Help sorting through the IMS hoopla
09-25-2013, 12:18 PM
#16
Rocky Mountain High
Rennlist Member
Rennlist Member
I appreciate your concerns gnat. Here are the facts:
- All new M96 engines have an intermediate shaft bearing
- The early M96 engines utilized a double-row bearing, while the later designs used a single-row bearing
- There are documented cases of both bearing designs failing
- There are documented cases of high-mileage cars with their original bearing (no failure)
Beyond these facts, everything else is speculation as to whether you are at more or less risk than any other owner of a 996. Some people say the early cars have more failures. Some people say the later cars have more failures. Some low-mileage cars fail. Some high-mileage cars fail. Some cars never see the failure, despite being in what many consider "high risk" situations. There's simply no way to predict it.
Based on the facts above, you have a few choices:
- Leave the original bearing as it is.
- Proactively change your bearing to a ceramic bearing. While this is no guarantee of protection from future failure, it certainly seems to reduce the risk.
- Proactively change your bearing to an OE metal bearing. Some have done this. It's nothing more than replacing a wear item in the engine with a fresh part.
- Install the IMS Solution from LN engineering that eliminates the original intermediate shaft bearing.
I don't think there's really a right or wrong answer here. You simply need to understand the risk/reward of each choice and go with the choice that makes you happy. I believe that the vast majority of 996 owners have never heard of an IMS bearing, and have never done anything about it. The vast majority of them will never experience an issue.
- All new M96 engines have an intermediate shaft bearing
- The early M96 engines utilized a double-row bearing, while the later designs used a single-row bearing
- There are documented cases of both bearing designs failing
- There are documented cases of high-mileage cars with their original bearing (no failure)
Beyond these facts, everything else is speculation as to whether you are at more or less risk than any other owner of a 996. Some people say the early cars have more failures. Some people say the later cars have more failures. Some low-mileage cars fail. Some high-mileage cars fail. Some cars never see the failure, despite being in what many consider "high risk" situations. There's simply no way to predict it.
Based on the facts above, you have a few choices:
- Leave the original bearing as it is.
- Proactively change your bearing to a ceramic bearing. While this is no guarantee of protection from future failure, it certainly seems to reduce the risk.
- Proactively change your bearing to an OE metal bearing. Some have done this. It's nothing more than replacing a wear item in the engine with a fresh part.
- Install the IMS Solution from LN engineering that eliminates the original intermediate shaft bearing.
I don't think there's really a right or wrong answer here. You simply need to understand the risk/reward of each choice and go with the choice that makes you happy. I believe that the vast majority of 996 owners have never heard of an IMS bearing, and have never done anything about it. The vast majority of them will never experience an issue.
09-25-2013, 12:27 PM
#17
Race Director
Q. So is our engine still prone (using the term loosely) to an IMS failure?
A. Yes.
Q. Are the fix options still the same as the later engines that are included in the class action?
A. Your options include:
1) If you have a dual-row IMS bearing, you can replace it with a dual-row IMS bearing.
2) If you have a single-row IMS bearing, you can replace it with a single-row bearing or replace it with the IMS solution.
3) You have the option of installing the IMS Guardian and worry about which route to take if/when a problem develops.
4) You have the option of doing nothing.
A. Yes.
Q. Are the fix options still the same as the later engines that are included in the class action?
A. Your options include:
1) If you have a dual-row IMS bearing, you can replace it with a dual-row IMS bearing.
2) If you have a single-row IMS bearing, you can replace it with a single-row bearing or replace it with the IMS solution.
3) You have the option of installing the IMS Guardian and worry about which route to take if/when a problem develops.
4) You have the option of doing nothing.
