1999 with double row ims vs single row
 

Is it safe to say the '99 has a low incidence of ims failure. At less than 1%.
The rate of failure with double rows looks to be over 8%.

I'm having a ppi done on a '99 boxster this weekend Been reading up on the common issues Not sure but it seems like less than 1% is almost a non issue . Less than 1 out of 100. I may be misinterpreting these statistics ??

Preventative measures are frequent oil changes , proper viscosity , quality filters,
Magnetic drain plug , driving at rpm's 2500 & up checking filter for metal.

Any others? I was ready to look other choices for sports car BMW etc. but think the
Internet may have induced ims panic ! I don't like to gamble but the odds seem pretty good

I'm no expert, but I have been pretty busy with Boxsters over the last couple years. Since August 2014, I have owned five 1999s and a pair of '01s that all have dual row bearings.
The '99s range in mileage from 80,000 to 175,000. As far as I know only one of them has had the IMS bearing replaced and I did it because the seal was leaking. The bearing itself was still good at 129,000 miles. I got the dual row LN ceramic replacement.
One of the '01s had a failed engine at 124,000 miles with a broken rod/rod bolt. The IMS bearing still looked good, but had lost the grease. The other '01 was a parts car for the replacement engine. While I had it out, I replaced the bearing (which still looked good) with the bearing from Pelican Parts. After five years or so, I may replace it again.
Dual row bearings have failed, but lots of other parts are more likely to fail first IMO. Continue to search and read, there's lots of good info and much of the info here on the forum is experience and reality based rather than hype. If worrying about it is likely to ruin your enjoyment of the car, don't buy it, or simply have the bearing replaced.

Be sure you are comfortable with spending more than the old car is worth in repairs. If you want a cheap, reliable, easy to fix roadster, there are more prudent choices than an older Boxster.If you do buy, a Boxster make sure you don;t overpay. Good Luck- they are great cars if you have the skills,tool,equipment, facilities, time and funds to keep them.

99s came with double row bearings and these had failure rates if <1%. It was the single row cars that saw higher rates.

Your maintenance suggestions are spot on, but you face a double whammy.

The root cause of the problem seems to be when the bearing seals allow the lubricating grease to wash out over time but don't allow enough oil back in to adequately lubricate the bearing. When this happens, the bearing - whether single or double row - will fail.

Seals can degrade on high AND low mileage cars. Whammy 1: seals in high mileage cars just plain wear and eventually leak. It's a question of when. Whammy 2: seals in low mileage cars start to leak when acids in the oil degrade them when part of the seal just sits in the oil.

If your buying a high mileage car, you'll probably need a clutch soon so just replace the bearing at that time. If your buying a low mileage car, the calculus is harder b/c you just won't know the condition of the seals. Then you just hope the <1% stands up

Hi,

there are lots of causes why theses engines can fail. IMSB is only one. My personal POV: there are some people interested in making money by spreading fear. ;)

And as long as you have oil sucked in the IMS you have a kind of lubricated IMSB – just think about it – it rotates. ;)

I have a 2003 S (US = 2004) and i'm very happy with it, because it hasn't the old variocam camshaft mechanism with the green seals and the camshaft rails that desorientate.

Also it has the better designed cylinder heads.

On the downside there are the weaker open deck 3.2 cylinders. But with the right oil, permanent oil changes and slowly warming up the engine i think that is manageable. We'll see when it fails.

Also think about that an IMSB can be installed the wrong way. It was not intended to be changed by factory. So if somebody does it, he needs to know what he is doing and i'm pretty shure it is important to use the right tools and methods and be careful to get a durable result. And in general: if you find magnetic parts in the oil it's too late for just doing an IMSB. Maybe it's a good idea to install a new IMSB with every new clutch.

Don't see why i should only drive at 2.500 rpm and above.

And if the engine fails it fails. That's life.

Also agree what Gelbster said. The expensive part is the proper maintenance of the car. Even if you don't buy every replacement part at the Porsche d(st)ealership – which you have to do sometimes and if you do repairs yourself.

BTW: we've had a lot of 2.7 FL engine failed, but no 3.2 FL in the last months in the german Porsche forum. Fingers crossed. ;)

Regards, Markus

The failure rate is quite low as has been written already. I did a major refurb on our 2000 and replaced it as a preventive measure when replacing the clutch. There are many threads about what to look for on a new buy and what the fix might cost.

