Question for Patrick or other turbo Expert

[Kevin87TurboT]

Patrick,
How much up and down movement is permissable for the new DBB 6776? I have two of them and both nearly touch when you move them up and down. I'll try to get better idea of exactly how much movement...but guess around .040" up and down and maybe .015" in/out. You can push it down and trap a sheet of sheet of paper between the wheel and housing.
TIA,
Kevin

 

[RUQWKNF]

Questions you have.... Answers you seek....

The Garrett DBB cartridge does indeed move more than their journal bearing cousins. We used to get this type of question all the time when I was at PTE. Believe it or not, it is normal. As long as the wheel do not touch down, the movement is acceptable. As you can see in this picture, the turbine wheel shaft goes completely through this self contained cartridge. The shaft basically floats on a pressurized film of oil. The gyroscopic effects of the rotating assembly when spun up to speed of 80-130k rpms, also help to keep the shaft centered inside this self contained cartridge.

This clearance is slightly more than the journal bearing setup. Every dbb turbo that I have ever touched or spun when it was on the shipping bench waiting to be boxed up had the same amount of play. As long as the wheels do not touch or rub the housings, it's good to go. Also, these turbos do not have the same type of oil seals as the journal bearing turbos. This is why they tend to leak if you have too high an oil pressure (more than 80 psi under WOT or cold idle) or if you try to over feed it with too large of an oil feed line. (-3AN or -4AN is typically what is used) This is also why each one comes with a restrictor fitting. I know my TE-60R out of the box had the play that you are talking about and on that particular turbo, all that PTE did was bolt on the compressor cover and turbine housing. That cartridge came directly from Garrett pre-assembled. And I'm pretty sure you can get not only the complete 6776RS turbo (Aka TO4Z) from Garrett, but also the cartridge pre-assembled directly from Garrett as well. To answer your more specific question as to how much up and down is acceptable, I do not know. Probably the only two people that might know would be Jim in the back, or maybe Harry himself.
Hope some of this helps.

Patrick

 

[Kevin87TurboT]

Thanks Patrick. I feel better about the turbos already. It just surprised me how much movement they had. We will try them and see what happens!
Kevin