If noone has pics can you describe what the internals look like compared to regular bearings.

 

Floating bearings are most common and what you'll find in a majority of Garrett, IHI, Holset turbos:


Ball bearings are almost the exact same setup but have a floating bearing with a u shaped groove for the ball bearings:



If you plan on buying a used ball bearing turbo, good luck with that. If you plan on buying a used ball bearing turbo and having a shop rebuild it for you, good luck with that.

There is a reason why 99.99% of CHRA's use floating bearings rather than ball bearings.

 

wow. it must be a major pain in the *** to rebuild a bb turbo. it seem like youd have to just put the shaft in just far enough to put the fist row of bbs in. then repeat the next row, etc etc. those bbs must be tiny

 

AFter all, it's HMT here, we can dig further than garrett's website and the few pictures they agree to show to the public. Should we?

First off, it's sad but as of now, garrett BB turbos can't be rebuilt. None of the internal components can be ordered from garrett. Even if you have a nice used BB turbo with shaft play but reusable wheels, they don't give a ----: Your only option is to order the whole center section with new wheels. You can't order just a "loaded" center cartridge without shaft/wheels. That sucks.
For example, the smallest BB CHRA, the GT25R, will cost you around 600$. Basically, it's a new turbo except the end housings that you have to buy, everytime you want to rebuild it and yes, they do wear out and fail just as easily as journal bearing turbos do.

Now, here's the meat we all want to see:


A BB turbo is like a can of worm or a pandoras's box: When you pull the shaft out, all the turbine side bearings jump in your face because the inner bearing cup remains on the shaft. It's press fitted on it. On the compressor side however, the sleeve including the inner bearing cup easily slides on the shaft so the bearings stay in. Funny enough, no thrust plate on a BB turbo...
As opposed to a journal bearing turbo that has oil injected through the bearings only and immediately flushed down the drain, the BB relies on "some" oil level within the center catridge that is forced through the bearings, and then exits through at the extremities. Oil tightness is insured by piston rings at both ends just like a journal bearing so poor drain and too much pressure on a BB would cause the same oil leakage problems than for a journal bearing turbo.


A BB turbo "could" be remanufactured because the external bearings cups are just a sleeve that is inserted (probably cryo-fit) into the center cartrdige.


The compressor side bearings will also jump in your face, as well as the brass crown retaining them, once you push the sleeve out of the cartridge. a combination of special tools, super thick grease or 4 pair of hands are required to put the bearings back in place.


On the turbine side however, there's no brass ring retaining the bearings. The ring is made of carbon-like composite and seems to quickly crumble away, sending debris all over your oil system as soon as the turbo picks up shaft play.

I forecast we will see an increasing amount of used BB turbos for sale on Ebay as people realize that they can purchase a New journal bearing turbo of equivalent performance for less than it costs to rebuild a BB....

 

Awesome info and pics!!!! Thanks a bunch. Feel free to post any additional pics you have of it.

 

Interesting. so BB turbos are more like disposable turbos... how long do they last? 300K mi? It makes me think twice about upgrading to BB turbos.

 

Fixed it for ya.

Sidenote- told ya so.

 

so you do learn something new, everyday... I was not aware of that.. then again.. im to cheap to afford those high end turbos...