Ah, the 2005 where you have no idea which bearing the engine has until you remove the transmission....

I am glad to see this discussion develop into technical dialog.

There seems to be 3 very different approaches to delivering oil to the IMSB. List in alphabetical order.
1. EPS (IMS Bearing Upgrade Kit) Cylindrical Roller bearing oil delivered through the oil pump shaft by modifying the shaft during installation.
2. Flat6/L&N, and Jake Raby (IMS Solution) Has removed the Bearing and oil delivered from spin on oil filter to IMSB flange through braided line.
3. Pedro’s (DOF) Roller bearing, from unused port in engine casing to IMSB flange through braided line.

I was very curious about the difference between Jake Raby’s and Pedro’s. Both deliver oil through braided line to the flange but from completely places. Last weekend I sent Jake an email asking why he choose his design as the DOF seemed a simpler way to get oil to the flange. He responded back rather quickly which was impressive. Here is his response to why do he pulls the oil from the filter.

I developed a system similar to the DOF many years ago, it never impressed me, and therefore it was not marketed.
That said, the oil that I collect for the IMS Solution is taken directly from the oil filter, it is JUST FILTERED OIL, and it has the highest volume, fastest priming, and highest pressure of any portion of the engine, because this post is the first orifice past the main engine oil pump. The DOF takes oil from where it does, because my first US Patent includes the Spin on Filter Adaptor method, so the DOF had to source oil elsewhere to reduce the infringement possibilities on this Patent.
United States Patent: 9416697

Review this here:
Layshaft end bearing retrofit with external positive oil pressure delivery
Single Document


That said, the reason I pick up oil where I do, is because I understand the fundamentals of this engine much more than the oil system diagram from Porsche. Pulling oil from the cylinder head is a way to see oil pressure which has already been reduced by the bypass system, and to collect unfiltered oil that has already passed dynamic components. This is NOT just filtered oil; therefore, it can present, and feed directly into the IMS Bearing, debris laden oil. Been there, done that years before anyone else had even extracted an IMS Bearing.

Two other supporting aspects for JFP's comments:
1.When this modified driveshaft was first introduced we voiced alarm at the deliberate weakening of an already weak part. Subsequently , it seems the depth of the groove in it has been reduced to the point where it is difficult to imagine any significant amount of oil can travel along the groove. So while you are in there, why not fit an upgraded drive shaft ?
2. The oil in the IMS tube. The premium IMSB replacement product has a plug to completely seal the tube. Why would they bother with this if it was not a problem ?
I am puzzled why the RND roller bearing product does not include this seal for the IMS tube.It would have been an easily added premium feature ?

I can agree with some of your point, but not entirely.

I have wondered if Porsche had originally sealed the end of the IMS as opposed to leaving it open might have made failing IMSBs a non-issue. But then that depends on what the majority mode of bearing failure is, rancid, acidic oil in the shaft eating at the bearing or simple failure due to stress.

But, the fact remains that the IM shaft does fill with oil on many/most cars and the oil has no means of escape, creating an oil flooded IMS. It seems to me that the EPS bearing being open allows the oil in the shaft to spin out past the bearing especially when subjected to centrifugal forces of a running engine, minimizing the amount of oil in the shaft while running. And new oil being metered through the pump shaft will provide continual lubrication for the bearing.

Regarding the oil drive shaft, I don't think it is a stock shaft with a groove cut in it. I looked, and they do not spell out how the shaft is manufactured. (which would be nice to see). But I am going to make the assumption that it has been engineered to account for the strength required in light of the groove. That is entirely an assumption. But then I have not read of any of these parts failing either.

I agree with you regarding the punch used to open a hole in the end of the IMS. It should be manufactured with a flange to prevent you from making the hole too big.

Now all of this is simply my understanding of the product and how it works. Many people here have vastly more knowledge than me regarding these engines.

But still, I pose the question: would their oil feed system and a standard un-sealed single row ball bearing be a viable option?

"would their oil feed system and a standard un-sealed single row ball bearing be a viable option?"
Probably should distinguish between single/double row ? If it is double, there is less incentive to go with any roller bearing kit?
Another option in this theme would be to use Pedro's DOF because his bearing is sealed on the inside and may minimize oil intrusion to the IMS tube. In theory you could use Pedro's DOF & the roller bearing? Ask Pedro. That may be attractive for cars originally fitted with a single row IMSB.

Two possible reasons:

1. The RND bearing may be open on the flywheel side to mist lubrication, much like the LN ceramic hybrid bearings, and therefore does not need the pressure lubrication.
2. Use of a plug in the rear of the IMS shaft may already be covered in a patent.

One thing you may be overlooking is that many, in fact most, IMS shafts do not run true. This means there is some inherent "wobble" in the factory shaft even when is dry. On engines that have suffered IMS failures at low mileage, the amount of this nonconcentric movement is often profound, and is believed to have played a role in the early demise of the IMS bearings as they were simply being beaten to death by the wobble in the shaft, as well as the loss of the grease. As I have mentioned on more than one occasion, we always find the shafts at least partially filled with oil when doing an IMS retrofit, and a common comment we get from car owners after we install an IMS Solution (with the shaft now dry and plugged behind the bearing area) is that the car now seems to run and idle smoother. As we have not changed the amount of inherent wobble in the shaft, but have removed any collected oil and prevented any new intrusion, those observation may be the direct result of there not being any oil inside the IMS shaft to exacerbate the existing wobble inherent to the shaft from the factory. We have also observed that some Porsche engine builders often drill small holes into the IMS shaft, specifically to allow collected oil to escape.

