6-71 rebuild questions

[Muffin77]

Dont really know where to ask but here it goes. I recently got a 6-71 for free from a family member that was going to scrap it. I was told that the case is pretty much the only thing you reuse in a rebuild. My questions is how deep can the scratches be? There are like 5 that catch my nail but none really deep or wide. Also there is a little bit of oxidation as well. Can this be cleared up by buffing or polishing?

[raceman6135]

Minor scratches are not a problem because there will be a few thousandths of an inch clearance between the rotors and the case on the sides as well as on the ends -- the rotors shouldn't touch the case and they shouldn't touch each other.

If you plan to run Teflon strips on the edges of the rotors, you will want to make sure that the scratches are polished in such a way that they do not grab the Teflon strips and pull them off the rotors, and that the scratches won't prematurely wear the Teflon.

Most oxidation can be removed with typical aluminum polish, but if this blower is as trashed as it sounds, the oxidation may have damaged the parent aluminum too much, and you may have a lot of trouble totally cleaning up the "pock marks."

As for the rebuild, you should be able to reuse the case, front bearing plate, rear bearing plate, rotors, and gears. It would be wise to replace the bearings and seals at both ends of both of the rotors, but in most rebuilds, those are the only parts that need replacing.