09-25-2013, 12:32 PM
#18
Nordschleife Master
Thread Starter
- All new M96 engines have an intermediate shaft bearing
- The early M96 engines utilized a double-row bearing, while the later designs used a single-row bearing
- There are documented cases of both bearing designs failing
- There are documented cases of high-mileage cars with their original bearing (no failure)
- The early M96 engines utilized a double-row bearing, while the later designs used a single-row bearing
- There are documented cases of both bearing designs failing
- There are documented cases of high-mileage cars with their original bearing (no failure)
I believe that the vast majority of 996 owners have never heard of an IMS bearing, and have never done anything about it. The vast majority of them will never experience an issue.
In the end if the real answer is that it should just be considered a wear item that should be changed with your clutch, I'm good with that.
09-25-2013, 12:34 PM
#19
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Just to echo what has been said. It is a regular roller bearing. Some obviously fail more than others (dual row vs single row 996 vs single row unservicable 997). All roller bearings wear out eventually. Replacing it while the clutch is out is not a lot of extra labor and putting the LN bearing in will help your resale. I wouldn't go Krazy and immediately yank the transmission but if you have a clutch replacement looming....why not? I would expect being able to say it has the LN ceramic bearing is probably 1k in resale value.
09-25-2013, 12:35 PM
#20
Rocky Mountain High
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Rennlist Member
That was my approach. I had my bearing changed to a ceramic bearing on my first clutch change, which was at just over 120K miles. According to my mechanic, the original bearing was showing no signs of impending failure.
09-25-2013, 12:59 PM
#22
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Thanks everyone, but this has turned into yet another opinion thread which is not helpful. I'm looking for actual details here so I can make the appropriate judgement.
Please understand that if the engine died tomorrow, we'd put a new engine in it. This isn't about cutting corners or trying to save some money, it's about doing the correct thing (which includes not messing with something that doesn't need to be messed with).
I understand that even if my IMSB is at risk, after 13 years and 70k it's generally accepted that it's probably fine (thus no panic and tear into it if not otherwise needed). I also know that it's not 100% risk free, so change it when we're in there.
I thought the earliest engines (99s? early 00s?) had a different IMSB that wasn't susceptible to the failure (or at least not as much). Is this not the case?
If my understanding is correct (different IMSB in the early years), does anyone have any hard facts about when the change occurred?
I agree that being on that list or not is not a definitive judgement if you are safe or not. Their reasoning for which cars are included is at least as much due to with the lawyers as it was the Techs. It does, however, give me enough pause to question and verify my understanding of the whole issue.
Please understand that if the engine died tomorrow, we'd put a new engine in it. This isn't about cutting corners or trying to save some money, it's about doing the correct thing (which includes not messing with something that doesn't need to be messed with).
I understand that even if my IMSB is at risk, after 13 years and 70k it's generally accepted that it's probably fine (thus no panic and tear into it if not otherwise needed). I also know that it's not 100% risk free, so change it when we're in there.
I thought the earliest engines (99s? early 00s?) had a different IMSB that wasn't susceptible to the failure (or at least not as much). Is this not the case?
If my understanding is correct (different IMSB in the early years), does anyone have any hard facts about when the change occurred?
I agree that being on that list or not is not a definitive judgement if you are safe or not. Their reasoning for which cars are included is at least as much due to with the lawyers as it was the Techs. It does, however, give me enough pause to question and verify my understanding of the whole issue.
The reward of ownership at these prices still outweighs the risk. My thesis is that very soon the IMS fail rates will be less than 1% as solutions become more common, inexpensive, and a part of 996 routine preventative maintenance schedules. This is an iconic car that has been given a unfair rap with these issues and the Boxter front end. Even the nonsense about the head lights is intellectually dishonest and I salivate at the chance to debate a so called "purist" a$$hats about what makes a 911 a real 911. Most people who don't like the "scrambled egg" lights are sheep who were told not to like them. I will never change mine but to each his own.
