I am guessing but I think what JFP wisely means is that if there is any metal missing from the IMSB - it is 'toast'. In which case I agree. Perhaps I misunderstood the 'smearing' description of the race and thought that no metal had separated ?
I had a similar issue and just dismantled the entire engine ,repaired/rebuilt it and we'll see how long it lasts....I was lucky that the collateral damage was minimal.

Okay, but how about the plug
 

The bearing had come apart and the filter was production based, so yes, I'm sure metal is everywhere, thus, its toast. But the question was, "is removing the plug to investigate the interior of the shaft a good idea?" Clearly, it would only be a good idea if the bearing failure is caught before becoming catastrophic (no reason to investigate further if rebuild is inevitable), even then however, only if the plug is "serviceable", i.e. a replacement is readily available. Is it?

Even if a failure progresses to stage 3 (bearing stays intact, just tons of debris) the engine is toast. You'll never remove all the debris, and no oil filter is good enough to catch enough of it at those quantities.

If it has gone that far, please use a competitors product, and when it fails make sure that you are very vocal about the fact that their part blew up!

Here is a parts diagram -tell us which part number you are calling a "plug".
M96.20 Camshaft M96.21/22 Driving Mechanism M96.23/24
or:
http://www.pelicanparts.com/techarticles/Boxster_Tech/14-ENGINE-Intermediate_Shaft_Bearing/images_small/Pic019.jpg
Reluctantly I did what Jake asked. Mine had an LN ceramic IMSB that had less than 1000 miles on it when #6 c/s bearing was damaged.No fault of the LN part.

Some people say "the debris was really small, its not a problem".

well, let me tell you, if you think that, you'll learn fast. the smaller the debris the WORSE it is! The heavy stuff sits at the bottom of the sump, it doesn't splash all around inside the engine as it is suspended in the oil.

I'll take chunks any day over the small, fine stuff, thats microscopic in size.

If the bearing begins to fail, unless its caught at Stage 2, or prior, take the whole damn engine apart. Do it now.

Thanks for the parts diagram, but I do not see the "plug" in the diagram, nor is it included in the Pelican's parts photo. Attached are a few photos of the plug I pulled. The photos show what you would see if you were inside the intermediate shaft looking out towards the shaft bearing. You are seeing the back of the "plug" which is pressed inside a steel sleeve, which is pressed into the bearing end of the shaft before the bearing, thus "sealing" the hollow shaft from the bearing.

Now, most of the destruction on the other end was caused by my welding a nut to the sleeve to use a slide hammer puller to get the plug out of the shaft.
http://986forum.com/forums/uploads01/0011446820776.jpg
http://986forum.com/forums/uploads01/0021446820826.jpg
http://986forum.com/forums/uploads01/0031446820958.jpg

That plug isn't from the factory. The center portion appears to be a metric expansion plug.

Factory IMS shafts are not plugged, which is why we have to supply a specially manufactured plug with the IMS Solution.

Xcell,
Aren't you glad I asked about the plug a.k.a. Freeze plug?
Looks like an 'interesting' previous diy job. How much damage has been done to the IMS tube? Reuseable?
If you need a replacement plug,try here:
Freeze Plug Size Chart « freezeplugfactory.com

Thank you
 

Thanks, Jake and Gelbster for staying with me long enough to figure out what this was. I appreciate the information.

It now appears to me that this failure is just what Jake has warned against. On this car it appears that the original IMSB failed and during replacement, the plug was installed. We don't know what caused the second bearing to fail, but it wasn't because of rancid oil in the shaft, the plug did it job there. So we can only guess that the second bearing most likely failed from debris left behind from the first failure.

Now the question becomes, should we all be using a plug when replacing an IMSB that hasn't failed as a preventive measure?

