Replacing IMS with Original bearing

[Bala]

Originally Posted by mikefocke

The LN IMSR had a total of 3000+ installs as of late last year according to Charles. That of course includes both 986s and 996s. Failed bearings returned to Charles are sent to Ed for analysis.

Aren't we lucky to see so many P-car owners working together to come up with the best solutions they can for us.

JFP said about 4-5 failures. Out of 3000? That is good.

You are right about the owners working together. This collective effort and support is what makes owning this car fun and possible. Without this collective effort (and the members of this forum) I wouldn't touch this car with a 10 foot pole.

[berty987]

I think the big question here is whether it's better to rely on the seals of the original bearing to keep the grease in and contaminants out , or a ceramic bearing relying on clean oil to keep it lubricated.

[Bala]

Originally Posted by berty987

I think the big question here is whether it's better to rely on the seals of the original bearing to keep the grease in and contaminants out , or a ceramic bearing relying on clean oil to keep it lubricated.

That's a gamble as well isn't it? Considering that ferrous bits can come from other sources and affect the LN bearing which is not sealed.

Wonder if the magnetic drain plug might actually help in drawing and keeping the bits confined in one area and away from the bearing to some extent.

[spongebob]

Originally Posted by berty987

I think the big question here is whether it's better to rely on the seals of the original bearing to keep the grease in and contaminants out , or a ceramic bearing relying on clean oil to keep it lubricated.

A bearing filled with grease does always have a specific limited lifetime compared to bearings that are lubricated by oil. Guess that Porsche knows the lifetime here but this is of course only possible to calculate if the grease is kept inside the bearing.
However , original intention must have been a lifetime well beyond 200,000km

In Mr Rabys solution lifetime will probably be very good as long as there is no loose debris entering the bearing which cant be guaranteed. Just look inside your oilfilter every oilchange.

I guess that no double row bearing with the grease kept in place has failed yet.
The single row bearing was probably some kind of costcutting project as the IMS failures where uncommon the first years and there was room for lower spec of the bearing.

When it is time for my next clutch I will,( if they exist) use a standard bearing but with upgraded seal spec and grease that can take more than 120 degrees C.
This will be done in combination with a low temp thermostat and 10/40W oil

Until then I will feel very safe with the IMS guardian.

[Bala]

One thing I don't understand (or not educated on) is why am I finding the metal pieces at the bottom - oil pan. These should have gone thru the filter and actually should be in the filter no? Don't think those pieces just came loose when I turned off the car and then proceeded to drain the oil and removed the pan.

Just tried feelyx's suggestion and used a magnet. NONE of the pieces stick. There are also some tiny pieces black in color. Plastic maybe?

So, if the LN bearing is not sealed and is lubricated by oil, and the contaminants (metal) can come from elsewhere, there is a high probability that it can damage that bearing as well. So, a sealed one is much better bet not considering lubrication factor? Your take on an upgraded seal bearing makes a lot of sense to me. Of course the IMSG would allow just in time intervention if a disaster was going to happen in all cases. But, no such bearing exists does it. Can a OEM bearing be purchased, upgraded lubrication and upgraded seal be made to order?

[berty987]

Reading up on bearing failures it's normally a result of the race guide or the balls suffering damage. Typically this damage is caused by either foreign particles entering the bearing races or the bearing race/balls fragmenting as a result of excessive heat from running at too high a speed /load or with insufficient lubrication. The advantage of ceramic or composite materials is they are less affected by temperature or foreign particles. Assuming Porshe specced the bearing correctly for speed and temperature the only realistic cause of failure is that the lubrication is washed away or that foreign particles enter the bearing causing deterioration. Either way, there is a very strong case for fitting a bearing that can operate with less lubrication or oil lubrication rather than grease and that is more resilient to foreign particles in the race guides.

A question for Jake and flat six innovations at this point. With full ceramic bearings available , why is the solution offered using a hybrid rather than full ceramic ? Is there an issue with full ceramic bearings in terms of load or shock resistance that is required in this application ?
For instance the bearing listed below meets the temp requirements for the application
6204 Full Ceramic Bearing 20x47x14 Ball Bearings

Or the full compliment Silicon nitride bearing
6204 Full Complement Ceramic Bearing 20x47x14 Si3N4 Ball Bearings

I assume the bearing offered currently is something like this ?
6204-2RS Hybrid Ceramic Sealed Bearing 20x47x14 Ball Bearings
SKF - Product data

[bosbruce]

Originally Posted by Bala

JFP said about 4-5 failures. Out of 3000? That is good.

You are right about the owners working together. This collective effort and support is what makes owning this car fun and possible. Without this collective effort (and the members of this forum) I wouldn't touch this car with a 10 foot pole.

5 failures out of 3000 with how many years/miles on them? If most have under 2 years and under 10k miles, I'd like to know how many OEM failures we had with such low hours/miles... Might be an even lower percentage?

Given all the talk of how driving habits and oil change intervals effects OEM IMS, I'd also suspect there MUST be a difference between manual and auto trannys and between 2.5 and 3.2 L engines, and would LOVE to hear some statistics on that.

It is great to read all the information on these forums about IMSR and IMSG, but I just keep coming back to the basic fact that we have pretty much only hearsay on percentages of various vehicles OEM failures.

Given that, my plan is to go with IMSG in hopes it might give me warning for any number of possible engine issues, and maybe do IMSR when there is more data of LN replacement failure rates over time and when I have to replace a clutch or fix that tiny oil drip from the RMS (about 1 drip every 2 months)...

Cheers,

Bruce (2000 Boxster S 6MT, 22k miles)

[JFP in PA]

Originally Posted by bosbruce

5 failures out of 3000 with how many years/miles on them? If most have under 2 years and under 10k miles, I'd like to know how many OEM failures we had with such low hours/miles... Might be an even lower percentage?

Most of the handful of LN units that had issues were not installed properly; to my knowledge, only one suffered a true failure...........

[mikefocke]

The LN kit was first available March of 2009. When last I checked, 4,000+ had been sold but that was several months ago.