So in the absence of scientific data and the unlikely possibility that any real data will ever be sampled correctly, one has the following choices:
1. Let it ride and accept the unlikely scenario that you will crap out with a bad IMS
2. Wait until it is time for a clutch replacement and do both
3. Find a lawyer willing to take on a new class action lawsuit (Pro Bono) to include every 996 ever manufactured
I personally purchased a costly power train warranty to get me to 50k miles and my clutch replacement. $166 a month for peace of mind. Given the extreme low purchase price of my car, this warranty is still a great value. I actually hope mine fails in the next two years or 20k miles so that Santa Claus will bring me a new engine.
If not, I plan to do both the clutch and IMS replacement and roll the dice that time will heal the 996 and values will come back up. Heck, whatever else do I have to do with my spare time?
09-25-2013, 02:06 PM
#23
Nordschleife Master
Thread Starter
Either it will go to the junkyard as a total wreck or she'll be buried with it (or maybe both I suppose...). She might not love it more than our son, but I have no doubts about where I stand in the pecking order...
09-25-2013, 02:28 PM
#25
Nordschleife Master
Thread Starter
Me: The Escape isn't big enough to travel with the new baby and 3 dogs, we need to replace it.
Me: ...trying to stay in the $30k range...
Her: Why don't you look at the Cayenne
Me: ...really loves my new P!g even though it required raising my already raised budget...
Nothing like a wife that is more into cars than you are
Edit: And I figure the Cayenne can always bring the 996 home should it find a spot of road where it feels the engine belongs better than under the bonnet
09-25-2013, 03:47 PM
#26
I personally would be loath to drop a high mileage motor in order to stick some after market part in it. Second rule of engineering ... "If it aint broke, don't fix it!" Given the ever falling prices of replacement motors, I consider Ebay to be my insurance policy. And that insurance policy covers ACTUAL engine failures, not just imaginary ones 
09-25-2013, 04:38 PM
#27
Race Director
Well, you're dealing with a bearing (wear part) that has 70k miles and is prone to failure. Generally I am not one to suggest replacing perfectly good parts unless they are very cheap. However, when it comes to a part that's performance controls the fate of your engine and has a reputation for failing, it's worth spending the extra money and replacing that part (OEM or aftermarket) while you have the engine/trans separated.
Do I think it's worth replacing the IMS bearing on its own as a precaution if the engine/trans doesn't have to come apart, no.
Because more cars not on the list have had IMS bearing failures. My '99 original engine fell victim to it. That list isn't the tell all of affected cars, just cars that are the end product of the law suit.
Do I think it's worth replacing the IMS bearing on its own as a precaution if the engine/trans doesn't have to come apart, no.
Because more cars not on the list have had IMS bearing failures. My '99 original engine fell victim to it. That list isn't the tell all of affected cars, just cars that are the end product of the law suit.
Quote:
Originally Posted by golftime
I too am a bit confused by this settlement. First of all, it doesn't appear that my VIN is included (WP0CA29974S650302) although I would appreciate any assistance in confirming this. That said, I am also not sure what it actually means if your VIN is not included, yet your car is pre-2005. Are they saying the problem is limited to a certain production run of bearings, because if so, from everything I have read, Porsche seemed to stick in whatever bearing they had on supply at the time of production. Additionally, for those of us who haven't had the IMS upgrade done yet, if our cars have known defective bearings, it seems silly to wait for an engine failure if Porsche has acknowledged the bearing is likely to fail. By only paying after the bearing has failed, it almost seems that Porsche is waiting us out with a problem they know exists, hoping we get to 10 years or 100k miles first.
By using GMP that comply with the ISO 9000 and 9001 standards they can track by s/n which bad bearing lot # went into which car. So you are not wrong in your thought process but it involved a design change and bad bearings.
Quote:
Originally Posted by Cefalu
What is the basis of knowledge for your opinion?
Reading when they went to the single row design and working with GMP's and ISO-9000 standards.
Quote:
Originally Posted by Mike J
Because they have not included the 1999-2000 cars, nor any cars more than 10 years in service. Most of the 2001-2002 cars will be excluded, and some in 2003 depending when the deliver was made. You telling me that the 1999 and 2000 996's do not have this issue?
