808Bill

Now the real question, why did the PO change the bearing and why is the new bearing failing at less than it's intended lifespan?

JTT

Yes, looking like that was a very good investment!! Clearly works based on all the checks around the engine showing no debris. Big thanks Jake and LN!!

With the lack of debris anywhere I could find, how crazy would it be to replace the bearing and do a few flush oil changes and monitor for debris? Pushing luck?

JTT

I was told the prior owner changed the bearing as a preventative measure. I have no evidence that this is or isn't accurate, as he had the car a couple of years, but only put very low mileage on it. Bearing was changed prior to sale, along with clutch and a couple of other small items identified in another potential buyer's PPI. Could have been the installation process, prior debris, material failure/defect, the tech might have dropped it on floor while putting it in damaging it, or it could have been fairies for all I know. I don't believe in blaming anything or anyone without evidence to support it. No conspiracy theories please, and no product bashing. I will see if LN wants the bearing back for assessment, but I don't blame them.

JTT

Double post, sorry

808Bill

I was thinking more in the lines of shaft and bore trueness from the factory. But all those other things you mention could play a part in it all I guess...

Porschetech3

Well with this information we can assume a couple of different things.

One is that the PO changed the IMSB AFTER finding debris in his motor. And we would have to conclude that the engine ran 22k without wearing any other parts (except the LN ceramic bearing) as oil analysis is still clean and engine shows no other symptoms, no debris in sump, oil pumps look good, only debris caught in filter from ANOTHER IMSB failure.

Option 2 would be that the PO DID change the IMSB preventatively, and that the bearing just failed for whatever reason.

Chris(MA)

If he installed it badly and put some kind of shock or load on the inner shaft during installation this will cause impressions of the ***** in the races, setting them up to be doomed sooner rather than later.

Porschetech3

What did you decide to do with this? put in a new bearing, do a few oil change flushes, and roll the dice?

Or do a rebuild?

JTT

Porschetech3

I think that is a wise choice.I have the same scenario and have chosen the same remedy. I have 3 Porsche's , a 99 Coupe a 99 Cab and an 02 986 with a "S" engine.

The 99 Cab I just discovered yesterday had a little ferrous metal in the filter. I DO have a non-bypass filter on it !! I have only had the 99 Cab for about a year and have done 4 oil changes on it before every track day. Last track day was in November and no debris in the oil filter. It has not even been driven since. I was getting it ready for another track day when I saw the debris, very light and ferrous. Removed the transmission and flywheel and IMS bearing and it still has the original Dual Row with the seal still in tact, but there is looseness and roughness on the OUTER ROW , the inner row still seems smooth. The engine only has 70k on it and has had a hard life, even before I got it and I haven't let up on it.but to those who think the dual rows don't fail, never let your guard down !! I caught this very early, just as you did, and have a non-bypass filter, so I'm pretty sure the engine will be fine.

The clutch disc was worn down about to the wear limit and I already had a Kevlar clutch disc and pressure plate waiting to go in, (flywheel is in great shape) so this will all work out nicely. Plus my second gear was a little hard to engage when cold, and I already had a 2nd gear synco to install ( only minimal disassembly since 2nd is near the rear of the gearbox). So I'm killing quite a few birds with this stone.

JTT

JTT

It's been a while, so I thought I would update this thread. I changed the IMS bearing with a new IMS Pro. Replaced RMS as well. Bolted it all back. First oil change after 15 mins of run time on stands. Filter and oil clean. I've got about 350kms on the car now and have replaced and inspected filters three times now, all with clean results (well, two bits of sealant from sump plate). Looking good so far.

In reflection, besides gratefulness for the LN zero bypass filter adaptor, I was wondering if maybe a failure of a ceramic bearing like mine, might give a bit more breathing room. With the ***** being so hard, the race clearly is what started to fail. I can't help but think, a steel ball bearing might have strewn more debris, as it would have been shedding not only from the race, but also the bearing? I wonder if if played a role in detecting failure before total devastation?

Chris(MA)

Its a fair point you make, on a regular bearing the two surfaces destroy each other, making it faster and more severe. With the ceramic ***** being so hard the race takes the beating but the ***** keep their shape much more than a steel ball would; hence the failure is slower and gives you more time. It probably saved your engine.

Have you installed bearings before? installing them correctly is really very important.

spud72

^^ It's so important, I'd go so far to say that I suspect a lot of premature failures for aftermarket bearings are likely due to improper installation. Just my .02 from watching "technicians" work on bearings my past 25 years in the industry.

I'm also not convinced in the slightest about the benefits of ceramic bearings for this application.

JTT

Yes, in fact I used the LN Faultless tool, which pretty much makes it foolproof. I left the mallet on the bench I do agree, that improper installation is a very likely issue in many failures, particularly with aftermarket installations not done at factory.