43 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHHistory of replacement IMS bearing
Leading reported evidence
Replace bearing
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Leading evidence: 'Replace bearing' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check condition of the rms, clutch and possibly the aos' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I replaced the bearing about six months / 5K miles after purchasing (when the clutch started slipping) and determined the OEM dual-row bearing was intact.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
But I repeat...I just want to know people's experience that have replaced a good IMBS.....Good news is allowed......
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
Had 36K miles on and at 37K miles I replaced the IMS with an LN ceramic one.
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Performed · outcome unconfirmed · Original poster
"I replaced my IMS bearing as preventative maintaince.
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Suggestion · Original poster
I wonder if replacing a "good" bearing, after considerable miles, with another bearing indicates that the replacement bearing should last a good long time as well.
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Performed · outcome unconfirmed
I replaced the bearing about six months / 5K miles after purchasing (when the clutch started slipping) and determined the OEM dual-row bearing was intact.
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Suggestion
Just replace the bearing if you wish, change your oil every 5k miles, look for ferrous metal in the filter, and pray to your maker every night that your car doesn't experience this, or one of the 26 other modes of failure.
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43 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
I wanted to get some feedback from those that have the following story concerning their IMS.
"I replaced my IMS bearing as preventative maintaince. I had xx,xxx miles on it, and the bearing looked fine when we pulled it. We put in a replacement bearing".
I am curious. Who has had a IMS failure, after pulling a perfectly good bearing, and what was that solution that you utilized, and how many miles did it take?
In another words, who caused a bigger problem, in the name of "preventative maintaince"? If you haven't had a failure, how many miles do you have on your replacement.
I wonder if replacing a "good" bearing, after considerable miles, with another bearing indicates that the replacement bearing should last a good long time as well. Just a thought I had.
Finally someone is willing to tackle this topic and bring new information to light for the betterment of 996 owners everywhere.
God speed young man. God speed.
I bought my '99 (late '98 build) with approx. 50K miles on it about 4 years ago. I replaced the bearing about six months / 5K miles after purchasing (when the clutch started slipping) and determined the OEM dual-row bearing was intact.
I now have about 80K miles on the car; to my knowledge the LN dual-row bearing is working as expected. The car is currently asymptomatic of anything IMS-related; it does have a couple of other quirks consistent with a car built 18 years ago that has done 80K miles...
TL;DR: 25K miles over 3.5 years on my dual-row LN IMSB w/ no known issues.
Interesting topic. It's a tough balance between 'if it ain't broke' and 'it's kinda broke by design.' The '99 I have has 47,000 miles and is arguably both 'prime candidate' due to garage queen stature, but also 'reliable' because it's a '99.
So I'm torn at the moment. I will first be installing the LNE spin-on oil filter adapter and doing a couple UOA kits before doing any IMSB.
My 10/98 build needed a clutch at 63k miles. I replaced the bearing with an LN as well.
The old one looked great.
In hindsight, if I had done a little more digging around this forum, I probably would have left the original in there.
Oh well, either way. There are only 26 other ways for me to worry about how the motor can fail catastrophically now!
If only some enterprising individual could invert a button that took the person that clicked it to a page that let them search for things. Or better still if they could also invent a way for important and informative threads to be "stuck" to the top of the forum.
If someone could do these things I truly believe we could achieve world peas in my life time!
Please Santa, oh please, bring me a search button and sticky threads. I promise to never ask for anything ever again.
Well, except for that pony you still owe me...
I still consider myself to be a newbie. Got my 2002 NB Cab in August. Had 36K miles on and at 37K miles I replaced the IMS with an LN ceramic one. Shop told me the original looked OK but I feel better having done it. I consider it part of the acquisition cost, still an incredible price for a great automobile. Never thought I could afford a 911 but because of the depressed pricing I now have one!! Thanks IMS. I considered the IMS Solution and while I think that's the best resolution I simply could not justify the cost. My car runs great and I hope that continues for years.
Well....there is a "Search" button at the top of the page. And there are "Sticky" items listed on the 996 Forum. Feel free to play with them. So I assume World Peace is around the corner.
I am not so sure the information I am talking about is presented in the manner that I am asking for it. This is not another "What would you do posting" or " Here is my experience posting", or "Which one is BEST" discussion. I was VERY specific in what I was asking for. If you have a link to another discussion that discussed this in the manner that it is trying to be discussed, feel free to link it. If not.....
As for that pony, Santa has two lists......there is a reason you don't have it.
I always find it best if people are supportive and positive on these forums, vs trying to show everyone how they are wrong. If ya don't like the posting...there are lots and lots of others....Merry Christmas
This kind of goes to my point....everyone that replaces their factory IMS bearing with some type of solution "feels better", but has anyone researched whether or not there is the potential to introduce a failure situation, where the original installation was superior? OR....if the original looked perfect, does it mean that the replacement is less likely to have an issue, due to some external factor, not related to the original bearing?
