The valves adjustment on these cars is simple, but difficult and frustrating to do without the special wrenches. The set is over $50 but you could make a set by buying two cheap, long 14MM open end wrenches and bending them as needed to fit onto the cap and locknut. If you don't have the specs let us know. I know the settings for a non turbo, but I believe your '82 is a turbo car.
You will need to bend these wrenches to match each other, that is lay over the top of each other. They both will look sort of like: _/- with the minus sign higer picking up at the top of the slash. I hope this makes sense and helps.
I have successfully adjusted the valves on a 240D without the wrenches, but it was a big challenge. On a five cylinder, there is a valve at the back that just cannot be done without bent wrenches, it's difficult enough with the wrenches.
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in