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The IMS discussion thread (Read this first!)

 
Old 02-26-2019, 12:04 AM
  #406  
911Syncro
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Thank you Charles. One thing we should be able to conclude: periodically reving the Tip to higher RPMs won't help much as a preventative measure..
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Old 03-25-2019, 12:05 PM
  #407  
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took my newly acquired 2003 c4s (22k miles) into dealer for IMS replacement. maybe it would never fail, but for the cost vs peace of mind i'll take peace of mind.
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Old 04-13-2019, 05:50 PM
  #408  
angello
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Default One more IMSB failure thinking....

Hi guys , regards from Croatia.
I have an early 2005 997.1 C2 tip with 108k kilometers ( 67k miles) on it. This is a M96/05 engine and the engine number (69501175) says it has the single row ims bearing . The car is great , all services done in Porsche service but their oil change intervals were naturally at 20k kilometers (12000miles) , Mobil1new life 0w40. So I am a bit worry about the imsb failure. I have done only 4k kilometers in two years but I have changed the oil recently. The engine/ gearbox is dry , no unusual noises , no debris in the oil filter. I have learned all about the imsb issue , all about retrofits , LN , Pedros DOF , EPS , etc. The problem is Croatia is a small country, low number of 996/997 Porsches and not a one imsb failure at all ! So my Porsche mechanic says they are not trained and he will not do any retrofit with some parts out of the oem porsche parts. This is a tiptronic gearbox so there wont be any clutch changing in the future.It is not a low mileage car so I am giving up on any ims solutions by now.
Anyhow , by reading and learning about imsb failure , we all presume it happens at about 8% of the cars with single row bearing , low mileage cars , garage queens , short driving with not properly heated oil , low revs , long oil change intervals ....etc.
All of these facts have made me thinking about what could be in common of every all the above mentioned suspections ? The only thing I can find is the oil level in the sump. I can not find any post about it on any Porsche forum . Let me share my thoughts with you:
The ims bearing was a sealed ball bearing with grease in it when was new. After some time and mileage the engine oil enter the bearing through the seals and wash the grease out. That is a fact because all the owners who has as precaution measure changed the bearings say there was no grease inside but there was engine oil. And most of the bearings were good.
Therefore , the bearing was lubricated with the oil , no problems. The oil level in the sump comes at about 1 or 2 centimeters from the lowest part of this bearing when the engine is not running so the bearing is partialy in the oil when the car is in the garage. When we start the engine , the bearing picks up the oil and spins lubricated . Whats the oil level in the sump when the engine idle and what is on higher revs , I dont know because the oil must get to every part of the engine. This is technically a dry sump engine so there is no oil splashing around by the crankshaft so I dont know how much oil the bearing gets at this point. But I believe when we stop at the lights and the engine idle , the bearing is again partialy in the oil. I am talking about the fresh and clean oil changed regularly. Also there is some amount of oil in the shaft, good or bad depends on some other facts. But the bearing is lubricated.
Now, we are talking about the garage queens , low mileage cars with the old engine oil inside. Do these owners check the oil level when they seat in their cars ? I dont think so. Even if they check it , they assume all is ok as long as the oil level is not at the minimum on the scale on the display. And the difference from the minimum and maximum oil level could be more then 1 liter ( quart ) ! What is going on with the bearing now when the oil level is too low ? Does it seat dry for months , and doesnt get initial oil splash?? How much oil does it get when the engine idle or revs? I dont now but I think this is the issue with these 8% or 1% on the other two kinds of berings . Apart from that , I think low revs and cold oil doesnt go through the bearings seals to refresh the old oil stucked in the shaft as well.
What do you think about it ?
pardon my english....
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Old 04-16-2019, 07:58 AM
  #409  
Charles Navarro
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Originally Posted by angello View Post
Hi guys , regards from Croatia.
I have an early 2005 997.1 C2 tip with 108k kilometers ( 67k miles) on it. This is a M96/05 engine and the engine number (69501175) says it has the single row ims bearing . The car is great , all services done in Porsche service but their oil change intervals were naturally at 20k kilometers (12000miles) , Mobil1new life 0w40. So I am a bit worry about the imsb failure. I have done only 4k kilometers in two years but I have changed the oil recently. The engine/ gearbox is dry , no unusual noises , no debris in the oil filter. I have learned all about the imsb issue , all about retrofits , LN , Pedros DOF , EPS , etc. The problem is Croatia is a small country, low number of 996/997 Porsches and not a one imsb failure at all ! So my Porsche mechanic says they are not trained and he will not do any retrofit with some parts out of the oem porsche parts. This is a tiptronic gearbox so there wont be any clutch changing in the future.It is not a low mileage car so I am giving up on any ims solutions by now.
Anyhow , by reading and learning about imsb failure , we all presume it happens at about 8% of the cars with single row bearing , low mileage cars , garage queens , short driving with not properly heated oil , low revs , long oil change intervals ....etc.
All of these facts have made me thinking about what could be in common of every all the above mentioned suspections ? The only thing I can find is the oil level in the sump. I can not find any post about it on any Porsche forum . Let me share my thoughts with you:
The ims bearing was a sealed ball bearing with grease in it when was new. After some time and mileage the engine oil enter the bearing through the seals and wash the grease out. That is a fact because all the owners who has as precaution measure changed the bearings say there was no grease inside but there was engine oil. And most of the bearings were good.
Therefore , the bearing was lubricated with the oil , no problems. The oil level in the sump comes at about 1 or 2 centimeters from the lowest part of this bearing when the engine is not running so the bearing is partialy in the oil when the car is in the garage. When we start the engine , the bearing picks up the oil and spins lubricated . Whats the oil level in the sump when the engine idle and what is on higher revs , I dont know because the oil must get to every part of the engine. This is technically a dry sump engine so there is no oil splashing around by the crankshaft so I dont know how much oil the bearing gets at this point. But I believe when we stop at the lights and the engine idle , the bearing is again partialy in the oil. I am talking about the fresh and clean oil changed regularly. Also there is some amount of oil in the shaft, good or bad depends on some other facts. But the bearing is lubricated.
Now, we are talking about the garage queens , low mileage cars with the old engine oil inside. Do these owners check the oil level when they seat in their cars ? I dont think so. Even if they check it , they assume all is ok as long as the oil level is not at the minimum on the scale on the display. And the difference from the minimum and maximum oil level could be more then 1 liter ( quart ) ! What is going on with the bearing now when the oil level is too low ? Does it seat dry for months , and doesnt get initial oil splash?? How much oil does it get when the engine idle or revs? I dont now but I think this is the issue with these 8% or 1% on the other two kinds of berings . Apart from that , I think low revs and cold oil doesnt go through the bearings seals to refresh the old oil stucked in the shaft as well.
What do you think about it ?
pardon my english....
It's a common misconception that the M96/M97 engine is a dry sump engine. It is indeed a wet sump engine and there is a lot of oil being thrown about the inside the engine by the chains as they pass through the engine oil.

