Porsche discloses frequency of IMSB failures.

[oc-boxster]

What exactly is the difference between a single and double row bearing? What makes a double row better than a single row?

[NoGaBiker]

Originally Posted by oc-boxster

What exactly is the difference between a single and double row bearing? What makes a double row better than a single row?

Twice as many rows.

[1olddude]

Is there any hard statistics to prove the LN bearing is any less prone to random failure than OEM? Have they been around long enough to really have an educated opinion or do we need more time? I assume my 02 S with 13,000 miles on the odometer is a single row and in the group more likely to fail - (low miles and single row = double whammy). I hate the thought of tearing into a mostly new motor and then wonder what other potential problems that can cause down the road, but I may do it anyway. I really don't worry about it too much anymore and I just enjoy the ride.

[Nimbus117]

From what I have read, most failures were in low mileage cars (<30k). If it were my car, I would definitely get it replaced.

I share your thoughts on the LN bearing, it hasn't been around long enough to know if this is a permanent fix.

[Perfectlap]

Originally Posted by 1olddude

Is there any hard statistics to prove the LN bearing is any less prone to random failure than OEM? Have they been around long enough to really have an educated opinion or do we need more time?

Well LNE is a privately owned company so they are not required to disclose their stats anymore than Porsche never did. But LNE have posted many times on various Porsche forums that they've sold well over 10,000 retrofit bearings with only a handful going down to defeat and those few were mostly due to improper installation or failures on engines that were already compromised -- owner must have heard something funny and tried to make amends too late.
They also state that they've not had a single LNE dual row bearing go down. Given that this is not an easy DIY, I think professional insallation would keep the numbers of correctly installed LNE bearings pretty high.
My own mechanic told me he's done about 400 at his is small shop where they're not rushing cars in and out.

The other thing too is that these forums are pretty hard to control if you're selling snake oil. If lots of folks were having their LNE bearings go down you'd be hearing about it pretty quickly. I can't recall reading about a single one on 986forum, Renntech or Rennlist. But I have read about dozens of factory IMS failures.
Granted the size of water-cooled Porsche owners who post on these forums is a fraction of the total.

[WhipE350]

My 2000 'S' had a mint condition double row in it when I took it out at 55k miles. Of course now I have an even sweeter LNE double row installed and never ever think about it.

Side note, my new 981 likes to run around in long gear 7th all the time in the 1400 to 2400rpm unless I'm having fun which is most of the time so far. Sure glad the bearing is gone now!

[mikefocke]

Are their LN installation failures? Yes.

Are there a very very few unexplained LN failures that can't be attributed to installation or collateral damage? One or two out of perhaps 10k by now.

Are there a few LN bearings that have been taken out by the failure of another unconnected part failing and spewing metal through the engine that gets caught up in the LN bearing which is lubed with unfiltered oil? Yes, a few. (Why "The Solution" uses just filtered oil. And why all IMS failures aren't really caused by the IMS itself failing.)

Total for all causes around 1/10 of 1 % for LN last I checked versus 1% per car per year (my guestimate) for the OEM part (includes ones known to have failed and ones seen failing on removal).

So for the LN there are now thousands which have been driven several years, some over 50k miles. I think we are seeing some data that LN willingly shares to see the materials and lubrication method LN chose, while not perfect, are much better than the ones used in the cars from the factory. (Can you afford perfect?)

And LN recommends an inspection or replacement every 50k miles just to be safe.