Deferred maintenance on these cars can be quite expensive if you can't do it yourself. Does the car have service records?

the current owner has had car for over 10 yrs . says he changes oil every year , he averages less than 3000 miles / yr . I'll see what other records he has

I can see how things will wear or rot on a 17 year old car [ sounds old !]
that being said it's hard to find a car with so much upside for under $10k
I've had -MG, Miata , corvette , BMW 330Ci, new Boxster [2004] -
Boxster was the best handling with plenty of power [it was an S]

I may need to become more involved with maintenance- oil / brakes etc. Maybe there is a Porsche club in my area [long island NY ]

When I purchased my red boxster I chose a 99 because it seems to be the IMS proof one and it has a few upgrades over 97's and 98's for me a 99 is the best option in terms of longevity but is it my opinion and based on my research.

1% was reported as part of the settlement with car owners years ago. Yet people show up here every week with bearing failure (mine is dual row and failed).

It's not 1% any more.

Correct..........

A different perspective is interesting.
 

Markus,
Your perspective is interesting because you are involved with a Porsche M96 world that is closed to most of us because of language. The English-speaking world gravitates to the American based forums so we seldom discover differences and nuances in say Germany/Austria/Switzerland
A specific example is the IMSB issue. From what little I can read on German Porsche forums, the cylindrical roller bearing is quite a popular alternative and was used much earlier than here in the Anglo Porsche world. Is that true? And which specific version of the cylindrical roller bearing is used? Do they all use the SKF NUP204 bearing or local equivalent? I ask because we all made such a fuss about "thrust control" when Vertex introduced it here.But I do not find that issue discussed in Germany. This is interesting because RND in the U.S.A. make a big deal about this.
Roller Bearing IMS Retrofit Kit – RND Engines
Here is the alleged German alternative with no mention of thrust control from a "colorful" source:
http://www.mbmotorsportsrepair.com/items-for-sale.html
The vendor has a questionble reputation on Forums but perhaps his German-sourced products are indeed good?

Does the way people drive effect the longevity? I think of my neighbor with his new ford f150. Son blew the motor a couple months into ownership. Father blamed ford, I blame son. I see how he drives and know of other things he had destroyed. He's a maniac.
I don't think Boxster's are 0-60 cars but if they are treated as such, could that negatively impact the motors life. I thought I read some place that it was designed with the u.s crowd in mind so maybe I so could be wrong.

It's a tough choice to drop 2k on an ims for a 10k car.

David

I'm thinking the ims bearing should be a routine replacement at xxx miles
like a timing belt .
I'm sure after a certain amount of miles anything can fail . Bearings fail & the imsb was obviously not well thought out as far as lubrication goes .

Huh. That's odd.

Yup,it is odd. And Markus may be able to give us some insight.
The German EBay kits and the roller bearing kits discussed on the German language Forums do not mention thrust control. Some mention the large washer (you see this in the RND photos) but I have never seen a photo of a German kit with a large washer + a claim for improved function due to thrust control.
We hammered Vertex on this issue and they eventually modified the text of their roller bearing blurb to mention thrust control .
Some of the European kits are just USA imports ,so I am ignoring them for this discussion

Hello Gelbster,

to be honest, most independent Porsche engine rebuiders i know in the Stuttgart and Germany area use all ball-bearing ISMBs that are like the OEM design. They say replace it with every clutch and use the right oil and change the oil yearly. Why is that? Because the other solutions are quite too expensive.

Might be different calculation for an AT car. But it also seems that AT cars fail less from an ISMB. But they also fail. Cracked heads, failing tensioners, oval cylinders from overheating, hydrolocking… you know better than me what else can fail. ;)

The roller bearing ISMBs are not that popular, because of the same subjects. They generate more friction, so the generate more heat. And because the IMS is running at the same rpm than the engine, these types of bearings are more at their limits than ball-bearings. Just check the specs of the roller bearing manufacturers. An remember that the engines revs higher than the max. rpm given at max. power. Mine revs up around 6.900 rpm until it hits the rev limiter while max. power is at 6.200 rpm in my S.

Thrust control is another topic. Most people think of engines as a static system. But they are installed in a car with engine part torques, drive train torques, g-forces in cornering, acceleration, braking, road bumps… So you have additional mass moments. And concerning the valve train and IMS most of these masses are compensated by the IMS bearing and IMS bearing mount.

