Quote:
Originally Posted by southernstar
PS Truly enjoyed this 'debate' but, as Jake Raby points out in a parallel thread, it may ultimately be incapable of resolution.
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I disagree.
Two things are known. Ceramic bearings are better than steel because they are stronger, Unsealing these ceramic bearings is better than keeping them sealed because this eliminates the compromised lubricant problem that occurs when engine oil mixes with the internal grease lubricant. What is unknown here is whether DOF extends the operating lifetimes of unsealed ceramic bearings substantially longer so that is worth taking the risk to change the dynamics of the engine lubricating system.
To date, there is the track record of thousands of unsealed splash oil lubricated ceramic bearings which shows no dual row failures and a handful of unconfirmed single row failures. The DOF developers imply that this record results primarily from the fact that these retrofitted bearings are ceramic. They contend that splash oil is inadequate; it will lead to additional premature failures and DOF lubricated bearings will last longer by comparison. They don't say how much longer.
Whether DOF actually extends the operating lifetimes of retrofitted unsealed ceramic IMS bearings without incurring other engine problems will be known when when DOF cars attain comparable levels of retrofitted bearing use. For the 986 community, unfortunately, building that record for DOF will take years.