Just finished a rebuild/conversion of a 14b into a s16g using the Turbolab $50 rebuild kit (superback kit.) I noticed that the compressor wheel rubs/binds on the chra/bearing housing. Initially I thought it might have been a difference of dimensions, but I checked the dimensions of the journal bearings, thrust plate and collar, and all of the tolerances seem to be in spec (differences of +/- .00x)

After taking the whole chra apart and putting it back together, I decided to slip the compressor wheel on without first installing the oil shield snap ring, just for kicks. Lo and behold, the compressor/turbine assembly rotates without binding on anything.

So, installation of the oil shield snap ring "pushes" the oil shield far enough into the bearing housing that the compressor can then rub on the bearing housing itself. I tried this with both the new snap ring provided in the rebuild kit and the old snap ring, and both exhibit the same behavior.

Has anyone experienced this before? Am I missing something in the rebuild?

Are you putting the snap ring on the right way? Also is the 16g compressor wheel the same as the 14b wheel on the back. Flat or concave?

Did you have the bearing housing machined for the larger exducer?

Backplate groove on the bearing housing will need to be opened-up 2mm to roughly 61.2-61.5mm or it will rub for sure. A Small 16G compressor will not fit on a 14B bearing housing unless machining is done.

^^ Exactly what I was getting at

Dangit. I missed that one in my research. I was under the assumption that the backplate would only need to be machined if I was using big 16g wheel... Thank you for the help, guys.