OP...exactly what are you trying to learn here? Many of us, myself included, have replaced the IMSB as preventative maintenance. If a replacement bearing fails, all you will learn is that the car was doomed to begin with, or the original bearing was already compromised.
Mine at 56K. LNE Retrofit. $1800 plus the clutch and a flywheel. As far as I know, it's happy in Indiana.
Just replace the bearing if you wish, change your oil every 5k miles, look for ferrous metal in the filter, and pray to your maker every night that your car doesn't experience this, or one of the 26 other modes of failure.
Excluding getting T-boned at an intersection.
And like gnat said...you will not learn anything with your post that has not already been discussed ad nauseum...
To be honest, I am not looking to discuss anything. Quite simply...and it really is SIMPLE.....
If your original bearing looked perfect when you did it, how is the replacement bearing holding up? I have not seen that reviewed in great deal.
Not looking for justification, or advice. I guess if the original went to **** before the engine went boom, and the replacement started to go at 30K, then that might indicate that you need to worry more, than if the original looked fine when you replaced it. That is really the only other thing to wonder.
If your original looked fine....do you really need to worry about the replacement? Just a thought....
A few problems with what you are trying to figure out. 1) There is no way to physically inspect the IMSB, oil analysis and checking the filter at change intervals is about all you can do. 2) Same thing for a replacement bearing. 3) If the IMSB fails, it's usually with little or no notice so, could be "fine" now, boom one minute from now.
If your question really is, "Should I proactively replace my original IMSB for piece of mind?", well, like gnat said this is all covered by the search button.
However, you are 100% correct about gnat being on the Naughty List...
I am not trying to figure anything out....REALLY....I'm not.....I just wanted to hear about people's experience.....that is all. I have NO question...other than having people tell me what their replacement bearing has done and how it has acted.
I understand the complexity and danger of trying to determine the status of the IMBS, without removing it. Not even wondering that.....
The ONLY thing that might be of interest is the repeated failure rate of the IMBS, IF....and only If....the original was found to be bad and then it went KA-BOOM with the replacement bearing....BUT....that is not necessarily what is being focused on.
I guess.....one COULD ask...(but I am not asking it), is if you had a good bearing, replaced it with a certain solution....and then that solution went Ker-Powwww! What was that solution....
But I repeat...I just want to know people's experience that have replaced a good IMBS.....Good news is allowed......
[QUOTE=Gonzo911;13833702] If a replacement bearing fails, all you will learn is that the car was doomed to begin with, or the original bearing was already compromised.
QUOTE]
I don't think this is an accurate statement. If your original IMBS looked great with significant miles on it, with no wear issues, and your replacement fails....how does that mean your car was doomed to begin with?
+996,000
1. Not all cars that had an IMSB retrofit had a proper prequal done by a certified shop/tech.
2. There are at least 2 dozen more MOFs that causes CEF...which can rear its ugly head regardless of mileage. Yes, there are many more 996 "killers" out there
3. way too many variables in how a car is driven
4. not all owners use exactly the same oil
5.
ad infinitum/ad nauseam
Above factors (and hundreds more) will EASILY quash any attempt to get usable data to be used as a baseline
Congratulations on not getting sarcasm
So says everyone that starts an IMSB thread with a low post count.
The reality is that the majority of the information you are asking for is indeed in all those other threads. You simply don't want to do the leg work and want us to instead hand it to you on a silver platter.
Of course in creating this thread instead of contributing something useful, you've instead contributed to the very clutter that you new posters complain about.
If you had instead compiled all the information and then presented it for comment, you'd get a more warm response. Instead, like all the others before you, you come with no new information to rehash the stuff that has been beat dead many times before and will unfortunately be repeated many times in the future.
Funny you say that as that is what started my search for a 996 roller originally.
LS swaps aren't cheap, especially if you contaminated the 996 cooling system.
An original IMSB that's lasted many miles, and is removed with no race erosion/ ball spalling is a great indication that the original engine, and IMS assembly didn't come with mis- machined dimensions/ runout.
This alone removes a tremendous amount of the variables associated with the things that kill IMS bearings.
This comment perfectly summarizes what you'll learn from intense reading of the stickies in this forum. This is what makes proof of a "good driver M96" engine.
But you have to spend the money/time to pull and replace the bearing (can't use old one again after pull) so it's a feel-good you have to pay for...
I replaced my IMSB at 101K miles, it seemed in Perfect condition. Then had no problems at all... until the motor imploded. Hope that adds some useful insight.
OP did you think this site was going to be warm and friendly and offer up help to other Porsche owners?
Or, did you think you would be berated and ridiculed for using a site that claims to be for the betterment and sharing of info would be more willing to insult you for trying to get info and be bettered? Well, just don't make that mistake ever again. Take a course on how to use this site and quit wasting our (his) time.
BTW, I understand your question and am glad you asked it. I believe the answer did not adequately exist on this site and still doesn't. More response could get a resolution.
Perhaps people who don't like your question should read it once and then not bother with it a second time much less a third and fourth. They have that choice.
Nice to have you aboard. This site has tons of info and advise just for the asking. Ask away.