The M96 engines that failed very early from an ISMB had mostly engine case problems (986 and 996). And these engines were all replaced by Porsche with new OEM engines. In general they didn't repair them, they replaced them. So there was a cause for that. ;)

There are IMSB kits with oil feed. From my POV this is more discussed im germany forums. What happens if the oil feed fails and is it useful to use oil pressure for an additional oil feed, when the oil system wasn't designed for that. The overall opinion is not to use additional oil IMSB feeds in this specific engines.

But you also keep in mind that in Germany the cars are used in a different way than in the US. We have also speed limits but we have also parts on the Autobahn where we don't have speed limits. You have the tail of the dragon – mostly with speed limits. We have the alps and the Black Forest with an official speed limit of 100 Km/h on normal roads. But who cares. :D ;) Maybe race tracks seems to be similar. But there are also climate differences. We don't have that very warm summers like you have in Texas or Arizona. So maybe there is a lot different that can affect an engine oil system and cooling system.

IMSB kits. OK, there is lot of stuff around, because there is much fear and so you can do a lot of money out of kits that contain some stuff you and me can buy and manufacture for 50-100 bucks in a limited edition. Also the guys are Porsche drivers, so the only know Porsche prices and will pay them. The more expensive the better. ;) What does Made in Germany exactly mean. Does it mean the bearing is made by FAG or anybody else in Germany. Or does it mean the whole components are designed and made in Germany. Reminds somehow on Apple. Designed in Cupertino, made in Asia at the cheapest fabrication facility they could find. ;) Which doesn't mean the products can fail because they are badly designed by supplier parts – i know what i'm talking about when it comes to Apple graphic cards with Nvidia or ATI chipsets. ;)

The MB Motorsports IMSB seems to contain parts from NTN which is located in Germany but has production factories all over europe. For example in Romania, Russia - where production costs are cheaper. And if you take a look at the extraction tool i would say go for the latest LN extraction tool.;)

As for the RND engines kit. The manual looks good. Hope everybody uses it. Heard of some DIY people that didn't lock camshafts/crankshaft and didn't remove tensioners. Saw it lately in a video. You can imagine the results. Don't see why Made in Japan should be less good than Made in Germany.

I know one kit that is really designed and made in Germany. That is by FVD Brombacher and has ceramic ball bearings. But that doesn't mean it is better or less good than others. And it is also not cheap (Porsche drivers don't care about money ;) ) - around 470 Euros without toolkit.

In the end i would say go for a local manufacturer. Because first it is no rocket science. And second it doesn't make sense to pay a lot of money for shipping, taxes and duties to import things. If you have an excellent ball or roller-bearing manufacturer in the US or where you live, why not use local stuff?

And as always, these are just my 2 cents. Maybe other people have other opinions. Maybe other people read other forums or have other sources and background. There is a lot of information (and misinformation) around. So just my 2 cents.

Regards, Markus

OK, here is the part that is missing: For some time, it has been known that not all of the IMS shafts were created equal; some spin true, while others have shown significant run out, which causes the shaft to wobble and literally beat the Hell out of the bearings. I think Jake first picked up on this when he examined engines that had multiple IMS bearing failures. Others mistakenly identified the issue as a thrust problem with the ball bearing design, leading to the development of the roller bearing replacements, which in fact have no better load carrying capacity that the ceramic ball bearings, and do not in my opinion really offer any better performance in a high run out shaft.

Unfortunately, the only way to test the shaft for run out is to take it out of the engine and test it on the bench, making testing in the field a non starter. And this run out issue may factor in to why some dual rows fail, while other go on forever. All of this went into Jake's development of the IMS Solution, which is decidedly more tolerant to run out in the shaft than any other style bearings, and which should outlive the rest of the engine as well.

Not so much.
http://i1045.photobucket.com/albums/...ps3745da07.jpg
The IMS runs at a much lower speed than the crankshaft, as is evident in this picture I took while I was enjoying the innards.

Hello JFP in PA,

this wobbling problem is causal caused by bad engine case adjustment (hope that is the right term). In general these engines were replaced by Porsche completely. Well known problem.

flaps10: you're right. I have to go into this further because i remember there where some differences in different M96 engines. Maybe i'm wrong… have to take a look into the tech docs.

