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I have my engine completely dis-assembled due to an IMS bearing failure at 120K. I'm replacing any obviously worn parts. Those that still have service life will not be replaced, only cleaned and inspected. I had to buy a used IMS shaft and bearing on E-bay as the current dealer part has a larger unservicable bearing I did not want. The used IMS bearing that came along with the shaft I bought has clear signs of engine oil infiltrating the grease (very bad). So to the IMS bearing. I've been researching the IMS bearing for about a week now in my spare time and have come to the following. As you have a 2004, you and I likely both have the same stock IMS bearing - its an NSK 6204DU17 deep roller ball bearing. Its a single row bearing. I admit I've a bit to learn as I'd have coded the bearing as a "DDU" as it has two seals and I've not decoded the 17 yet (A little help anyone?). Could be a Porsche specific designation. This is a greased bearing that is running in an oil environment. I have a post on IMS failure in the "technical" section on this site with a youtube link that shows why I think these bearings fail. It is a lubrication problem, and unfortunately, it always will be. I believe I have a method to slow that down by venting the IMS tube (see the vid for an explanation) but that is not a complete fix AND the engine has to be split to do it. Sooner or later the IMS bearing will lose lube and fail. It is fair to assume every IMS bearing is losing its greased lube due to normal engine operation every time the engine has an on/off cycle. So on to the IMS Solution. It is a "plain bearing". This is the simplest, and perhaps most robust bearing design. It is used on the other end of the IMS shaft, which does not fail. The same concept is also used on your crankshaft and camshafts. You should contact Jake Raby to answer any specific questions on this as it is his design. If I had not decided to perform a budget rebuild (a challenge to myself) on this engine, with my own IMS bearing fix (another challenge), I would seriously considered the IMS Solution over all other options. I think it is fair game for you to ask Jake questions on how this was designed and tested, and why it is an appropriate design for the driven end of the IMS shaft (hint- different loading than the other end). Those are my thoughts. Oh yeah, and I'm still figuring out the no holds barred engine I'll build as a replacement to the one I'm learning on now. Whatever you do, I advise you change out the original bearing, cut it open, and post what you find to this forum. My bet is that it is currently full of oil, not grease.
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