In my last post I omitted to say that I had some rough starting after installing new glow plugs due to, and I'm embarrassed to say, a loose wire on a glow plug. The clue was that the glow plug lamp flashed after the engine was running - as if to indicate a bad glow plug - but it was just a bad mechanic!
The stainless steel expansion bellows on the exhaust connection to the turbo is not an issue here.
Ignore the oil on the glow plug threads, it's not indicative of a defect.
The rack damper pin on the old 5 cylinder 617 engines is on the aft end of the injection pump. But I'd advise against making any changes to it - if there is one on your six cylinder engine - for an additional variable is added to the equation - which hasn't yet been solved.
Your added description of the extended smoking leads me to believe that lube oil is being pulled into the engine through its valve guides whose plastic valve stem seals may be worn out. Or, much worse, that the cylinder head is cracked. Was this engine ever overheated?
An additional symptom of a cracked head or busted head gasket is rapid and unexplained overheating. You don't mention either so let's assume it's neither of these baddies. Short of opening the engine a compression test is the definitive way to know.
Before proceeding with any heavy $$ or work, I suggest you pose this problem to the Diesel NG on
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Many of these fellows own or have owned this engine and will give you more acute thoughts than I can due to their hands on experience. It's free but one needs to sign up.
Meanwhile, I'll look in my HD for a couple of pix of cylinder heads which I'll send you directly.
Tom