How much shaft play is ok
03-21-2012, 04:07 PM
#1
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How much shaft play is ok OK so I just purchased a lightly used turbonetics gtk1000. The thing looks damn near brand new. But when you push on the shaft there is some side to side movement about .018. Which I'm more concerned about than the .002 end play that I measured. There are no contact marks but as I am new to ball bearing turbos I wasn't sure if there should be that kind of play. Any input is appreciated. Thx Nick
Last edited by baggins; 03-21-2012 at 04:14 PM.
03-22-2012, 12:23 AM
#3
Every turbo will have a little bit of play in them. As long as it's not excessive, or the wheel does not touch the cover it's fine.
This is in a journal bearing turbo, but you get the idea.
A full ball-bearing turbo is designed to have clearance between the bearing cartridge and center housing for hydrodynamic damping in addition to the internal clearances of the bearing cartridge itself. Hydrodynamic damping uses the incompressible properties of a liquid (oil in this case) and the space around the bearing cartridge to dampen the shaft motion of the rotating assembly. When the turbo is new, or has not operated for a long period of time allowing most of the oil to drain out, the rotating assembly will move more in the radial direction than a typical journal-bearing turbo because there is no oil in the center housing. This condition is normal. As long as the shaft wheel spins freely and the wheels don't contact their respective housings, the assembly will function properly.
