Garrett turbo rebuild questions

[mog5858]

Hi Guy's I working on giving my hard-working yard loader some TLC as she never let me down so I have to show her some love. the turbo is off Caterpillar 922B 59A4168. Garrett 4M0289 serial number 00304. it was leaking oil into the cold or intake side of the turbo as well sometimes I think I could hear the impeller touching the housing. I measured the end play .004-.005 endplay and .012 radial play. getting ready to put things back together and I am not sure how the Hot side of the turbo seals the oil in. It looks like there 3 groves that may have cast iron piston rings but can't see or find anything in my parts book showing them or is it like a labyrinth seal and the exhaust pressure keeps the oil on the inside? there's .010 clearance between the shaft and the I.D. of the housing. second thing where does the oil hole in the turbo shaft go to? I got the hole cleaned out but not sure if there is another one that is blocking that I not seeing. is the grove at the back of the shaft for an O ring of some sort? I was able to get new bearings and thrust plate as well as the seal for the cold side. here are a few pics as I know everyone loves them

 

[mog5858]

a few more pictures to help clarify what I asking.

 

[OzDozer]

Early turbos used the spiral labyrinth seal groove arrangement to seal the oil in, later turbos went to a piston ring seal arrangement. There are no o-rings in turbos, they can't stand the heat a turbo produces. Turbos have larger operating clearances than other shaft and bearing setups, as the heat levels in a turbo reduce the clearances when running.
I'd be looking for another oil hole in that shaft, just the one hole doesn't seem right to me.
There have been so many design changes in turbos, it's hard to list them all, and it's even harder to find details on early turbo designs.
Cat fitted their first turbo to the new D353 engine in the new D9D in 1954.

 

[mog5858]

thanks for your help and insight. I will start looking for a labyrinth seal maybe I can get something from Garrett or recut the housing for modern piston rings. I will take another look for a second Oil hole.