They went to the single row design in 2001. So if the 1999-2000 cars all had double row with good bearings then why recall them?
Quote:
Originally Posted by Cefalu
The following paragraph was pulled from the documents posted in the link above which explains the core issue of the lawsuit. Basically, the single row design experienced failures of 4 to 10%, where the dual row design has "far less than 1%"
"Discovery and investigation establishes that Porsche adopted a single row design for the IMS in 2001. The payment of warranty and goodwill claims of owners of Porsche vehicles with this design of the IMS (all Class Vehicles) spiked up to between 4% to 8% of all such Vehicles in the United States, and 4% to 10% of all Class Vehicles in California. Warranty claims for Porsche Boxster and 911 vehicles relating to IMS issues, which had different versions of the IMS, have uniformly involved claims of far less than 1 % of such vehicles. Indeed, to date, Porsche has spent over $20,000,000 reimbursing customers for the parts and labor necessary to repair vehicles experiencing engine damage or failure as a result of the defective IMS shaft. (This entails approximately 3,100 claims granted under warranty or good will.)"
The suit requires that if you suffered a IMSB failure prior to the date of settlement agreement you will have 90 days to file your claim once the settlement agreement is finalized.
The law firm for this matter seem to be pretty experienced in class actions. Interestingly, they have represented many strippers in class action suits against strip clubs in So Cal.
Presumably the acceptable failure rate is less than but not greater than 1% when you read the above. When their rate quadrupled and then went up 10 fold in California lets assume that alarm bells were going of left and right in Zuffenhausen. Based on my experience with some manufacturing design making a rolling change is not an easy thing to do.
I think the discovery documents would indeed be fascinating, but dry, to read. I suspect that Steffan Reinerts , based on the Germanic name, is the Porsche engineer/manager who has the most knowledge of the problem.
Originally Posted by golftime
I too am a bit confused by this settlement. First of all, it doesn't appear that my VIN is included (WP0CA29974S650302) although I would appreciate any assistance in confirming this. That said, I am also not sure what it actually means if your VIN is not included, yet your car is pre-2005. Are they saying the problem is limited to a certain production run of bearings, because if so, from everything I have read, Porsche seemed to stick in whatever bearing they had on supply at the time of production. Additionally, for those of us who haven't had the IMS upgrade done yet, if our cars have known defective bearings, it seems silly to wait for an engine failure if Porsche has acknowledged the bearing is likely to fail. By only paying after the bearing has failed, it almost seems that Porsche is waiting us out with a problem they know exists, hoping we get to 10 years or 100k miles first.
By using GMP that comply with the ISO 9000 and 9001 standards they can track by s/n which bad bearing lot # went into which car. So you are not wrong in your thought process but it involved a design change and bad bearings.
Quote:
Originally Posted by Cefalu
What is the basis of knowledge for your opinion?
Reading when they went to the single row design and working with GMP's and ISO-9000 standards.
Quote:
Originally Posted by Mike J
Because they have not included the 1999-2000 cars, nor any cars more than 10 years in service. Most of the 2001-2002 cars will be excluded, and some in 2003 depending when the deliver was made. You telling me that the 1999 and 2000 996's do not have this issue?
They went to the single row design in 2001. So if the 1999-2000 cars all had double row with good bearings then why recall them?
Quote:
Originally Posted by Cefalu
The following paragraph was pulled from the documents posted in the link above which explains the core issue of the lawsuit. Basically, the single row design experienced failures of 4 to 10%, where the dual row design has "far less than 1%"
"Discovery and investigation establishes that Porsche adopted a single row design for the IMS in 2001. The payment of warranty and goodwill claims of owners of Porsche vehicles with this design of the IMS (all Class Vehicles) spiked up to between 4% to 8% of all such Vehicles in the United States, and 4% to 10% of all Class Vehicles in California. Warranty claims for Porsche Boxster and 911 vehicles relating to IMS issues, which had different versions of the IMS, have uniformly involved claims of far less than 1 % of such vehicles. Indeed, to date, Porsche has spent over $20,000,000 reimbursing customers for the parts and labor necessary to repair vehicles experiencing engine damage or failure as a result of the defective IMS shaft. (This entails approximately 3,100 claims granted under warranty or good will.)"
