Thanks for the reply, I was beginning to lose hope. I've been voraciously reading posts and for all the information on W126 timing chains there is almost nothing on crankshaft sprockets. Its nice to have a second opinion.
I think I'll leave this one to the pros, I was feeling pretty confident about trying the chain and guides but pulling the whole front cover seems like a whole new level of difficulty.
I'll stick to chassis repairs and tune ups for now.
1988 420SEL 170K