how "free" should a turbo spin

[Mikey von]

just got my used banks from ebay. It looks good to me, but I don't know jack.

It is still attached to the manifold. The turbo has no play in it. I can spin it freely, but it wont freespin (once i stop spinning it it stops). Is this good or bad?

 

[BKinzey]

It's probably fine. You could try using WD-40 as a douche and see if it helps. Since it runs with a supply of engine oil in it I doubt you'll notice any difference anyway.

 

[mstockton]

It has no engine oil pressure to it sitting on a bench, but a turbo impeller spins at 120,000 rpm at full load, about 30k at idle....your bearings have to be in good shape to last...see if you can tell if any oil has leaked by the seals as well, but if you want to get a good feel for it, lube the bearings up and try it again. Remember to keep contamination out of the oil ports, dirt or grit + close tolerance bearings + high rpm = bad time.

-Martin

PS Also, a slight amount of side (axial) play is ok, as long as there is no evidence of housing contact from the impeller, but the main thing you need to be concerned about it fore and aft play, this wear comes from the impeller spinning up and forcing itself into the bearings. Also look at the edges of the fins, if any erosion is evident, you might want to pass..

 

[87 Blue Beast]

most of them will be *alittle* tight when they areny on the vehcile. as others have said, they have a constant supply of oil going to them. but even if you have oil in it, it still wont spin completely freely because they are meant to spin perfect when they are hot, since they get extremely hot when running. as you know, oil thins out alot after it gets hot, so that alone will make a differece, between haveing hot or cold oil in it. but as you said, if there isnt any side to side or up and down play, you should be fine

 

[Mikey von]

thanks for the replies. i have not had a chance to touch the turbo, but will update when I get there.