LN IMS Bearing Service Life

[Seadweller]

The IMS bearing in my '98 Boxster was preemptively replaced by the original owner in 2011 when the car had 27K miles on it. The car now has around 37K miles on it, and in looking at the LN Engineering recommended service intervals, they indicate 6 years or 75,000 miles.

I'm clearly beyond the recommended 6 year service interval, but well below the mileage interval. I'm having trouble understanding why there's a time interval. Do the ceramic balls deteriorate with age? Is there any reason that the bearing should be replaced again?

[JFP in PA]

Why not call LN and ask them............................

[PaulE]

I can tell you that my LN Single Row Pro lasted about 35,000 miles. That model is a dual row ceramic bearing that was a direct replacement for the single row OEM bearing in my 2003 S. I bought my car new and at around 42,000 miles I thought it would be a good idea to preemptively upgrade my IMSB. The LN unit failed at 77,500 miles. I don't think it is a matter of the ceramic bearings failing, I think it is a matter of some small bits of debris in the oil finding their way into the bearing, and then the harder ceramic bearings grinding that debris into the softer steel bearing races until they let go. Of course there shouldn't be any debris in oil but something happened. My rebuilt engine has the LN IMS Solution. My uneducated guess is that 10,000 miles should be ok regardless of time if you are changing the oil frequently, but JFP said it best, give LN a call, they were very helpful to me when my IMSB went and that is why I went with the IMS Solution for round 2.

[tonythetiger]

@PaulE, what was the impact to your engine? Metal making it to the bearing sounds like another issue, but how was it resolved? Curious minds.



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[PaulE]

Originally Posted by tonythetiger

@PaulE, what was the impact to your engine? Metal making it to the bearing sounds like another issue, but how was it resolved? Curious minds.



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I had driven about 500 miles from my home in New Jersey to Le Circuit Mt. Tremblant in Canada for a PCA HPDE. My region does tech inspection the night before the start of the event so I drove over to the track from the hotel and cleared tech and then drove back to the hotel. On the way back to the hotel the engine felt a little weird/I remember thinking it must have been tired from the long drive. The next morning on startup it sounded like a washing machine running without water and full of rocks, so I shut it down and parked it. One of the owners of the independent Porsche shop that does all the work on my car and one of their technicians were at the HPDE, they came over to the hotel to take a look at my car, and upon starting up the car again they said shut it down. I was lucky to get a tow home from another club member and he took my car to my shop and I drove his 997 GT3 that he trailered up for the trip back.

My shop performed a leakdown test which came out good and dropped the oil pan which didn't have much metal in it so I let them tear down my engine to look further. The only parts damaged were the IMSB, the IMS, a timing chain paddle on the rear of the engine was broken in two, parts of my oil pump and a couple of bent valves. The bores looked really good but I decided that as long as I was this far into it I might as well make my engine a 3.6 so they sent it to LN for Nickies and my engine is now as listed in my tagline below. The engine failure happened in early July 2018, and getting the LN Nickies done took about 6 months so I finally got my car back in March 2019.

I was lucky it happened as it did. If it had happened somewhere on the long trip up I would have been driving along at highway speeds and the failure would likely have caused a lot more damage.

[tonythetiger]

Great story and I guess the best outcome you could have hoped for, given circumstances.


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[Seadweller]

Originally Posted by JFP in PA

Why not call LN and ask them............................

I did reach out, but have not heard back. I'll update when they respond.