Regards, Markus

I'm sorry, but you are not correct. On shafts with this issue, if placed in fixtures outside the engine and then turned while a dial indicator tracks them at the bearing end, the run out can be substantial, to the tune of over 0.010 inches. This is in the shaft itself, with nothing else involved. Over time, the repeated wobble in an assembled engine can reek havoc on the IMS bearing.

I followed the "runout" threads elsewhere with interest.
Interesting to see the runout is 10 thou" (0.254mm). That is new info for me.Seems like it should be part of a thorough rebuild check. Too late for me and Flaps - next time perhaps !
Interesting how the discussion eventually comes back to the same remedy despite flirtations with alternatives.

Replacing the IMS is like getting a Flu shot. Get the shot one less worry. Or don`t get one and hopefully you won`t get sick.
I had mine done around 133 kms. Dual row.

Hello JFP in PA,

OK, let's go more into that. I think we're talking about the same problem, but maybe there are multiple causes why this could happen.

First of all let us compare the designs of Porsche intermediate shafts of that time. I know most of us will know the differences, so this is also for those who are new.

Fact is, the 986 2.5 engine was the first engine with an IMS tube (August 1996). Also it was the first flat six water cooled production engine in the Porsche engine line. 993 and 996 Mezgers have a different designed IMS. The 996 engine was presented with the new 996 model in 1997.

I have never heard failing a Mezger engine from a IMS failure by the IMS itself. Why is that? Because the IMS is designed completely different. It's based on a solid rod with gears and on each side it has an oil feeded plain bearing. It's a short designed construction.

996 Mezger engine (water cooled)

http://986forum.com/forums/uploads02...1475167412.jpg

993 engine (air cooled)

http://986forum.com/forums/uploads02...1475167441.jpg

In the M96 engines this is completely different designed. The IMS is a long hollow tube, that transmits power from one end of the engine to the other to drive the camshaft drivetrain which actuates the hydraulic ilfters and the valves of this side of the cylinder head. It has gears on each side and the gears are simply pressed "on" the tube. One side of the tube has a plain bearing. The other side has a ball-bearing with a mounting mechanism. So there is a lot of torsion force on that tube.

986 engine

http://986forum.com/forums/uploads02...1475167475.jpg

Personally i'm shure that every IMS was inspected before installed and get though a quality test. I don't think an engine manufacturer will build an engine that doesn't last and by that will cause an immense amount of additional costs. I also think it's well designed, means that the engineers did know what are they doing when they dimensioned parts and material quality.

Why they did use a grease filled sealed roller-bearing IMSB? I don't know. It seems to be the weak part, but there are also engine that lasts 200.000 miles without any problems - even with single row bearings. And i would say that is a very good life expectancy for a high revving sports car engine.

But the engine design was made in the start of the Wiedeking era and i think that caused a big change in the companies culture. Because from that moment every little part was cost driven and a team of pedantic financial controllers were installed to check the engineers work. And if you take a detailed look at the engine production process (casting, Lokasil…) you'll find a big amount of changes in the production process that were cost driven. The good side: it safed the company.

Thoughts why an IMS can start to wobble?
1. bad IMSB that affects the integrity of tube and gears (just remember: on one side is a plain bearing)
2. torsion overload that effects the tube of the iMS - for example by hydrolock, valve hits head…
3. torsion overload that effects the gear of the IMS - same as above
4. material fatigue
5. installation problem when exchanging an IMSB
6. problem with IMSB mount
7. problem with geometry of the 2 engine cases (or is it block?) used for the crankshaft / IMS - mostly installation fault. Cases are CNC machined.

My information from german forums is that number 7 caused most of the early engine failures and these engines where replaced completely by Porsche. Personally i would say maybe on the cause for the failure.

I'm shure i could explain that better and more detailed in german language. Hope the words make sense.

As always just my 2 cents.

Regards, Markus

You are missing the point. Brand new, unused M96 shafts, right out of the box can demonstrate this run out. Shafts removed from running engines with perfectly good IMS bearings show run out to varying degrees, while many well used M96 shafts show no or very little run out at all. On top of this, the shafts from used M97 engine's do not show this tendency.

So basically, if you got an M96 with a shaft with run out, and it happened to be a single row engine, the odds were stacked against you being a happy camper.

