Q. for the turbo guys.

[Andre]

I've got a question that to this day am still kinda unclear on.

When used turbo's are sold the amount of shaft play is usually noted, as well as end play (IIRC). My question is; What is a tolerable amount. If I were to buy a freshly rebuilt turbo, never used would it have some shaft/end play? Or does an "ideal" turbo have no play at all?

I understand what shaft and end play is, but am curious whether there is a "tolerable" amount. Also, what is the result of too much shaft play? Does it meen a bushing is toast and it will piss oil? Does it affect the balance? Lose pressure? Or all of the above?

Spanks,

Hey Andre,

I have no turbo experience, but from a machining point of view, all bearing systems will have some degree of play to them. It reflects the tolerances of the bearing systems surfaces.

I've heard with turbos (I could be wrong on this) that excessive shaft play can result in the burning of oil, as it begins to escape the bearing assemblies and enters the exhaust or (even worse) intake stream. Also, as with any bearing system, wear is an exponential progression - excessive play will result in increased wear which will result in increased play - a cycle which quickly works toward bearing failure. From a turbo point of view, I'm not sure if this could mean seizure, or maybe putting a turbine wheel into the housing, depending on how tightly they are constructed. Certainly, the location of the turbine shaft is critical, and must be maintained.

This is just a guess, but I would think only a few thousandths of an inch (maybe less than 3) in end play is tolerable, but that might even be too much.

[Andre]

Yeah, that makes sense to me too. I see some advertised occasionally as "no shaft play" and am wondering if that's literal or a reference to the "right amount" of shaft play.

[b18a1+gsr-trans]

never buy a turbo that has ANY detectable end play, that is the seals. when they are new there should be a small amount of shaft play(just enough that you can detect it). For shaft play i have seen turbines and compressors that contact the housing because of the amount of play and never leak a drop of oil, on the other hand i have seen turbos that have next to no shaft play and burn or leak oil like crazy.

just to give you an idea of what part of the puzzle shaft play is, these are the things i check before buying a turbo;
shaft play (by touch)
end play (by touch)
nicks or chips on compressor or turbine wheels
oil residue in turbine housing
oil residue in compressor housing
any type of build up in the oil inlet or outlet
cracks in the housings
alignment of compressor nut and marks
and of course give the shaft a spin

so really the only rule of thumb for shaft play is, if anything contacts the housings dont buy it.
hope that helps

Ball bearing turbos typically have a little more shaft play than journal bearing units. Be careful about some of the old school "ball bearing" turbos. I think turbonetics sells a "ball bearing" that's really only 1/2 ball bearing. It's better than the journals but not as good as a complete ball bearing.

Ball bearing turbos are also not rebuildable. The 1/2 ones are but are expensive to rebuild. I'd ask if it's rebuilt as well and who did it. Anyone who did it themselves the turbo is basically junk until it's rebuilt and balanced. Many times when turbos burn oil it's because of excessive supply oil pressure. Many people wrongly believe that you "blow out" the oil seals. A turbo with oil in the housing is not necessarily a bad unit.

-Michael

[Andre]

Awesome, thanks fellers.

[boudz]

NA>BOOST

[Lancer]

The shaft play that you have to worry about the most is (front to back (compressor to turbine) If there is any play front to back the turbo is probably done. A little side to side play is normal.

The turbo I had for sale and no shaft play at all when new compared to a few new turbos I had bought from turbonetics and turbochargers.com
When used it still has barely noticeable shaft play. It happened to be the longest lasting and best turbo I have ever owned. Coincidence ?
Most of the other T3/T4 have averaged about 2 month of high boost use before leaking. The new one I just got lasted about a full day of high boost. That's it.

Most of them had horrible side to side and front to back shaft play when they where done. These turbos are not rebuilable and all you have left that is good is a turbine housing. The last turbo I had had a just a little noticeable shaft play but smokes a whole lot.

[BrettR]

Most of the other T3/T4 have averaged about 2 month of high boost use before leaking. The new one I just got lasted about a full day of high boost. That's it.

Most of them had horrible side to side and front to back shaft play when they where done. These turbos are not rebuilable and all you have left that is good is a turbine housing. The last turbo I had had a just a little noticeable shaft play but smokes a whole lot.

I am curious, which brands were they?

[Lancer]

Most of the other T3/T4 have averaged about 2 month of high boost use before leaking. The new one I just got lasted about a full day of high boost. That's it.

Most of them had horrible side to side and front to back shaft play when they where done. These turbos are not rebuilable and all you have left that is good is a turbine housing. The last turbo I had had a just a little noticeable shaft play but smokes a whole lot.

I am curious, which brands were they?

Mostly turbonetics.com
Also http://www.turbochargers.com (turbonetics dealer)
I had one good turbocharger from them but it was a smallish T3 super 60.

[kingpin]

wow. very informative. Thanks.

[kingpin]

ps, we need more thread like this. Or a dedicated section to informative little bits. just a thought

[BrettR]

Most of the other T3/T4 have averaged about 2 month of high boost use before leaking. The new one I just got lasted about a full day of high boost. That's it.

Most of them had horrible side to side and front to back shaft play when they where done. These turbos are not rebuilable and all you have left that is good is a turbine housing. The last turbo I had had a just a little noticeable shaft play but smokes a whole lot.

I am curious, which brands were they?

Mostly turbonetics.com
Also http://www.turbochargers.com (turbonetics dealer)
I had one good turbocharger from them but it was a smallish T3 super 60.

Yeah, I just recently found out they were outsourcing stuff to China, hence losing exclusive rights to brand new Garret stuff. Go figure.