"Uncle Tony" is a walking encyclopedia on old-school HEMI engines... but, his summation of the GEN III HEMI lubrication process (related to lifter and cam damage) may be incorrect. Since lifter/cam damage is not seen on every Gen III HEMI engine, flagging the Gen III HEMI as a flawed design is unwarranted. When there is damage, it's generally limited to only one lifter/lobe. Why? This may explain what's happening... HOT ROD ON MDS: A few things can happen that can cause this mechanism to break down, the most common of which is oil contamination. When small pieces of dirt block the lube circuit, the lifter may not be able to change state, or the change may happen slower, or only partially. A common scenario with the MDS system in Hemis is where the ECM believes the lifter is engaged at higher rpm when it is not. Here, the internal pin that locks the lifter body to the plunger is still disengaged when the engine rpm goes up. In this failure mode, the roller follows the cam lobe, until it reaches an engine speed where it can't, and the roller crashes repeatedly on the lobe. Eventually, the lifter, roller, needle bearings, and the lobe surface become damaged to the point of failure. Engine oil age needs to be calculated via total engine revolutions, not mileage. A dedicated meter would simplify this, of course. Maybe we can get MOPAR to add one.
From what I've read (out of concern that the failure could be inevitable for all at some point, should I get rid of my car) it seems more prolific in the trucks. I've gone to great trouble and expense (long story) to turn off MDS (hate it anyway) hoping it may also have preventative impact. What's your impression re how wide spread this failure is etc.? Seems the timing chain recall has been effective.
