Yes, I'm thinking that my next move is to remove the head, something I've been avoiding as it is a lot of work and it doesn't seem to be the problem, but for lack on any other ideas I think I may need to do it.
The balance shafts are run off the crankshaft by a chain within in the oil pan area. From what I understand, the purpose of these shafts is to smooth out/change the engine’s resonant frequency as it was an issue in earlier versions of the engine. It looks as if the engine would have to be pulled to get the oil pan off to get at these shafts. If it comes to this I’ll probably junk the vehicle.