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alex yates Le Mans


Joined: 06 Mar 2014 Posts: 15227 Location: The Ribble Valley, Lancashire
2000 Porsche 996 Carrera 4
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bakerboy4s Monza

Joined: 06 Jun 2015 Posts: 229 Location: Staffordshire
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Posted: Fri Jan 25, 2019 1:21 pm Post subject:
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Hi Alex
No doubt LN will point out the quantity sold versus quantity failed, it would be interesting to know if the percentage failure of retro fitted ims is similar to original ims failure!
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wasz Sepang
Joined: 28 Dec 2012 Posts: 2789
1999 Porsche 996 Carrera 2
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Posted: Fri Jan 25, 2019 1:41 pm Post subject:
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bakerboy4s wrote: | Hi Alex
No doubt LN will point out the quantity sold versus quantity failed, it would be interesting to know if the percentage failure of retro fitted ims is similar to original ims failure! |
An educated guess would say the failure rate of retro fits should be higher than factory due to the risk of damage during install. Will the bearing go in straight? what are you pressing against at the other end to get the bearing in? etc etc.
No need to replace a perfectly functioning bearing really. Inspect it for sure, but I wonder if bore score is more common nowadays than IMS bearing failure. _________________ My special order MY99 Vesuvious Charcoal 996 | Clutch, Fly RMS IMS AOS Job |
Steering Rack Hard Lines | Air Con Compressor / System
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alex yates Le Mans


Joined: 06 Mar 2014 Posts: 15227 Location: The Ribble Valley, Lancashire
2000 Porsche 996 Carrera 4
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Posted: Fri Jan 25, 2019 4:18 pm Post subject:
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About 50% _________________ 2000 Manual 996 C4 Arctic Silver Convertible
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bakerboy4s Monza

Joined: 06 Jun 2015 Posts: 229 Location: Staffordshire
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Posted: Fri Jan 25, 2019 4:45 pm Post subject:
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wasz wrote: | bakerboy4s wrote: | Hi Alex
No doubt LN will point out the quantity sold versus quantity failed, it would be interesting to know if the percentage failure of retro fitted ims is similar to original ims failure! |
An educated guess would say the failure rate of retro fits should be higher than factory due to the risk of damage during install. Will the bearing go in straight? what are you pressing against at the other end to get the bearing in? etc etc.
No need to replace a perfectly functioning bearing really. Inspect it for sure, but I wonder if bore score is more common nowadays than IMS bearing failure. |
I guess the general consensus now is inspect bearing, removal of seal and if a new bearing is required a strip down of the engine and replace the offending article is the way to go, but do you replace with a ball race, roller bearings or the non bearing LM version?
I'm not looking to open another long tirade of posts just a quick survey from the engineers among us.
Hopefully it'll be along time until I have to make the decision!
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alex yates Le Mans


Joined: 06 Mar 2014 Posts: 15227 Location: The Ribble Valley, Lancashire
2000 Porsche 996 Carrera 4
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Posted: Fri Jan 25, 2019 4:50 pm Post subject:
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One of them there £30 washing machine bearings infrasilver fits in his. _________________ 2000 Manual 996 C4 Arctic Silver Convertible
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Magic919 Österreich
Joined: 05 Jun 2013 Posts: 971 Location: Berkshire
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Posted: Fri Jan 25, 2019 5:19 pm Post subject:
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LN Engineering were quite clear about their failure rate when we put one in a 996 some years ago. It wasn’t a fit for life fix by any means. _________________ 997.2 C2S PDK
997.2 C4S PDK
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infrasilver Fast & Furious


Joined: 04 Oct 2010 Posts: 8070 Location: East Midlands
2001 Porsche 996 Targa
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Posted: Fri Jan 25, 2019 5:31 pm Post subject:
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alex yates wrote: | One of them there £30 washing machine bearings infrasilver fits in his. |
Mine is actually a Hartech washing machine (same spec) bearing. _________________ http://euroroadtripper.blogspot.co.uk/
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infrasilver Fast & Furious


Joined: 04 Oct 2010 Posts: 8070 Location: East Midlands
2001 Porsche 996 Targa
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Posted: Fri Jan 25, 2019 5:32 pm Post subject:
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Magic919 wrote: | LN Engineering were quite clear about their failure rate when we put one in a 996 some years ago. It wasn’t a fit for life fix by any means. |
They actually denied for years saying it was installation errors but then had to admit it was no better or worse than a standard bearing but only when the lawyer's came a knocking. _________________ http://euroroadtripper.blogspot.co.uk/
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Robertb Long Beach

