First off, you need to establish whether the ticking is from the injectors of tappets (hydraulic cam followers).
TBH, the injector 'tick' is only audible with yer bonce under the bonnet, and even then, it's pretty quiet.
On the other hand, a tappet or even worn camshaft etc will click occasionally, then all the time, then clatter like crazy!
I did a top-end rebuild on an old 8v engine a couple of weeks back - it was seriously bad with really ridged cam lobes. It's now sweater than most engines over 2 years' old!
Look for scratches on the cam lobes and the followers underneath them. Of course, if u do find a ridged camshaft, it's a bit of a mare to do as the bolts securing the cam housing, also clamp the head to the block, unless you have the special tool of course!
Really, an 82k engine which has had regular oil should be ok but u never know.