I thought its just the usual noise of the RB generation engines. I have had a N/A VL with the RB30 which was imaculate and It only had 50'000 ks and it made a faint ticking noise, I also had a VL turbo RB30et which did the same thing and so does my skyline only very faintly, I may be wrong but thats what I thought,
my 2 cents anyway
Cheers
JL