Toyota Repair: 1991 22-RE Timing Chain, water jacket, timing chain

Question
I have a 1991 Pickup 22-RE 2WD with a 5-speed stick. I've been told the timing chain needs replacing, and I'm pretty sure it does. But it only has 87,000 miles which seems really low to need the timing chain. It makes the noise on startup and goes away after a few seconds. My question is, how much more life can I get out of the current chain without causing any damage to engine or components? Also, what should eventually be replaced with the chain itself?

Answer
These engines had a tendency to break the chain guides which is probably the cause of the noise, there is a chance eventually that the chain will wear through the water jacket inside the timing cover and cause coolant to enter into the engine oil which can cause a major problem, the solution is to replace the chain, tensioner and gears as soon as possible.