Improperly selected cam core materials... SADI cores are not intended for the spring pressures and beating that the MDS can deliver. I'm willing to bet that the 6.4s and all of the SRT offerings use billet cam cores like they should have, and that's the MAIN reason why you don't see those failures on those engines.
I think burla's fix, while it may have some positive results, is putting the cart before the horse. I'm no lubrication engineer but the higher viscosity likely provides more of an impact cushioning effect than the hot 20 weights, along with keeping the oil out of the "increased wear zone" as was discussed in some of the other oil threads. When you get an extremely thin film of oil, and then beat the snot out of it, the temperature will rise quickly. Then, the 20 weight oils lose their "normal" lubricating properties as the localized oil temps skyrocket; you start to ride hardened lifter roller directly on much softer, austempered ductile iron cam lobes, and well, even those who failed chemistry and metallurgy classes can come to the same conclusions that the engines do.
You wipe a cam lobe and spread chunks of ductile iron through the pan and then wipe out lifters too.
I think burla's fix, while it may have some positive results, is putting the cart before the horse. I'm no lubrication engineer but the higher viscosity likely provides more of an impact cushioning effect than the hot 20 weights, along with keeping the oil out of the "increased wear zone" as was discussed in some of the other oil threads. When you get an extremely thin film of oil, and then beat the snot out of it, the temperature will rise quickly. Then, the 20 weight oils lose their "normal" lubricating properties as the localized oil temps skyrocket; you start to ride hardened lifter roller directly on much softer, austempered ductile iron cam lobes, and well, even those who failed chemistry and metallurgy classes can come to the same conclusions that the engines do.
You wipe a cam lobe and spread chunks of ductile iron through the pan and then wipe out lifters too.