So, is there an easy way to tell if I've got too much blow-by? By easy, I mean requiring no $1000-dollar tools, and requiring no more than a couple hours of work; or possibly by evaluating the car's performance, oil consumption, etc.
I've got the same symptom as described above - the wisps of smoke upon removing the oil filler cap from a hot engine - but the crankcase pressure is also causing some minor oil leaks.
I think I'm going to plan on rebuilding this engine next summer.
'83 240D, 250k miles