First time I heard of this theory... IMS
 

In the video below, a comment from user 'Stubahn' claims that IMS failures can be attributed to a certain driving technique from owners who upshift a gear/ or mutliple gears to higher gears when the rpms are too low, thus putting undue pressure on the IMS and eventually that this type of bad driving habit causes the IMS to fail. So it's the driver's fault now. :)

Video of 996 engine failure while on track:
https://www.youtube.com/watch?v=YSCPDYuUYL4

"Zee, zhat's vhat ve bin zaying all along!"

- Porsche M96/M97 Engineers

Actually, that theory is just the simple inverse of the theory you should drive it hard whereas trying to not drive it hard is actually harder on the engine = Driver's Fault

;)

Works fine for me then, as I like to keep her above 3K rpms in all gears normally anyway! :)

It was a bad idea to put an anti-friction bearing in an IC engine.
I believe that higher engine speeds helped lubricate the bearing better after the seal fails. This is why I think that tip cars had more failures but I'm only going on what the local Indy says on that one.

And Stubahm's expertise in this area is what?

If I had a buck for all the theories and fixes that have been advanced, I'd go buy that beautiful 718 I saw yesterday.

Lol... in his comments, he claims that Porsche even sent out a TSB to dealers and certified indys telling them to retrofit certain reinforced bolts to protect the engine from those small percentage of drivers with such bad driving habits that would cause their engines to fail due to upshifting in lower RPMS when they shouldn't. You see!...it's the driver's fault!! :D

Odd...I had read the opposite, that tiptronic cars had less failures.

Theories are like butt holes; everyone has one..........

JFP - I don't have one










A theory that is

LOL, I'll stick with my own theory that things break when they want to be upgraded.

If you replace a part with OEM stock, its just going to have the same problem and fail again.

We have seen many talented innovators on this forum produce upgraded parts that do better than stock in any number of areas.

I suppose carrying this theory to the extreme, we might have upgraded a 986 to the point where it will last forever :)

We have already seen some with 300,00 miles. Thats 12 times around the earth, or the distance to the moon and half way back.

Correct !
It never ends..........

A theory in conflict with another theory? Yes that will never end. :) At least it was based on this Indy's experience of dealing with failed IMS bearings.

Mathematically, this is correct, but only because there are fewer Tiptronic equipped cars......

JFP - some people I know are known to have more than one! LOL

356Guy - I've read that tips have a lower incidence of IMS bearing failure. As far as the higher revs better lubricating a ball bearing based IMS bearing - I'd question that. I remember seeing a Pedro video where he spun an IMS bearing up in oil. At higher RPMs oil is slung out of the bearing and the bearing was shown to be running dry. I won't base a theory on one test, but it sure had me thinking.

I ended up going with Jake Raby's IMS Solution. The permanent nature of the design (it doesn't use ball bearings) made sense to me, plus at higher RPMs there would be increased oil pressure which would better lubricate that type of bearing.

Yeah I saw that demo. I worked in the rotating equipment business for 20 years. Most of the equipment had splash lube bearings which worked very well. Others ran in an oil mist. The bearing needs very little oil. Too much isn't good either. Small amounts of moisture in the oil is a killer too. LN's bearings are open on the exposed side right? They seem to run fine even though the engine was not designed for a splash lube bearing.

ps I'm going to talk myself out of buying a Boxster at this rate :)

Oil pressure is not what keeps the IMS Solution happy, it is oil volume......

Whoohoo - the solution. The only way to save your life.

Well, i'm an expert in cooking water to make a hot beverage - for example bad tasting coffee. And what i can tell you is that cooking water is hot. On everything else i can't say anything.

The only hint i have is to think about "theories" yourself.

Regards, Markus

I think you like cold beverages too :)

And... and.. most of them stink.

Correct
 

Truer words have never been spoken or posted

Why it fails...
 

.....is not important.

All that matters is that some of them DO fail.

What difference does it make as to WHY they fail? Does knowing why your heart stopped beating matter if you just replaced it with an artificial heart?

If you are worried about your IMS, just install the IMS Solution from Jake Raby and get busy living.

:cheers:

To be fair this is bad logic.

It's important to know what can be done to prevent the failure to avoid replacing it.

Imagine how much value the m96 cars would go up if a definitive case was proven that your ims should be fine if you don't lug the engine or you don't corner hard to the left with minimal oil or use this certain oil etc etc.

In the case of the heart I think priority one is to see why it fails before we just ask everyone to put an order in for a replacement just in case.

Can't agree more guys.

I would have sold my Boxster in 2013 if not for the IMS bears issue. And, again last month. Several serious buyers expressed concern. That and I priced is so high. 10/10ths had the right idea. Buy it and upgrade it along with some other parts and enjoy it. Now that I have figured out the Boxster is not going anywhere Ill add the solution to it and be done with it. Now the question is when. Now? When the AOS goes out? When the clutch is done? Fortuitously, I don't lose sleep over it. I have other issues in my life for that!

I haven't changed out the IMS, and won't. I already got my money's worth in the years I've had with my car, and if it goes, the whole car goes, and it's ok. It's served me really well so far, so no complaints. That's not to say this whole thing hasn't intrigued me...it's interesting reading all the theories which is why I posted the link to that guy's comments. What really interests me is how fellow Boxster owner MarcW from PedrosBoard can get over 300K miles now (and still going) on his 02 base 986 with his IMS and clutch still original. If there is an inherent problem with the IMS design, how can some not fail at all?...ever? Why don't they ALL fail if they are flawed? Why only 1% or 8% or whatever the number is? What about the other 92%?....those are unflawed?....

