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Message: [QUOTE="TooManyToys, post: 1521474, member: 30841"] Guys, this isn't my normal forum so please excuse my jumping in. I've been curious about this as well and over the past weeks have been trying to research as much as I can. I only have my one motor 6.0 experience but have been looking at as many cam and lifter issues online as I can. BTW, my Ford reman motor is apart but did not have the cam/lifter failure often seen. Never buy a Ford reman ...... I've been trying to look at this from an engineers perspective and there are a good number of papers including those presented within SAE. The preponderance of work is done on the roller cam surface, in some cases stress injury during the grinding process, but other issues related to oil viscosity and debris in the oil. Much of the work revolves around the high pressure of two wheels (lobe and lifter roller) noted under the term Hertzian Contact Stress and when you do the calcs the pressures are very high. Some of the discussion is around the elastic deformation within the two contact points (you can see that by the change in the residual tracking marks) and how over time that can lead to the sub-surface fracturing of the lobe. Throw some debris between the contact point and the loading goes logarithmic under the debris. We see that as pits or brinelling on the ramps or nose of the lobes. Any pitting or brinelling leads to a loss of lubricating film and the stress just gets higher, the stress cracks widen and you can eventually just beat the crap out of the wheel, bearings, and axle of the lifter. Between the Powerstroke motors, the 7.3L has half the Hertzian contact loading compared to the 6.0L and 6.4L due to the number of valves. So it can be a lifter issue, but I think it can be a cam issue too. If it is a cyclic fatigue failure, which would be based on cam revolutions, it would occur at the same point with high idle hours, low mileage trucks as with long mileage low idle trucks. It would all depend when/how you get to the revolutions. Anyway, I'm just throwing that out here but won't drive you insane as I've done elsewhere, I think it's an interesting discussion. Some info and an image of one of my cam's lobe surface, again no failure, just 75k miles highway. it shows scuffing from the wheel sliding on the opening ramp and the other surface issues. While ramp scuffing is present on all my lobes, the pits or brinelling is all at the last four lobes, cylinders 7 and 8. Edit- sorry, not familiar with adding images into this forum. [ATTACH]50386._xfImport[/ATTACH] [/QUOTE]