How should I polish the internals of an engine to create a smooth and carbon free surface?

I am just wanting to polish the internals with little to negligible amounts of metal being removed.

I was told 120grit would remove to much metal and that I should start with a higher grit. The engine I have in mind is a to two stroke so I'm not to worried about high tolerances.

  • Have you looked at any how-to guides for "port polishing" ?
    – JPhi1618
    Sep 12, 2017 at 15:31
  • I dont want to port, just polish. Sep 12, 2017 at 15:32
  • Right, I was just giving you something to search for if you didn't know the terms?
    – JPhi1618
    Sep 12, 2017 at 15:34
  • If you want some videos on this, check out Jafromobile on YouTube. I cannot recommend them enough. Highly detailed with explanation as to why he does stuff. Most all of his videos are time condensed so you don't miss any of the action, yet you won't get bored either. Great stuff. He has videos on porting, yes, but also about the polishing aspects, as well as the tools you'll need to accomplish the job. Sep 12, 2017 at 21:18
  • carbon removal and polishing aren't exatcly the same thing. If you want to decarbonize stuff for a rebuild, look into glass beading for cast iron or steel, and walnut shell blasting for aluminum. This will give you beautifully clean parts with no metal removal. "polishing" internals is usually reserved for racing engines to reduce oil drag, and maybe a little much effort for a two-stroke which tends to make more soot than a four-stroke. Cylinders should be honed, never polished, as a proper crosshatch is essential for oil retention between the rings and cylinder wall.
    – SteveRacer
    Sep 13, 2017 at 1:25


You must log in to answer this question.

Browse other questions tagged .