Make sure you are rotating the engine in the normal direction of rotation (clockwise when facing the engine from the front!) -- the fan blades will give you a clue, too.
If not, you have pulled all the "slop" in the chain out of the short side and the number will be way off -- at 28 degrees, you bend valves!
Also make sure the tensioner rail is tight -- it's the one on the right side below the cam. You can use a large screwdriver to pry it in toward the center of the engine.
If you still have significant stretch, replace the chain, it's fairly easy (and not that expensive to have done, either). This will cure the late valve timing and improve low speed operation considerably.
If the stretch really is 28 degrees, check the compression, you may have already started damaging the valves.
Neglect is a terrible thing -- check chain stretch is one of the MB regular maintenance things a good tech will do every 30,000 or 60,000 miles at the "big service", but no one else every does.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!