Thanks again,
Live, read, and learn,
Joe

Posts like #109 are very helpful and need to be cited in future when we read of people just slapping in a replacement IMSB and flipping the car.
There are lots of draconian directives and pre failure directives published by some vendors.Now we have an example(perhaps) of why they are so insistent of specific conditions before they will warranty an IMSB replacement .
Pre-failure Directives
My car failed less than 1000 miles after an IMSB replacement by the P.O..
The freeze plug :
what if you distort the thin-wall IMS tube during insertion? Pin it & bearing+Loctite sufficient?
what if it becomes loose
Drill a small vent hole in it?
Which type of freeze plug and why? Many different types in the link I posted #108 .Cup style in s/s ,I presume?
Here is some Melling info on deep cups:
http://www.melling.com/Portals/0/Size%20Charts/Expansion%20Plug%20Dimensional%20Listing.pdf

The freeze plug is not a standard size to my knowledge, which is probably why Jake has his made for him. We took one we had on hand (cup style) and turned it down on a lathe. I do not remember the dimensions off hand, but if you have a shaft lying around you can "mike" it and figure what would be needed for an interference fit without ballooning the shaft. If memory serves, we used Loctite 37485 slip fit bearing mount adhesive to lock it in place and seal it.

Drilling a hole in it would be counter productive to sealing off the shaft from oil intrusion.

@ Gelbster:

As we know there can go a lot wrong when installing or deinstalling a roller bearing.

Plug: http://986forum.com/forums/472269-post57.html I definetly go with a machined tube style made of a soft aluminium alloy, because it can't twist and will expand more to seal. Also a soft metal won't hurt the IMS tube.

No holes. You'll have overpressure in the IMS tube. The tube was designed for that, because of the sealed OEM bearing.

Regards
Markus

JFP,
Very helpful,thank you.Your experience is more valuable than my pontificating :-)
"Drilling a hole in it would be counter productive to sealing off the shaft from oil intrusion."
I was trying to address the concern expressed earlier about pressure changes in the IMS tube. AS Markus says, maybe no longer a concern.
There are brass freeze plugs listed below- easier to modify than steel.
http://freezeplugfactory.com/expansion-plug-size-chart/

The pressure inside the IMS shaft is irrelevant if it is sealed and has no oil in it.

The ONLY reason the bye is sealed with the IMS Solution is because we've seen IMS shaft assemblies loose their press fit, and simply fall apart (MOF#24).

The assembly is made of 4 pieces, if oil pressure, and volume (under pressure)can enter the tube, the possibility exists that a hydraulic event may occur that could assist in the shaft separating.

Plugging the IMS tube eliminates this, as no hydraulic pressure exists within the shaft, and if a shaft disconnects, its simply bad luck.

Now, the technology that uses the IMS tube to transfer oil (via pressure) into the bearing has the possibility of catalyzing this issue, under the right conditions.

The decision to plug the IMS Shaft for the IMS Solution took me 3 years to finally decide on. I ran many engines both ways, and NEVER had an issue. In the end, plugging the shaft was the best possible way to go. Why? Because the IMS shaft has a volume of 2/3 of 1 quart of oil. If the shaft is not plugged, as the engine operates the active oil level drops, and if the oil is checked within a few minutes it always shows low. When this occurs, someone adds oil, and then the next morning the engine is overfilled by 1/2 qt, as the IMS tube has drained back to the sump slowly overnight.

Yes, now you see why I never sleep.

Ha! It's all about addressing the potential "what if's" isn't it?

They never end....

This has turned into such an interesting thread,I learned so much from this already!
So if I fit the retrofit, do you also suggest I plug the ims shaft or will it be ok with an open shaft? Will the engine be starved of oil when the shaft fills with oil?

Unless you are using the IMS Solution, then no plug is required with any other LN Engineering product. Why? Because the bearing has an inner seal that does a great job of keeping ANYTHING out of the IMS tube. Oil, air, gases (insert laughter here) or even smoke, after the engine explodes!

I have extracted many classic single, dual and Single Row Pro LN IMSR bearings and to date oil has NEVER been found inside the tube of an engine fitted with these. Not once, not ever, and that takes into consideration the removal of the very first IMSR bearing at least two dozen times to check it during development.

The IMS Solution is a different story, as it's journal bearing delivered oil into the shaft, and fills it within seconds after start up of the engine, if the plug is not in place.

In short, follow the directives of the manufacturer of what you are using. Don't try to out smart them, as its the quickest way to shoot yourself in the foot. of course, that only pertains to truly developed products, not those that are cobbled together in someone's garage.

Oh, so if I'm understanding correctly the bearing is only open from the flange side,and it has a seal on the shaft side. So that also eliminates the acidic oil that gets accumulated in the shaft with the original bearing,right?