Walked 7bolt 2.4 Results

[Raptor]

The interesting thing about the way the bearing was worn was that it was more on the outer diameter than inner (closer to crank journal) the reason that is could be from a number of things, but I have my own theory on it. As you said the thrust surface relies on a very thin layer of oil which would keep the bearings suface separated from the crank surface. That can only happen if both surfaces are perfectly square with each other. If one surface is able to flex even .001" the surface would no longer be square and the oil would have an exit path as well as a higher point to sheer the oil from. If that were to happen even in a small amount, the contact created wears the crank then the surface is rough and oil sheer is pretty much guaranteed. When installing the crank, you put pressure on the flywheel end of the crank to align the thrust bearings before the cap is torqued to make sure there is a flat surface as well as making sure the thrust surface that recieves the most load is up against the main web so it has support to keep it from flexing. That is all fine in a normal environment where there isn't excessive pressure beyond what the engineers had in mind for the engine and size/strength of the bearings. With the increase in load, on the bearing surface, the only way to compensate would be to use stronger/harder materials to prevent any possible flex or wear. That is why the h rated bearings make sense. Also having the crank nitrided if the surfaces are soft makes sense.

All the "definitive" answers everyone comes up with havn't exactly been proven without question so I have to go on the observations I make and what I believe makes sense from others experience. I believe H rated bearings, a nitrided crank and lighter pressure plate force will solve the issues.