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-   Boxster General Discussions (http://986forum.com/forums/boxster-general-discussions/)
-   -   IMS question. (http://986forum.com/forums/boxster-general-discussions/19729-ims-question.html)

j.fro 03-15-2009 07:31 AM

I just finished watching Charles' video...thanks so much for posting that. It was one of the scariest movies I've seen in a long time! Those bearings remind me of the bearings in coaster-brake bicycle hubs. ugh

Blue-S 03-15-2009 10:24 AM

Quote:

Originally Posted by Jake Raby
There is no other bearing opposite the failure prone IMS bearing.

There is no bearing insert in the case, the bearing just rides against a machined portion of the case and is lubricated hydrostatically... The cams ride in the heads without bearing inserts as well.. Much like a 36HP VW engine or a 356 engine- No cam bearing inserts.

Well, that's a surprise! Now I am left wondering why Porsche designed the engine with a pressure lubricated bearing surface at one end of the IMS, but a sealed bearing at the other end. I know that the use of the aluminum case and head surface as bearing area is very common -- most overhead cam cylinder heads are built this way -- but the use of a sealed bearing inside an engine is highly unusual. I have seen sealed bearings used successfully inside transmissions, but in that application the bearing does not have to cope with fuel and water laden engine oil attacking the seals.

Jake Raby 03-15-2009 03:31 PM

One of the fixes we had planned for the IMS originally was to make the roller bearing end of the shaft also supported by a plain bearing thats hydrostatically lubricated and we may still try this.. But our current fixes are working great and the key is now to reduce the loads the IMS sees...

Look for much more information being shared soon, including more videos that describe the engine internals.

litteng 03-15-2009 04:20 PM

bearings cages again?
 
Those blasted bearing cages... one of the biggest headaches with the bmw single sided swingarm R1100/1150 motorcycles has been cage failures and then the differential large bearing piles up,

this should be something that wants to be checked anytime you have the gearbox off for clutch service etc.

thanks for being so kind to show us whats going on,

Charles & Jake; the metal flaking from the bearing ball and races, does any of it show up in UOAnalysis, i would suspect that at the least we sould be able to find it in the filter ?


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