm a systems analyst for a company that designs and manufactures bearing propulsion systems for the Navy's submarines. While the application is different and I'm not as knowledgeable with the M96, I've studied tribology extensively. In my opinion, you need to give us a better answer than "you got your answers from science." Otherwise, you're going to come off as another company attempting to profit off fear mongering. Any CAD jockey can throw together an assembly, and you need to prove you have an understanding of tribology before you expect anyone to bet a replacement motor on your product.
Sorry if this came off as bitchy.
09-22-2015, 06:47 PM
#54
Three Wheelin'
Hey Rod,
Thanks for the extended explanation and additional information.
Do you think you could add in some carriage returns in your posts and break it into a few paragraphs?
It would make it so much easier to read.
Thanks
Thanks for the extended explanation and additional information.
Do you think you could add in some carriage returns in your posts and break it into a few paragraphs?
It would make it so much easier to read.
Thanks
09-22-2015, 08:17 PM
#55
Race Director
09-22-2015, 10:15 PM
#57
Ugh I stated it in a really dumb way. Of course what I meant was, any "solution" only needs to address an 8% failure rate, not a 25% or 50%.
09-22-2015, 10:18 PM
#58
But why go through all the trouble of thrust control if at the end the bearing itself is glued to the IMS and can be dislodged by thrust? I know what you're after but it still feels not very robust without a circlip.
09-22-2015, 10:30 PM
#59
Data tells us that the use of spherical ball bearings in the IMS is not an appropriate application. Porsche used three variations of ball bearings and all have had catastrophic failures. Indicating that this design was not the correct choice initially and through two subsequent reengineering attempts.
In our engine rebuild program we used upgraded Porsche IMS bearings along with aftermarket ball bearing types with forced lubrication and there continued to be failures in those. One can conclude that ball bearings of any configuration in the IMS will fail.
I am not saying the cylindrical bearing is no good, it may very well be just as good as the ceramic, but I can't see any unbiased evidence that the ballbearing itself is inadequate. I can see an argument that the plain bearing (The Solution) offers at least a theoretical advantage over either ballbearings or cylindrical bearings, as it has fewer moving parts.
09-22-2015, 11:28 PM
#60
Drifting
Rod at Vertex seems to be engineering challenged?
"Data tells us that the use of spherical ball bearings .." There are ball bearings with non-spherical ***** ?
"the spherical ball bearings Porsche was using.." What? Instead of what ?
This just gibberish. I just unsubscribed because if the developers of the part can't even use the correct terminology but claim all kinds of research the BS meter pegs.
"Data tells us that the use of spherical ball bearings .." There are ball bearings with non-spherical ***** ?
"the spherical ball bearings Porsche was using.." What? Instead of what ?
This just gibberish. I just unsubscribed because if the developers of the part can't even use the correct terminology but claim all kinds of research the BS meter pegs.