I've told this before, but I had a tensioner failure on my first 911, many moons ago (before the days of the internet and great resources like this BBS!!). I didn't even know what a chain tensioner
was back then. It made one heck of a racket ( imagine a bag of assorted nuts and bolts banging around inside your motor - that's the noise!) and there was no doubt
something was wrong. So I just drove it slowly, back to my house and then 10-15 miles to my mechanic the next day. Miraculously, there was no damage at all, other than the tensioner itself!
-- Curt