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JFP in PA · 02-10-2022, 11:49 AM

A couple of responses:

3) The seal facing the flywheel tends to harden and shrink over time, allowing oil to enter the bearing and wash out the grease. We have seen many bearings, dual and single rows, where the grease was gone, but relatively little oil was in the shaft. We have also seen both with totally flooded shafts, which may be a function of heating and cooling pulling the oil in, but as several of the non-flooded shaft bearings showed considerable degradation, it is the grease getting washed out and poor lubrication that leads to bearing failures.

5) The oil level only normally reaches the bearing level when the engine is not running; people fail to realize how far down the sump level drops with the engine running, particularly if it is running hard. Porsche put oil scavenging pumps in the cylinder heads for a reason: To get the excess oil trapped in the heads back down to the sump to keep the sump oil pump pickup covered. We actually tested this idea many years ago during an engine dyno test by drilling the case on a track car engine and installing barbed fittings with a clear hose in between them so we could see the oil level at various RPM levels. The oil level drops almost immediately after the engine starts and drops way more when the RPM levels go up. Even under modest engine speeds, the oil level is below the IMS bearing, so removing the rear seal allows oil mist in, not liquid oil.

6)2000 and 2001 engines would be either single or dual row IMS bearings. These years are considered a "transitional period" for the bearing designs, requiring pull the flywheel and looking to determine which bearing is in the engine. In spite of all the drivel posted on the internet, build dates on these years are useless; I personally own both a very early 2000 M96 engine car, and one of the very last produced in 2001, both purchased new during the model year. When I retrofitted both with IMS Solutions, I found the 2000 engine was a single row, while the 2001 was a dual row, which is totally contrary to what the internet thinks should be there.

02-10-2022, 11:49 AM	#8
JFP in PA Registered User Join Date: Feb 2005 Location: It's a kind of magic..... Posts: 6,273	A couple of responses: 3) The seal facing the flywheel tends to harden and shrink over time, allowing oil to enter the bearing and wash out the grease. We have seen many bearings, dual and single rows, where the grease was gone, but relatively little oil was in the shaft. We have also seen both with totally flooded shafts, which may be a function of heating and cooling pulling the oil in, but as several of the non-flooded shaft bearings showed considerable degradation, it is the grease getting washed out and poor lubrication that leads to bearing failures. 5) The oil level only normally reaches the bearing level when the engine is not running; people fail to realize how far down the sump level drops with the engine running, particularly if it is running hard. Porsche put oil scavenging pumps in the cylinder heads for a reason: To get the excess oil trapped in the heads back down to the sump to keep the sump oil pump pickup covered. We actually tested this idea many years ago during an engine dyno test by drilling the case on a track car engine and installing barbed fittings with a clear hose in between them so we could see the oil level at various RPM levels. The oil level drops almost immediately after the engine starts and drops way more when the RPM levels go up. Even under modest engine speeds, the oil level is below the IMS bearing, so removing the rear seal allows oil mist in, not liquid oil. 6)2000 and 2001 engines would be either single or dual row IMS bearings. These years are considered a "transitional period" for the bearing designs, requiring pull the flywheel and looking to determine which bearing is in the engine. In spite of all the drivel posted on the internet, build dates on these years are useless; I personally own both a very early 2000 M96 engine car, and one of the very last produced in 2001, both purchased new during the model year. When I retrofitted both with IMS Solutions, I found the 2000 engine was a single row, while the 2001 was a dual row, which is totally contrary to what the internet thinks should be there. __________________ “Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein Last edited by JFP in PA; 02-10-2022 at 11:52 AM.