Markus,
You have a welcome & different perspective than the rest of us because you have access(via language) to different information - the German-speaking Porsche Forums. I try but stumble at Lagerdeckel !
This is important because I notice a difference even between U.K. and USA forums.Because our ideas here are developed in isolation we are vulnerable to 'drinking our own Cool-Aid'
Your list of 7 IMSB problems/causes is interesting.I have never seen such a list before. The pragmatic question is - what can we do about it?
Any of the 7 issues ,if severe enough will eventually cause IMSB failure. Let's suppose I have a still-running engine with one or more of these issues(but have no way of measuring it). I remove my original OEM IMSB at 90K miles and find the seals 'blown, the tube with oil in it, the bearing a little wobbly, no ferrous debris in the filter or pan. I have 'caught; it just in time.
So what do I replace the IMSB with - suspecting I have one or more of the 7 deadly problems with the tube?
The answer is - the most fault-tolerant bearing available - The Solution.But will it pass "Pre-Qualification" for Pro installation+warranty??
If not ,what to do ? The second best choice is debatable - as are the tolerances for all the 7 deadly IMSB sins in your list and the way they do/do not interact to cause premature failure of the IMSB.
I guess the second best choice is DIY install of "The Solution" in this scenario or a cylindrical roller bearing if on a budget?
Thank you for your interesting perspective that may clarify this mystery a bit more.

Here is a hint of how to qualify a would-be M96 engine rebuilder: "Would you let me see the IMS runout test on my shaft?
And what about the other 6 items on the list of 7 supplied by Smallblock
My guess is that only well equipped and trained machinists would be able to do this test.The average engine rebuilder would not have the correct equipment ,nor even know what to look for.
The pragmatic suggestion is to use a new M97 shaft when rebuilding an old M96 ?How else do you buy an M96 shaft that is straight? Then you do not need such a fault-tolerant/expensive bearing ?Dang - I did not know this when I rebuilt mine - next time.....:-)

Sorry Markus, I don't mean to pick on you. This is a great, healthy discussion and I just want to make sure that some assumptions die where they should, so thanks for contributing to the discussion.

CNC machinery (which I've spent my entire working career around) only make it possible to make the same exact mistake a shocking number of times. People like to assume that CNC means perfect when compared to an old man on a 100 year old conventional mill or lathe. Accuracy and repeatabilty are functions of machine rigidity (stiffness) and not the black box hanging on the side of the machine giving orders.

The case halves are cast (and rather poorly if you examine them), which are then machined in several operations before they are assembled into an engine. Each time you remove the casting from one machining operation a human puts the casting into the next machine. There is room for error and variation every time you touch the part, and depending on how the part is "registered" (that is, how they pick up previously machined features to index the next operation from) it can have a huge effect on the consistency of the finished product.

A loose chip in the fixture will cause variation, a cutter that is getting dull or has runout, how tight one operator clamps the part in the fixture compared to another guy, etc. I've seen marks in a part after a train went by the shop I worked in at the time and older machines could just take a left through the middle of a part on a hot day for no reason.

IMS runout doesn't surprise me since the thing is pressed together, and having a sprocket slip isn't uncommon.

Gelbster, If you have removed your ims bearing at 90 K , found it a little worn ( to be expected ) but still ok , and no ferrous metal in the filter or sump , then the engine with regard to the IMSB is running just fine . So then for peace of mind , why not just treat the bearing as a replaceable maintenance item and install a new bearing of the same type ,[ without seals ] after all the original has done 90k without failure. The original bearing is a $10 bearing , the "Solution " is in excess of $2000 .The critical point to note is that it should be replaced as early as possible in the life cycle of the engine . It seems to me to be a situation of a very expensive sledge hammer to crack a very small nut.
JFP, When you talk of IMS run out I guess you are meaning that the shaft ( tube ) is either bent or not round or both to a max of .010"?

"The critical point to note is that it should be replaced as early as possible in the life cycle of the engine "
And in a perfect (Porsche) world we would love to know how to time that so perfectly !
Pray tell us !
This is a reality thread. It is about mitigating risk. And as far as cost is concerned a good total rebuild from IMSB failure is $7000+. And that is just parts and equipment-assuming the engine can be saved.That is the number that matters ,not the $10 for the bearing.
So discussing any cheaper option = be it The Solution or a cylindrical roller bearing like NUP204 is obviously valid. Replacing with the same failure prone part when we are still discovering causal factors does nothing to mitigate risk.
And it is runout not out of round. The 2 are obviously different. The IMS is bent not squished.

