Hi guys I've got an m62 blower I'm using for a custom project. I picked the charger up used, and upon disassembly found the tips of the rotors have some small scratches and there are some small burs inside the supercharger case. It looks like some tiny grit got in there or something. I was wondering if it is ok to take some very fine grit sand paper or emory cloth and just smooth up the inside of the charger so that the burs are no longer there? I already plan on fulling chemically cleaning the case and replacing all the bearings, so no worries about getting grit inside of them. I'd just rather prevent any future damage. I know it would probably be best to start with a new charger but I only plan on running between 5-8 psi off this one.

I would keep the compression area smoothing to a miniimum. Burrs can be a problem, lower compression because of too much burr removal would be worse though.

there are just a few you can feel when running your fingers on the inside of the case. Should I just leave them along or just try to smooth them out a little?

That would depend on your intentions. I might smooth them lightly trying not to take any material other than the burr.

if they left grooves in the rotors, I'd leave them to keep the seal. And DO NOT soak the intermidiate plate to clean it. The bearings in the middle plate (with the rotors pressed in) cannot be pressed back together without a factory jig to keep proper clearances. hang the rotors in the cleaner if you must get the carbon off them, but do notwash out those bearings. And do some research on your cleaner first. If you have it, the 94/95 M62 (Gen 3) has an epoxy coating on the rotors that some cleaners can strip off. That coating provides sealing to prevent boost loss.

Ok cool, thanks for the help guys, I'm just going to take out the high spots on some of the burs. It appears this is a gen 3 as there is a dark coating on the rotors(not carbon buildup)

When clean, gen 3 rotors will be grey, gen 2 will be bare aluminum. Dirty, they look pretty similar.

You can tell a Gen 2 by the case ribs that go all the way to the base. Gen 3 ribs only go about half way down.

I wouldn't touch the compressor housing with anything, or clean the case. The carbon buildup over time helps seal the grooves and increase efficiency.

If you take off the high spots, you're wasting your time. There'* probably already matching grooves in the rotors.

The only abrasives you use should be smoothing the inlet and outlet of burrs and casting flaws.

Thanks guys I've decided to just leave it alone and replace the bearings. It is a Gen 3 as the fins don't go all the way down the case, and the rotors have a grayish coating on them(not bare aluminum)

Let us know if you need any tips on bearing replacement or sources for parts.