<VV> Turbo anomaly

[Grant Young]

I a trying to help someone sort out what might/might not be a turbocharger problem on a new engine. This engine was recently rebuilt (with chrome moly rings, I think) and only has about 50-60 miles on it. The carburetor and turbocharger were also rebuilt at the same time. The problem is that the manifold intake cross tube is getting a lot of oil in it. Engine used a pint of oil in 30 miles. I was asked to check the carb and turbo. Both appear good. I paid extra attention to the turbo since I think that has to be the path the oil is taking. Can't find anything wrong - good carbon seal and o-ring, no excess play in the bearing or shaft, sealing ring and washer are good, and all indications are that the piston ring was installed properly as there is no indication otherwise and it is still good, no cracks, good gaskets, etc. Unit turned like it should by hand. 

There is much too much soot on the hot side (on the turbine and heat seal disk area) for 50 miles of operation. It is a moist soot, if that makes sense. The engine doesn't smoke, just doesn't run well or boost, probably due to the oil into the intake, but not sure. The spark plugs checked okay. I have successfully rebuilt 60+ turbo chargers and hundreds of YH carbs, and don't see anything amiss. This is not the first engine the person has rebuilt. Looking for tips or hints or clues or advice. (Could the oil be backing up in the drain tube under pressure, for example).
Help! and Thanks,
Grant