Im also wondering why this is being done..

I have 57k miles, yes I hear the chain but
I always have and it sounds the same

 

Here are some pictures. Had 59,000 miles when I did the replacement. Hard to say if or when it would become an issue. For me it was to remove a potential issue.

 

What's your opinion Luis? That does not look bad to me. Then again I dont know how much it has changed from original spec. Are you thinking that divot was flush?

 

They look untouched to me based on some of the other timing components changes seen on this site.

 

Anyone have a photo of a new tensioner, old style without the stainless reinforcement.

 

Interesting. It was always my understanding that the original tensioner guides are flush.

If they are flush then I think there are two concerns.
1, that the tensioner May get stuck in the hole.
2, that the hole will continue to grow and could cause chain slack as reported.

It would be very interesting to see a failed engine due to timing issue to see how significant the tensioner rail erosion was. I think that would be the only way to determine.