how can i tell how much shaft play is in the turbo?

Take the intake off the turbo, and push on the shaft, and move the shaft up and down. Its acceptable if the shaft moves a TINY bit if you push on it. When I say tiny, I mean tiny tiny tiny. If it moves up and down alot its got too much play.

Turn it and if theres ANY touching of the fins on the housing you need a rebuild.

This post has been edited by Supersprynt: May 29, 2007 - 12:43 PM

by moving the compressor wheel side-to-side and see if it hits the compressor housing. thats bad if it does. also slide it front to back. excessive play becomes noticeable when the compressor housing starts to get chewed up from the blades touching it. some shaft play is fine, aslong as your not burning oil and you can spin the compressor wheel without it hitting anything.

After reading this i realized how useful this info could have been about a year ago. Id say this would be a good add to the stickies. Info was short and to the point. Could prove useful to others

Different turbos have different allowance.
For CT26, axial play (in-out) must be less than 0.13 mm, and radial play (side-side) must be less than 0.18 mm
And here is the correct way to measure radial play.
Most of the time, you are only able to move it at the compressor side.