Hemi 5.7 & 6.4 engines can experience cam damage from lifters that have the “wheel” or roller freeze and stop turning. When this happens the roller then begins to skid along instead of rolling. In seconds it begins to dig into the camshaft, cutting into the lobe and ruining it. In the business, the slang term for this damage is called a “wiped lobe”.
Once this happens you need LOTS of expensive work done to fix the problem correctly. Timely oil and filter changes and proper care go a long ways toward preventing this kind of damage. The cam above shows just the kind of damage that is done when this type of failure occurs. It’s ugly, sounds terrible when it happens, and is very upsetting when it’s your vehicle that just wiped a lobe. This isn’t one of those things where you ask “my Hemi makes some noise , do you think this might be what happened to mine?”
If this is your problem, you KNOW you have a problem for sure LOL. If you are facing this issue and you have high miles I suggest a full rebuild, and this would be an excellent time to consider getting a set of NON MDS lifters and performing an MDS DELETE while you’re at it to eliminate quite a few other potential future problems, and to make your Hemi as close to bullet proof as possible!