IMS bearing inspection

[pothole]

Originally Posted by thom4782

I'm at 100K with my '01S. My IMSB shows no sign that its near the ends of its working life. My clutch has seen a lot of miles, but isn't slipping yet or making noises. While I don't what to spend the $2,200 US to replace these parts, I plan to do so in the next few months for two reasons.

First, I plan to keep the car for another 10 years so longevity is important to me. Second, and most important, I've owned my car for 10 years. I know how it's been maintained and what has been repaired. So I'd prefer to stay with a car I know intimately than either spend a lot of time looking for a well documented alternative or go with an unknown.

So that's my risk calculus. I'm willing to spend the $800 US extra to install the LN bearing when replacing the clutch because that's a small price to pay when amortized over 5 to 10 years or when avoiding buying an older car with a unknown history. And that's really the heart of my risk profile.

BTW: if you visit the following site, you'll see some data on LN bearing failures: dual row = 0% and single row = 0.1%. IMS 101 | IMS Retrofit. See third paragraph from the bottom.

As today has worn on, I am beginning to come round to this way of thinking.

I know my car well, it already has plenty of newish parts on it (water pump, rads, coils etc).

But I do find the admission that some of the single-row retrofit bearings have failed pretty worrying. What has caused them to fail? I thought the point of the hallowed LN bearing design removes the known failure modes.

Obviously no mechanical part is perfect. But to me "about half a dozen" sounds like a fair few failures for an aftermarket part that can take the engine with it when it goes.

I also find it hard to believe the 99.9% thing if they have had six failures. That means they are claiming to have at least 6,000 single row bearings running in the field. That sounds like far too many to me.

[thom4782]

I'll add couple more thoughts to the discussion and stop.

A well respected Porsche dealer in my area installs the LN bearing as its preventive maintenance measure and not the Porsche bearing. That's saying something.

At least LN has put numbers on the table which Porsche apparently hasn't done.

I'll take LN's 0.1% over Porsche guesstimated 2% to 5% any day of the week.

[pothole]

Originally Posted by thom4782

A well respected Porsche dealer in my area installs the LN bearing as its preventive maintenance measure and not the Porsche bearing. That's saying something.

At least LN has put numbers on the table which Porsche apparently hasn't done.

Honestly, I'm not sure it does. It's not like we fully understand either exactly why some factory bearings fail and others don't or if the LN design is unquestionably advantageous and / or if it has its own issues.

To my mind, we have very little proven data. All we know for sure is that the factory bearing definitely fails. I'd say the jury is still out on the LN kit to at least some degree.

And I'm not totally sure LN has put numbers on the table when its numbers are apparently saying it has sold 6,000 single-row bearings, which seems implausible to me.

On a related note, i have to say that IMS Guardian thing strikes as pretty preposterous. Obviously that a whole separate topic. But the IMS subject is tricky and the lack of hard data has a tendency to have people making assumptions that may not be true.