Thread: Turbo shaft play

The turbine shaft floats on plain bearings IE a film of oil, so it has to have a certain amount of radial clearance/ movement. As you suggest it looks quite alarming the further away from the bearing journal it is measured.

Generally, if you deflect it sideways with you fingers and there is a visible gap between the compressor wheel and the housing then it should still be quite OK. There are specs for this but it really needs to be out on a bench with Dial indicators etc to measure correctly. Also shouldn't have any excessive noise under boost and obviously not blowing oil past the seals.

Is it a factory fitted unit?

JC

Thanks, based on your description the turbo is fine. It would be a bad day if the turbo decided to throw bit's of metal through the engine. I would rather prematurely change the turbo than risk an engine rebuild.

Originally Posted by justinc

Is it a factory fitted unit?

No it's not. It's off a Mercedes Sprinter van.

Myself and Vern did rebuilds of a couple of turbos a few weeks ago, and we had the same misgivings as you did with one of the turbos. However the *questionable* turbo, when compared to one that had just been rebuilt with new bearings and seals, both had the same amount of play. As JC said, there has to be a certain amount of play to allow the bearing to sit in a film of oil, and the movement looks more amplified the further away from the bearing you get.

As much as I can be sure about a turbo that I haven't seen first hand, I wouldn't worry about it. Particularly if there is no chipping of the impeller blades, or scorching, or anything else that would indicate that the turbo was on its way out.