A Very Small Scratch in Alusil Piston
 

Hi,

I made a very small scratch in one alusil piston while trying to remove a stubborn clip. Would it be recommended to file or sand it down enough to make it unnoticeable to the touch? These pistons look perfect otherwise.

I know it would be great to get CP pistons and replate, however I would like to use these pistons.

Thanks
James

I wouldn't worry about it. The rings are touching the cylinder wall the piston does not make contact with the cylinder wall. Maybe use some emery cloth on the scratch.

DSS Racing actually cuts grooves in the piston skirts.
Some hypothesis about carbon deposits having room to escape without damaging the cylinder walls.
Anyway I wouldn't worry about a scratch.

I would burnish it out, just don't make it deeper.

Ok Thanks for the replies. I was vary disappointed in myself for making the mark. I will try to remove the edge.

Thanks again
James

Just use something like 220/320 wet sanding paper and your finger tip with water. Don't over work it.

When I did the top end on my 81 in the 90's, there was a vertical score on one of the alusil pistons. Something got in there. Piece of carbon?

It was not huge but it was definitely there.

I did not touch it as it went right back in where it came out. Doing fine 22 years later.

Thanks Bob.

Don’t mess with it. The aluminum piston is softer than the cylinder wall. The scratch won’t matter. If you try to “fix “ it, you’ll remove the ferrous coating on the piston. That coating is there too keep the pistons from “gauling “ with the aluminum cylinders.