My problem is more than the usual idle problem,I fixed that last year with a tune up and a bottle of "Techron"
I have a definite miss.
it doesn't change when warm
But I can hear the valves when cold,that noise goes away when car is warmed up,that leads me to beleive it needs valve adjustment.
The valves are hydraulic but can be adjusted.The "shims"must be replaced with the correct thickness shims to do this.
I have had a lean spark plug problem on the right side,and not much pressure when I crack the lines at the fuel distributor.
However I did not have this problem at all before the head rebuild.
I also may suspect plug wires/ends ?

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'60 190b
'77 300D
'78 240D
'82 300TD