The original seals on the bearing are designed only for intermittent use at 250F, which over time, become hard and brittle, failing to keep the grease in the bearing. Based off many years of observations, most IMS bearings will have their grease washed out and the shaft itself will fill up with oil, even with the seals still present. This oil, along with the partial submersion, will provide some oil to the original bearing.

If the primary cause for bearing failure was solely lubrication, we would expect the original dual row and later MY06-08 bearings to fail at equal rates to the least durable single row.

Once a bearing has been fitted without a grease seal (open bearing), there is ample oil mist from oil laden air along with the partial submersion to ensure proper lubrication for your choice of ball or roller bearing.

With regards to your mechanic only using OEM Porsche parts, currently the only option is a teardown and installation of the current MY06-08 complete IMS shaft. The "Retrofit" bearing kit released by Porsche with a sealed, single row ceramic hybrid bearing was available for ordering only for a very short period in 2017 and soon became unavailable for ordering.
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Old 04-16-2019, 01:22 PM
  #410  
angello
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Charles , the M96 3.6 engine is technically a dry sump engine but with the oil tank in the engine. It has a scavenge pump , oil splash protection plates and crankshaft counterweights dont swim in the oil when the engine is not running. But this is not so important.
My question is what happens with imsb when it seats for a longer period dry , over the oil level with the owners who let their cars with oil level at minimum ? We agree the original grease has been washed out after some mileage.
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Old 04-17-2019, 08:41 AM
  #411  
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I had the Solution installed in October in my new to me 2003. I was at 45000 miles. Bearing seemed fine. No real idea how to tell. I removed the seal. There was no sign of any grease or lube. It didn’t even look like there was ever grease in there.
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Old 04-17-2019, 11:26 AM
  #412  
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I suppose there was oil inside the bearing , wasn' it ?
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