The cost benefit calculation for the IMS Solution is multi faceted. First, and perhaps most importantly, it is a permanent fix that never needs replacement. So if you plan on keeping the car for a longer period, you need to consider the cost of multiple IMS retrofits vs. the one time cost of around $1700 for the Solution. Secondly, the IMS Solution is tolerant of conditions that no other retrofit would tolerate, such as high run out shafts. As I keep my cars for a long time (my daily driver, purchased new, will turn 20 next year), when I retrofitted both my and my better half's M96 cars (both purchased new), I did not even consider another choice, they both got IMS Solutions (one dual row, one single row), and I could not be happier with the outcome. And as we do PPI's for customers, I can also tell you that buyer's are aware of the value of the IMS Solution as well. People tend to forget that even a quality IMS retrofit that has 60K miles on it looses some of its value at resale, as the buyer has to factor in doing it again in the foreseeable future. The IMS Solution does not.

When I refer to run out, I am looking at how true the surface that hold the IMS bearing stays as the shaft rotates. Exactly where the movement comes from is a more complex issue than just bending. Because the bearing mount surface is machined into the shaft, its center line may not be on the shaft's center line, which could give you a straight shaft that turns true, but that is not what the bearing sees. Some shafts may also not be true themselves (perhaps from the process of pressing the chain gears on), causing the same issue even if both centerlines coincide. And while I have obviously not personally seen the numbers of these units that Jakes has, he has shown photos of shafts where the run out was well beyond 0.010 " and mentioned how he has had to develop screening procedure's to test shafts going into the engines he builds. Just another one of the joys of the M96 engine.

Hello,

Hi Gelbster,

well first of all there is a myth that the IMSB never was designed to be replaced while the engine is in the car. Because there is no official Porsche special tool offered? Simple question: would some shurely not too dumb engineers would have designed the mount and bearing this way?

Best solution:
There are different aspects. I think everybody has to decide himself what he or she wants to do and what amount of investment and risk to take.

Pre qualification: i completely understand why there is that process. If you have hard metal debree in a soft full aluminium engine with Lokasil coated cylinders you have a major problem. Some of these engines will still run for some time (maybe if you're lucky and the metal debree amount wasn't high forever), but sooner or later you can run into problems. A new IMSB will not solve the problem. And as said there are a lot more causes why the engines can fail.

Cost:
Does it make sense to put a 2K-3K solution in a 10K car? Would you think one minute if it would be a 100K car?

On the other side:
A 986 engine rebuilt in Germany starts at about 12K Euros and grows up to about 15-20K Euros for a more optimized engine.

An used 986 engine is available at about. 3-4K Euros. But you'll never know what you get. And to make it a good one you also have to put some additional money into it precautionary.

Installation:
From my personal POV an installation can definitely go wrong if not done properly.

Perfection / perfect world:
If you want to make 100% shure that there is no problem you have to rebuilt the engine every 50K miles. :D But as always - also a rebuilt engine can fail sometimes.

Conclusion:
I don't have a solution for that.

My personal opinion:
A proper installed high quality roller ISMB with every clutch replacement. And if your DMF is worn even if the clutch isn't, replace the DMF, clutch and IMSB all together. And: if the engine fails, it fails - there are a lot of causes why the engine can fail. IMSB is only one.

As for installation and quality tests.

@ JFP in PA: If you have got new parts from Porsche that are out of tolerance, sent them back, tell them what you found and ask them to sent you a new part.

I see a lot of causes why a new part can be out of tolerance. Example: i lately ordered some Brembo brake pads in Italy (around 600 miles to my home). I asked kindly to package everything very safely before shipping. What did the idiots do. They throwed the OEM packaged brake pads (just put in a card box) in another card box and shipped them this way. The result is expensive garbage you can throw into a trashcan.

Also there are tolerances. These engine parts are mass production. Pistons and rods are not equally weighted before installation. Crankshafts are not finely balanced… If you want a 100% perfect spec engine you'll need to bring it to the 100% perfection yourself or by somebody else. Not to mention you'll need the machinery and know how to do it – in your case i have no doubts that you can do it.