Joined: 01 Sep 2003 Posts: 6769 Location: South Oxfordshire
2002 Porsche 996 Carrera 4S
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Posted: Fri Jan 25, 2019 6:30 pm Post subject:
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My own thinking is that the failure rate of original bearings was say 5%.
Over time, the % gets smaller on a Darwinian basis as the ones that were faulty have failed.
If you replace a perfectly good bearing that’s survived this long you are increasing, not decreasing the chance of failure.
The only genuine improvement that I can see is the modded 997 bearing. _________________ "911- the guilt-free supercar"
Current: 2003 C4S Coupe, seal/black
Ex: '02 C4S Coupe, '96 993 Targa, '88 Carrera Sport Coupe
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Chris_in_the_UK Estoril

Joined: 19 Mar 2014 Posts: 3542 Location: Harrogate
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Posted: Fri Jan 25, 2019 8:50 pm Post subject:
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infrasilver wrote: | Magic919 wrote: | LN Engineering were quite clear about their failure rate when we put one in a 996 some years ago. It wasn’t a fit for life fix by any means. |
They actually denied for years saying it was installation errors but then had to admit it was no better or worse than a standard bearing but only when the lawyer's came a knocking. |
Indeed - always been a 'snake oil' item. _________________ 2006 Cayman S PCCB's
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kas750 Reims

Joined: 31 Mar 2013 Posts: 4279 Location: Chorley lancashire
2006 Porsche 911
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Posted: Fri Jan 25, 2019 8:58 pm Post subject:
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Robertb wrote: | My own thinking is that the failure rate of original bearings was say 5%.
Over time, the % gets smaller on a Darwinian basis as the ones that were faulty have failed.
If you replace a perfectly good bearing that’s survived this long you are increasing, not decreasing the chance of failure.
The only genuine improvement that I can see is the modded 997 bearing. |
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deMort Zolder

Joined: 21 Mar 2015 Posts: 5937 Location: Brighton
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Posted: Fri Jan 25, 2019 9:22 pm Post subject:
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This is one of those do i or dont i answer topics ..
You are all aware of what i do and What i do Here .
Garage checks said bearing and says there is no play and its fine .. customer wants it replaced , hes read the forums these things go bang and he wants a new one .
It doesnt matter how many times i tell him the bearing is fine he wants a new one .
Garages are here to provide a service , we advise the customer but if he wants a new bearing being which ever make we do what is asked of us .
Now and then we find a shagged bearing .. excessive play .. we give the customer the option , fit an aftermarket bearing at say £1200 or do the proper repair .. circa £6k .. its pretty obvious what they choose .. we can argue the benifits but if the customer cant afford it then its irrelevant .
i do know the ealy LN bearing problems were down to the fitting process which has now been modified .. well .. its been explained to me shall we say .
I Dont know if these are a long term fix .. none we have fitted have ever come back .. LN offeres a warrenty .. not sure if its good for anything as we have never had a problem ... is there a choice that customers can afford though .
At the end of the day .. if your bearing has play then something needs to be done and cost is the factor on what you have done .
Customers decides .
Forums are a mine of information but they also cause issues like this ,
My opinion anyways .
EDIT ... we dont fit very many per year .. perhaps 3 _________________ .
My Daughter's Crowdfunding page Here
7pm - 9pm
Now At An Indy.
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alex yates Le Mans


Joined: 06 Mar 2014 Posts: 15227 Location: The Ribble Valley, Lancashire
2000 Porsche 996 Carrera 4
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Posted: Fri Jan 25, 2019 10:35 pm Post subject:
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kas750 wrote: | Robertb wrote: | My own thinking is that the failure rate of original bearings was say 5%.
Over time, the % gets smaller on a Darwinian basis as the ones that were faulty have failed.
If you replace a perfectly good bearing that’s survived this long you are increasing, not decreasing the chance of failure.
The only genuine improvement that I can see is the modded 997 bearing. |
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Infant Mortality. If this graph had a scale, the letter 'e' of Time would be around 100k miles
 _________________ 2000 Manual 996 C4 Arctic Silver Convertible
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Chris_in_the_UK Estoril

