1988 318 engine

easiest way for the 'layman' to check how much stretch the timing chain has is pop the distributor cap off and rock the crankshaft back and forth on the damper bolt. the further it moves without the rotor moving in the dizzy then the more slack there is. you don't want much slack at all.
to be fair at that mileage it's worth fitting a new set as mentioned above, just to be safe.
neil.