I subscribe to my own thoughts and feelings on the subject and while my 996 is sold and I no longer carry the ims worry my thoughts still remain the same. How many engine have been "saved" from a perfectly good bearing? I'll bet hundreds have, in the end I always felt there was a good percentage of fear mongering involved in the aggressive marketing of these bearings. Also the worry is always did the mechanic screw it up and it's now going to fail when otherwise it was in perfect shape? Just too many arguments here to sleep well at night. In the end it I were shopping a 996 I would want one that was n untouched original. I don't subscribe to a lot of the BS "maintainence" items posted on here.
I considered the IMS replacement as part of the acquisition cost of the car. At the same time we were able to check a few other things and carry out some maintenance that would otherwise go unnoticed and undone. All positive in my opinion and not crazy for a 15 year old car that sat a lot during it's life. I now have a reliable crazy fun sports car that I will drive for years without worry. That is the essence of the IMS "issue" in my opinion. As to which one to do, when to do it, consider it a value proposition or smoke and mirrors from IMS replacement vendors is between you, your wallet and your opinion.
So can we deduce that the real problem is a combination of misaligned machining and 15K mile oil change intervals and/or deferred maintainace leading to a load on the bearing causing failure and not the actual fault of the bearing itself? Would the degree of misalignment explain why some fail at 10k miles, some at 100k miles and the majority not at all? Are the engines machined by robot or is there some German dude on the assembly line doing it? If that guy is having a bad day, or stayed out late partying the night before, would that account for varying degrees of misalignment?
How does the old saying go? "Never buy the first car built Monday morning nor the last car built Friday afternoon." Or something like that...However, I understand in the past that in some European factories you didn't want anything built after lunch on any day because of beer lunches!
My view is that if you replace an original IMSB in a car that apparently did not need one, so long as you replace it with a bearing that you believe to be better than the original then you have improved the car. Also should give you lots of peace of mind, not to mention an opportunity to check the condition of the RMS, clutch and possibly the AOS.
The IMSB issue is, in my opinion, one of those things that once you know about it, it is only prudent to act preventively. I'm sure ignorance is bliss for many 996 owners but once you know.....
FIFY
For the OP:
1) I want a 996.
2) I don't want a bad IMS
3) I want to know if the IMS is bad, but I don't want to change it.
4) Or maybe I do, but I don't know if I know if the PO did it.
5) I do want to change it, but I want to know if changing it will make it worse or better.
6) I want to change it, but I want to get an assurance that changing it will make it last better than the orig bearing.
Ever heard of a cat owned by a dude named Schrodinger?
The issue the OP is looking for is partially covered by the concept of a self induced failure mode. And yes, it happens with some regularity. An engine will be disassembled, and rebuilt but with a induced failure in materials or workmanship. Like the bumper sticker says - 'stuff happens'. Infant mortality.
Jake's method with the IMS retrofit process is designed to minimize these kind of failures(I do not work for, or sell any of his or LN products). They cannot be eliminated. A forging flaw in a bearing is hard to discover until it fails. A machining flaw in the shaft is hard to discover once the engine is built because the shaft has to come out and be tested on a bench runout setup.
We know what we know, and likely 90% of what the community knows is covered in the sticky threads above, and the other 5% is covered in various independent threads in the forum. Maybe 5% of the info on the IMS story isn't covered in this forum. Maybe less. They are not always easy to find, but often small nuggets of gold are discovered in a thread that is not stuck. But, it can be searched for, and that is the thrust of this mishigoss with the sarcasm.
The key issues are: 1) there is a flaw which is well known now. 2) there are more solutions avail. 3) the risk of failure after a solution is significantly dependent on the process taken. 4) use good materials, good workmanship and minimize the potential for an infant mortality.
And now a story of infant mortality. I have a friend had a very costly twin engine airplane. It was turbocharged with dual turbos, that's four total turbos on the plane. He took both engines off, had them rebuilt, and had all four turbos rebuilt by an indy shop(the factory was no longer in biz). After assembly and test, the engines were installed, and the plane was flown. Within 30 hours in service, one engine began leaking oil out the exhaust. Within the next 6 hours, the other engine was spitting oil out the exhaust. He also was getting problems with fouling plugs, and rough running. One of the turbos was removed, and inspected and they found both sides of the bearing cartridge loose as a goose, and only hours from catastrophic failure. Upon investigation, he found that the vendor who supplied the rebuild cartridge for the turbos had changed vendors for the iron ring seals, and didn't tell anyone. The new seals came from China, and were branded as coming from a mfg in MA. The iron/nickel seals were beginning to crack and fret allowing the gasses to get past it, and into the bearings, and also the cold side where oil was ingested into the engine. The owner demanded that the engine cyl and top end be taken completely apart, and redone. The cost of this was > $45,000 and the engine rebuilder had to eat the entire thing. I don't know if he tried to pass on the cost to the vendor or not. It could have been even a more costly failure had one or both of the engines failed in flight. Stuff happens.
