They are different. The new ones have holes in the disk to allow oil to flow out of the inner chamber of the lifter. As far as what exactly happened or, the story of the old lifters, I think there are things in life I'm not supposed to know like, how many licks it takes to get to the center of a Tootsie Pop. I was able to diagnose the lifters as being the issue and get it back to being happy and help an 80 year old family member enjoy his car again and that's ok by me. I have my thoughts on how this happened but, I may never really know for sure. Thanks for following along and, your input.