@****Gelbster: For the DIY man who is doing a repair or engine rebuild in you own garage (like you did) i don't think there is a simple way to get everything perfect. Shure with time, know how and patience you can build a really good engine. But you need very expensive machinery and also know how to do and test some things. One solution could be to bring the parts to a local machinery shop and let them do the tests and optimization for you.

@ flaps10. That is what i've wrote / meant. The aluminium engine case is made by an aluminium cast. Then it was CNC machined. Then it was Lokasil coated. Think i've wrote that, no problem at all. If there is something misleading or not understandable just ask. My english skills are just the way they are. Always a problem to be exact and precise for me.

I agree that CNC machining doesn't mean there can be faults and errors. But if you take a look at modern engine production plants you'll find the processes everywhere. Also every 986/996 engine at Porsche were assembled by skilled and educated mechanics. So there was a quality control by eye and also by machines that controlled the results - shurely not at todays standards.

I could go more further in that production process, but i think that would be much to much for that post and honestly it would take me a long time to translate the terms and processes precisely.

@ JFP in PA: These are interesting aspects.

Let's calculate some things:
LN premium solution: $1700 plus professional installation or premium tool $600 and plus cam locking… tools plus DIY. I would estimate 2.5K plus.
Conventional high quality ball bearing plus new updated mount: $200 plus materials for tools made yourself $50. I would estimate $ 250 plus.

Clutch needed around every 60-70K miles. AT-car - other calculation.

IMS run out:

I'm not an engine engineer, but i think it's an interesting aspect. Is a ball bearing capable to handle more IMS tolerances than a plain bearing? I did a research and from what i understood i would say yes.

@ all / for those who are interest in bearing technologies and want to get more into it:

Some infos about bearings in general (english language)
Schaeffler Germany | Products & Services | Rolling and Plain Bearings

Some infos about roller bearings (sorry, only german language)
Technische Grundlagen

Regards, Markus

PS: If you have access to a spare engine and a 3D scanner and a 3D construction program you can do funny things.

OK, let’s look at your comments, point by point:

The “myth”: The reason for the “myth” that the IMS bearing cannot be changed without disassembling the engine happened because Porsche notified US dealers in writing that this was the factory’s official position on the subject. US dealers had been pleading with the factory for a fix for what was rapidly becoming a major issue influencing North American sales, with many pointing to Jake Raby and LN Engineering’s then newly announced retrofit system. The factory said no, it simply would not work, and the rest as they say is history. So the “myth” is indeed a fact that many dealers here still adhere to even today.

Prequalification procedures: What you are looking for is one of two conditions, the presence of quantities of ferrous particulates, or large amounts of alloy flakes. Ferrous materials are serious and probably an already dying IMS. Alloy flakes are always present in these engines, but usually is small amounts. When you start see them is large amounts, something is wrong, and installing an expensive IMS bearing that is open to oil lubrication is asking for a premature bearing failure due to debris ingestion.

Replacing the IMS with a low cost off the shelf all steel bearing every time you do the clutch: This idea sounds fine until you look at expected clutch life. We have customers that are still on their factory clutch at 200K miles, and a few at or over 300K. Like the Tiptronic cars, these would have never been retrofitted using your approach. But all of them were, and the original clutch was reinstalled either because it still looked fine, or the customer insisted on it.

Roller bearings: We do not install them for a multitude of reasons. They do not offer any significantly higher load carrying capacity than ceramic hybrid bearings, and some of the kits installation techniques are questionable at best. They also have a very limited performance history. As my shop’s reputation is on the line with every retrofit, we go with what we know has a proven record of over 25K installs with no issues. And quite plainly, they are not that much cheaper than the ceramic hybrids, and in any case the parts costs are only a small fraction of the total installed cost to the customer.

Returning defective parts: A nice idea, but what do you do when you send one back because its run out is too high, and the replacement you get is even worse? And you can only buy an assembled shaft with an oversized IMS bearing in it from the factory, at over $1K my cost, and to fully test the shaft you have to remove the factory bearing, which kills it. Jake has the luxury of having a pile of shafts to go through and select the good ones to put on the shelf for future engine builds. I do not have that luxury, we are always under time constraints to get the car back on the road ASAP.

CNC variations: How do you explain the issue if you can take one shaft out and put in one with little or no run out and the problem goes away? It may be the cases in some situations, but the shafts in the M96 engines decidedly have a problem all their own that is quickly solved by using a different shaft in the same cases.

