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I've been following the IMS discussions and mostly keeping quiet and taking data as I'm the new guy here, and to paraphrase one individual, "you can learn an awful lot just by listening". I think that premature AOS failure due to DOF oil aeration may be over stated. Think of the state of oil at the rod bearings after it leaves rod bearing / crank journal interface. The reservation I have with DOF may be with my understanding of the system. After spending a few days perusing bearing manufacturing sites low speed bearings can be in an oil bath only partially submerging the lowest ball, or can have a DOF like system. High speed bearings use an oil mist system for longest life. Does the DOF squirt a stream of filtered oil or mist oil? I don't know, but I assume a stream. A stream of oil on the internal workings of the bearings would put an additional side load, a point load, on the moving internal bearing components that quite frankly, I've not seen quantified. Splash oil appears to be a non starter for 6204 steel bearings, but may be useful for the 6204 ceramic or larger steel bearings. Replacing the IMSB with a plain bearing is all about the plain bearing design. Is there enough real estate in the area around the IMS to float a plain bearing with the available oil pressure? Apparently so. If the sealed bearing could remain sealed retaining its grease, it would last the life of the other engine components (IMHO), or at least 90,000 mi in top gear.
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