Joined: 19 Mar 2014 Posts: 3542 Location: Harrogate
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Posted: Fri Jan 25, 2019 10:39 pm Post subject:
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The engineer in me still maintains this is (was) the wrong solution (type of bearing) for what is a low % issue.
I respect why professionals in the Porsche repair business may take a neutral view - particularly as it might affect customer perception and money through the door. The internet has some influence and lots of folk have next to no mechanical savvy (lot on here seem to have, thankfully). _________________ 2006 Cayman S PCCB's
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mid Newbie
Joined: 28 Nov 2017 Posts: 9 Location: Northampton
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Posted: Mon Jan 28, 2019 1:51 pm Post subject:
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so here's my dilema - my brother has had his 996 about 3 years, was spooked by all the internet stories and had the LN ceramic fitted to his car within the first week of ownership....he was running at about 95K at the time but the car had seen little use over the previous few years.
on inspection he made a good choice as the removed original was almost seized solid! so he was happy...
fast forward 18 months or so and about 2K miles (if that) and BANG! engine self destructs in a BIG way... but it wasn't the IMS causing the failure.
in the meantime, i've bought myself a 100K mile 996 still running the original bearing...
i have the LN out of his old engine (removed with the proper tools etc) and it seems perfect. LN insist that it should never be reinstalled after removal and i need to buy a new one.
so do i fit it?
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wasz Sepang
Joined: 28 Dec 2012 Posts: 2789
1999 Porsche 996 Carrera 2
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Posted: Mon Jan 28, 2019 2:19 pm Post subject:
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mid wrote: | so do i fit it? |
Noooo. Next time you need a clutch I would inspect the bearing. If its silky smooth with no play as it probably is, flip the seal off and stitch it all back up.
mid wrote: | fast forward 18 months or so and about 2K miles (if that) and BANG! engine self destructs in a BIG way... but it wasn't the IMS causing the failure. |
This just proves it. You could do all that unnecessary work and still something else will fail. Its a 100k 15 year old engine, lots of things wear out / age.
You might damage the old one on removal, damage it or something else on the way in, or be out of line on reassembly.
You'd be even more miffed if the replacement bearing failed....
I've never ever heard of anyone using second hand press fit cartridge bearings in any application, they are single use surely.
If it will help you sleep at night put a new bearing in! Doesn't have to be an overpriced one.
But ooooh what about your main bearings won't they be worn at that mileage? Bores starting to score? Or your vary cam pads? chains stretched much? May as well rebuild and be completely at ease.
If it were me - full rebuild now and future proofing, or inspect and enjoy it till it dies. It might never happen (in your ownership). _________________ My special order MY99 Vesuvious Charcoal 996 | Clutch, Fly RMS IMS AOS Job |
Steering Rack Hard Lines | Air Con Compressor / System
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kas750 Reims

Joined: 31 Mar 2013 Posts: 4279 Location: Chorley lancashire
2006 Porsche 911
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Posted: Mon Jan 28, 2019 3:13 pm Post subject:
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mid wrote: | so here's my dilema - my brother has had his 996 about 3 years, was spooked by all the internet stories and had the LN ceramic fitted to his car within the first week of ownership....he was running at about 95K at the time but the car had seen little use over the previous few years.
on inspection he made a good choice as the removed original was almost seized solid! so he was happy...
fast forward 18 months or so and about 2K miles (if that) and BANG! engine self destructs in a BIG way... but it wasn't the IMS causing the failure.
in the meantime, i've bought myself a 100K mile 996 still running the original bearing...
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Equally it could of been collateral damage caused by the replacement that instigated the failure I.E damaged chains/tensioners.
What part failed?
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deMort Zolder

Joined: 21 Mar 2015 Posts: 5937 Location: Brighton
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Posted: Mon Jan 28, 2019 7:47 pm Post subject:
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mid wrote: |
i have the LN out of his old engine (removed with the proper tools etc) and it seems perfect. LN insist that it should never be reinstalled after removal and i need to buy a new one.
so do i fit it? |
Never ever in a million years use it .. and i fit these things from new !!! _________________ .
My Daughter's Crowdfunding page Here
7pm - 9pm
Now At An Indy.
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mid Newbie
Joined: 28 Nov 2017 Posts: 9 Location: Northampton
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Posted: Tue Jan 29, 2019 3:25 pm Post subject:
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Quote: | Equally it could of been collateral damage caused by the replacement that instigated the failure I.E damaged chains/tensioners.
What part failed? |
we're not actually 100% sure what was the primary cause... my theory is that one piston siezed... i think a ring slipped. this was the only piston that didnt contact valves. the resultant mess makes it difficult to pinpoint any one particular area!
re the LN ims.... i'd pretty much talked myself into leaving alone - and enjoying it until if or when it goes bang... i've always planned on mine being a keeper so even if i park it up for a while and work on it myself its not a problem.
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