BMW Repair: my 318 i s, cam chains, chain tensioner

Question
i have a 318 i s coupe and its started to rattle we took the head off and have noticed the cam chains are slack, is this a difficult job to fix and how shall i go about it?

Answer
Ian, If you took the head off and found the chain to be loose replace the chain, tensioner, and guides. I don't understand what is meant by 'how do you go about it'.
If you have the ability to remove the head then remove the balancer and timing cover and replace the components. By a repair manual like a Bentley or Chiltons. You already have the motor apart so it isn't that much more difficult. Replace the Cylinder head retaining bolts.
-Evan