After reading a post here about a pair of 420's losing their guide rails, I believe its time (96k miles) to replace mine.

Along with the chain and rails, what other moving parts should be replaced?

There is also some clatter noise coming from the valve covers. Can the "lifters" be adjusted or are they solid?.

Is Camshaft wear a concern?
Jim

The tensioner (116 050 18 11) and the cam oiler line repair kits (116 180 01 84)x 2