It comes down to risk tolerance. Since there is no definitive cause/s the only prevention is some sort of replacement or upgrade program. Some people can sleep without having the upgrade done and others can't. I wish I were of the later type. I suppose many are oblivious to the issue which is even better. I'm trying to buy a car with the upgrade or at least one priced well enough that it makes sense to get it done. Its interesting to note that all the sellers I've communicated with so far don't believe the upgrade is necessary :)

Did you know...
 

...on a per year basis, your odds of dying in a vehicle crash would be somewhere in between 1 and 4,000 and 1 and 8,000. Currently, roughly 40,000 people per year die in car accidents in the United States.

I won't publish the odds of getting a bearing failure based on the numbers of 986/996 sold because some may feel embarrassed.

With that said, "have fun" and drive safely chaps :cheers:

(and avoid motorcycle road racing if you can)

Probably because they personally have not experienced the loss associated with one failing. When you have to face an owner and tell them that they are facing spending more on his or her dream car than it is actually worth because of a failure, you begin to understand the reality of an IMS failure.

The longer that the failures go on, the more is learned. Early on, no one had any idea what was going on, but much has be learned since then. Several things can potentially either be involved of at least contribute to the issue; suspects include everything from grease wash out to engine cases with off centerline flange bores, and even IMS shafts that wobble because they do not rotate around their true center lines. Contributing to the confusion are competing claims by firms with replacement components; one says it is the bearing itself, another says the bearing is fine, it is lubrication that is the main issue. Yet both can't possibly be right. If you were to step back and think about it, if lubrication was the issue, why don't dual row bearings fail more often than single rows? After all, dual rows have twice the bearing surface area of single rows, so poor lubrication should affect them more often than single rows. Yet published stats from the class action case say that single rows fail 8 to 10 times more often than dual rows. So what is really happening, and whom should you be listening to?

One of the largest contributors to the confusion is that too many accept a single cause on little more than blind faith, rather than stepping back and trying to assess all of the information that is available. The reality of the situation is that there are multiple contributing factors, and while some cars have none of them, while others are not so lucky. Having pulled a lot of IMS bearings, you learn that some come out looking like they are brand new, others with fewer miles on them come out so loose that they acutally rattle when you shake them. Shops that do large numbers of retrofits note some engines that seem to be able to kill just about any type of ball bearing replacements while other seem not to care what type is used. Jake has noted cases of a single engine with multiple failures, so their may be situations where no ball or roller bearing is going to survive because of either multiple causes, or situations such as engine cases with off center flange bores are difficult to spot and even harder to fix. Imagine having to tell an owner that the car he or she drove into your shop that was happily running has failed pre qualification, and that the reason is terminal, requiring an engine replacement.

To say that this is a complicated problem is in itself an over simplification.

Thanks for the post JFP. So what I gather from this is that yes, it's true that some engines are just prone to failure for whatever reason...they are imperfect, while others are in good form, and will not be prone to failure even if upgrades are not applied, and that would explain why MarcW's car hasn't experienced any such issues....he was just lucky he got a perfect example. :)

I was an early adopter.....it's almost time to retro fit the dual row, retro fit if corrosive wear is an issue....Is it? Fresh Motul oil every winter storage; <5000km intervals. I am way under mileage wise.

IIRC one car in the facility undergoing the operation had a failed bearing come out while there...was able to play with failed bearings at the desk....it does happen.

The information I have for five chains: Driving style affects actuation of the vario cam solenoids which affects radial load the ims bearing. The load ramps up every time you drop below 3K as the solenoids phase the cams for low rpm operation. This increased cyclical load could contribute to other factors, precipitating a failure

If you have any question about design flaws, use this tool. Official, and required by DOT to get import/export certifications. Safety only is my guess so if you can't find IMS then you are fine brother :D

https://recall.porsche.com/prod/pag/vinrecalllookup.nsf/VIN?ReadForm=

Nothing like an IMS or oil post. Over 30 entries in 24 hours!

Although it has been discussed in countless threads the IMS issue is always a good read.

BTW, had mine done at ~84,000KM (~52,000M) along with clutch, flywheel and RMS. The original bearing came out 100% fine but doing the work was the best peace of mind money can buy.

......it is wintertime no one is out driving

This is cool info. Thanks! Just checked all my cars, and there's only 1 (for my daily driver Audi (takata airbag pass side), which I got a letter in the mail about already. That def means my IMS is fine cause it doesn't show up at all! :D

LOLOLOL I'll revise my "odds" mathematics... completely forgot about that

It may be impossible to discover which of risk factors that JFP lists your engine has. I have never seen any specific tests to asses which risk factors are present in an M96.
Logically ,the replacement IMSB should be selected based on its ability to protect against all the risk factors - whether they present or not.
Pragmatically ,you just use the best you can justify. And hope.

A buyers dilemma is how to figure out which one you are getting. (at least for low mileage cars)

ps as soon as I ask the sellers about the IMS they seem to lose interest. I'm assuming they have already dealt with inquiries from potential buyers on this.

If you pack the space between the IMSB flange and bearing with grape kool-aid powder, it will never fail. ;)

You got it all wrong, its the citrus powder that works :rolleyes:

I've owned my Boxster for 8 years now and it's seen hundreds of autocrosses and 20 or so track days. I've replaced the ims and the rear main seal, the theory i subscribe to is if you don't change the oil regularly, easpecially if it gets hot the oil losses viscosity and the rear main starts to leak and ends up in the ims. I'll admit I've stretch oil changes before and once did three full (5 hours/day track days), in both instances the new rms started to leak. Changing the oil stops the leak. I think Boxsters are really susceptible to old/worn out oil. If you change the oil regularly I think you're in the clear. This is not a new theory, but I don't think it gets enough attention. Interestingly I run with a group of guys that have all sorts of cars, the Boxster motor has been by far the most reliable. If taken care of I think it can take far more punishment than most engines.