turbo grinding?!?

[redsx13]

To start off i have a s13 sr w/ s14 turbo. So just recently my turbo has started to make this grinding type of noise at idle. The noise can also be heard for a second or two after the engine is turned off and the turbo is still spinning. The noise is strange though because it is not continuous, meaning that is is not one steady grind, to put it into the best context it sounds like.... grind......grind grind..grind.........grind..grind....grind.
anyone herd of this before? I have no smoke from the tailpipe or anything.
I do have shaft play, its not that bad though. How much shaft play is really allowed?

[HYPNOTIK]

Apparently your shaft play is bad enough that the fins are rubbing the compressor housing. You need a new turbo.

[redsx13]

HYPNOTIK, you are correct, my turbo blew today, sucks.