So if oil inside the shaft seems to be an issue with multiple solutions, why would you specifically introduce it in the first place?

Actually, introducing pressurized oil from the flywheel side has multiple potential issues. First, just how much oil is necessary? LN's history of more than 25K units successfully running on just the oil mist inside the engine say that not much is needed. Bearing engineers have chimed in to say that while some is good, a lot is not so good as it can induce "skidding" rather than rolling in the bearing balls, which they say is not a good thing. It is also common for shops to remove the rear seal from the third generation IMS bearings which cannot be easily retrofitted, and to my knowledge, there have been no reports of any of the oversized bearings run this way subsequently failing. Add in that it is well known that the factory bearings leak oil into the shaft behind the bearings without any induced pressure, pressurizing them is going to accelerate this process. Lastly, as Jake has already noted, where you source the pressurized oil from is critical; you want the oil to be clean and as cool as possible, while not short changing any other pressure lubricated components. With oil from the cylinder head being one of the hottest, as well as the dirtiest sources, and there have been multiple reports of both valve noise and VarioCam problems on engine's using the cylinder head oil to lube the IMS which promptly disappeared when the oil lines were plugged, you have to ask yourself if this is really someplace you want to go.

What I want to know is how someone like MarcW can get over 300k miles (and still going) on his 02 Boxster with original IMS. I thought it's not a matter of if, but when.

Think 'confirmation bias' when reading IMSB, oil or tire comments.

As others have said, the IMSB question has been beaten to death. Along the way, many have decided which option they prefer. Their comments and recommendations tend to reflect / justify those decisions.

Unfortunately, there aren't enough 'verifiable' facts available to tell the community whether one option is the clear winner. And even if such information were available, some would reject and argue against those findings because they run counter to already held beliefs.

Just so you know my confirmation bias...my 01S has the IMS Solution installed. It's been there for about 21 months. Why? I'd rather have a plain bearing than a roller or ball bearing ISMB. I could have opted for a lower cost option, but I don't worry about it anymore and that alone was worth the extra money.

For some it is, others not so much. We also have customers that have gone well over 200K with the factory bearings, and others have not made it to 50K. As with all production mechanical systems, some will go on nearly forever, but others will die prematurely for various reasons. But one inescapable is the Porsche's own data from the lawsuit: Of the single row engines produced between 2000 and 2006, approximately one in ten won't make it, and for the earlier dual rows the odds are somewhat better at 1-2% (no real hard numbers are known for the third generation bearings as they were not part of the legal action).

So it comes down to individual's risk tolerance levels; we have had customers trade in cars because of their concern, others have chosen to take preventative steps, and others simply decided to ignore it. All a mater of personal choices.

Thanks JFP. I guess my risk tolerance is pretty high. :) Mine's an 01 (produced in 2000), so I prob have the most risky version single row. :)

Wouldn't bet on that, we have seen many 2001's carrying the dual rows.

Good, so you're saying I have a chance! :D

Some related 2013-2014 posts that really stood out to me:

http://986forum.com/forums/performance-technical-chat/49448-another-ims-bearing-thread.html
-Introduces the roller bearing (Eternal Fix).
-Jamesp details his own solution.
-Jake Raby makes some significant comments.
-Who is 'Walter White' and what happened to him?

http://986forum.com/forums/boxster-parts-sale-wanted/54949-porsche-engines-sale.html
-Hidden in the Classified Ads section.
-Some strong opinions come out quickly.
-Somewhere among the flames there is some good contrast drawn between roller bearing and ball bearing solutions.
-Wayne elects to lock the thread before the riot police are called in.

thom7482,

You are correct. Out of the various products available people will tend to choose the one that fits in their schema. The was an interesting study I think from U of Kanas. The took people who felt capital punishment work and those that didn’t. Gave them research data that was contrary to their held belief. About 70% changed their belief with the new validated research. Then they were told the research was all made up and their original belief was correct and then asked how many wanted to go back to their original belief. I think it was only about 20%. The reality is we will never get true data on the efficacy of the virous IMSB options.

Do your research and each will find an option for them and hopefully be comfortable
with.

Thanks JFP. I am new to this forum and learned about the search.

So if you changed yours, what did you use? Also, age and miles on it. Thanks.

Let me be peacemaker ?
It is considered a discourtesy to the Forum to ask questions that have been very well covered in Search/Faq's.
It is best to ask a question in such a way that you demonstrate some effort at finding the answer or at least understand the history of the issue.
You will note that the more helpful/knowledgeable members drop out of these threads quickly. So if you are really interested in getting them to take the time to help you, try Search first.
If you don't you'll be mauled by the dogs ,as you may have noticed.
So I'll conclude with a specific pointer for you to answer the last question you posed: dear any Post by Mike Focke on the IMSB .Then you won't need to ask Mr.Particle or me anything .
I hope this helps you find the answer you need.

Thank you Gelbster. Appreciate it.