The suit requires that if you suffered a IMSB failure prior to the date of settlement agreement you will have 90 days to file your claim once the settlement agreement is finalized.
The law firm for this matter seem to be pretty experienced in class actions. Interestingly, they have represented many strippers in class action suits against strip clubs in So Cal.
Presumably the acceptable failure rate is less than but not greater than 1% when you read the above. When their rate quadrupled and then went up 10 fold in California lets assume that alarm bells were going of left and right in Zuffenhausen. Based on my experience with some manufacturing design making a rolling change is not an easy thing to do.
I think the discovery documents would indeed be fascinating, but dry, to read. I suspect that Steffan Reinerts , based on the Germanic name, is the Porsche engineer/manager who has the most knowledge of the problem.
09-25-2013, 06:47 PM
#28
To the OP, heres the link to some more info. Some very informative, some genuis, and some total crap.
https://rennlist.com/forums/996-foru...-and-pics.html
To all other concerned fellow 996 NA owners, what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?
https://rennlist.com/forums/996-foru...-and-pics.html
To all other concerned fellow 996 NA owners, what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?
09-25-2013, 07:14 PM
#29
Race Director
To the OP, heres the link to some more info. Some very informative, some genuis, and some total crap.
https://rennlist.com/forums/996-foru...-and-pics.html
To all other concerned fellow 996 NA owners, what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?
https://rennlist.com/forums/996-foru...-and-pics.html
To all other concerned fellow 996 NA owners, what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?
The crankshafts of some engines were found to have shifted (the crankshaft "cradle" shifted) and often (most of the time) the first symptom was a leaking RMS. A new RMS didn't remain oil tight long. Often the engine just failed.
Early on ( circa mid 2002 ) it was SOP to check the position of the crankshaft's RMS journal prior to replacing the RMS. If the crankshaft position was out of spec the engine was replaced.
My thinking is mis-alignment would have the bearing failing early rather than later.
Also, I talked to a senior Porsche tech who was in the middle of rebuilding a car's engine (under warranty as per Porsche factory) that had experienced a IMSB failure but the driver shut off the engine in time and resisted the urge to try to restart the engine and I asked him a lot of questions. He said that for the engine to be an acceptable rebuild candidate Porsche required certain checks. I won't list them but there was no mentioned made of checking the position of the IMS bearing bore relative to anything else.
He did offer the observation the car was a classic "SF" car. I asked what he meant by this. He replied to the effect the car got driven 5 miles to the office. 1 or 2 miles to a restaurant at lunch time -- to and from the restaurant -- and 5 miles back home at the end of the day.
This suggested to me short trips with resulting oil contamination and subsequent acid build up in the oil resulted in a compromised seal. This by itself is bad enough but maybe not fatal. However the acid that builds up over time attacks the bearing ***** and races and their surface integrity is paramount to their proper function. Also, the acid attacks the bearing cage material, the cage which is critical to maintaining proper ball spacing.
My take away was usage played a role coupled with servicing that didn't mitigate the effects of the usage. A few failures could be attributed to just a defective bearing. It happens.
Last, I would think if a bore was out of position this would be obvious when the engine was being assembled. No one who has done the IMSB upgrade or had it done and to engines which had a bearing that looked on its way to failure has ever reported any issues getting the replacement bearing back in the engine. Also, the replacement bearing would I think be just as affected by the OE bearing and its life be short too.
09-25-2013, 07:31 PM
#30
Drifting
what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?