IMS Solution costs: One Solution cost about as much as two ceramic hybrids, just for the parts. And with the exception of a small amount of additional labor to notch the bell housing to accept the oil line, the costs to do the Solution are exactly the same as the hybrid bearings. But the Solution is also a permanent life of the engine retrofit. So if an owner expects to keep the car for a bit, or sell it 60K miles down the road they would actually be ahead of the game when the first retrofit would have come up for subsequent replacement, and history has already shown that the Solution being permanent holds its value at resale while the hybrid is discounted for mileage since install. And to put an incorrect idea away, once and for all, you can install the Solution using the original tool kit, but will need the supplemental tool kit to install the IMS shaft plug behind the bearing on a Solution install. Most shops have the supplemental kit as it contains additional parts needed to do the later designed bearing, like the Single Row Pro. And many shops went to the Faultless tool as soon as it became available, simply because it makes any extraction or installation a quicker turn around, plus it eliminates any chance of a cocked single row installation, and is an absolute requirement for the Single Row Pro bearing. Using the Faultless tool, you shorten the time and reduce issues, which is every shops dream.

Sales of Solution installs also speak volumes; the demand for them has exceeded the supply nearly all of this year. Early this year, the wait time from order to delivery was exceeding 90 days. And we have more inquiries for the Solution than any other style retrofit bearing.

Ball bearings are more tolerant to run out than solid bearings: Jake’s experience is just the opposite. People seem to forget that, being an innovator, he relishes testing things to destruction to learn more. He has taken shafts with considerable run out that had factory steel bearings showing the telltale signs of shaft wobble and put a Solution in them and put them back in the engine. Then he ran the Hell out them and pulled them out for examination. While the solid bearing showed some polishing on the run out side, it was otherwise fine. If you have ever had the chance to hold an IMS Solution in your hand, and in particular the dual row version, the total contact area of continuously oiled surface is utterly immense when compared with the available contact patch of any type of ball or roller bearing. And because the solid bearing surface is both lubricated and cooled by twin oil ports and an annular oil channel, the Solution is a happy camper in situations that would be fatal to other types of bearings.

I have kept my Boxster what I consider long term (have had it for 15 yrs now), and have never bought into this need to preemptively change out the IMS or install an oil feed system. I don't drive it that much either (only put about 3-4K miles a year), and only change the oil every 2 yrs with Mobil 1 0w-40 (oil that most people here don't recommend). Whatever, the car runs awesome and has never failed me (have only had to replace a water pump, coolant tank, engine mount, a MAF, and brakes). It's still running. Amazing, huh? :) Just drive it and enjoy it.

/sign
could have been my post almost
Basically the same here...16 years old and max 5k km per year (obviously not my DD), service @ dealership every other year...nothing...nada...no repairs...nothing failed...it runs and runs and runs.
If the engine fails, it fails, there are other things to worry about in life ;)

ENJOY PORSCHE. Don't worry!:cheers:

Guys, that is just fine; it is your car and your money, and you are entitled to your opinion. None of what I posted here is designed to get anyone to change their behavior; it is just to clear up misunderstandings or misconstrued facts, nothing more.

Obviouly JFP has way more experience of these issues than any single owner. These are technical issues and wishing them away or denying them doesn't affect the defects.
The value of this thread and similar ones is to accumulate a list of actions to mitigate the risk, know the symptoms and causes and how to effectively fix them. Recommending the 'head in the sand' approach based on one personal anecdote is not technically adequate.

always welcome...

I gave up reading this thread as my technical understanding/background/experience is (sadly) limited for being a sales/marketing person by profession :cheers:

I guess it is sometimes, somehow beneficial not knowing everything :cheers:

Which is exactly what I did for a living before abandoning corporate life. It never hurts to learn.

I have no issues with the extra knowledge put out here either, but I kinda treat it like I do health info on the Internet... The more I read about things/ailments, the more I worry, so instead just try to enjoy and live my life as healthy as I can without obsessing about the little things that'll drive me crazy, and it works for me. So far, no IMS failure of my health. :)

Sure thing, that is exactly my credo, especially when getting older.

Sorry for not being able to contribute in this clash of paradigms, guys.
I just know my limits and know when to put my head in the sand :D

...and happy birthday to me, 400 posts