I have an '82 Diesel that was sitting for nearly two years.  New fluids, new
battery and it started right up and ran rather well.  Put approximately 20
miles on it and got to the crest of a hill and heard a knock and lost power
(felt like a cylinder or two had gone).  I immediately put it in neutral and
pulled over.  It was still running relatively knock free.  As soon as I
stopped I shut it down.  Turned it over once and heard a knock.  That's it.
Had it towed to my mechanics garage.  I was wondering if anyone out there has
experienced this or something like it.  My guesses are a stuck valve (maybe)
or more likely a broken valve spring.  Assuming I didn't screw up the head, I
think it should be a relatively inexpensive fix, even if it needs all new
valves, springs, etc.  The engine had about 40,000 miles on it when parked.
Any ideas or wisdom is greatly appreciated.

Stefan - Wilmington, NC