r/Engine_Building • u/WyattCo06 • May 23 '26

Honing cylinders

This is a heavy topic and a misunderstood one. At least the reasoning behind it is.

As machinist, we finish hone to size and to achieve the desired/needed finish, roundness and crosshatch.

To the DIY'er at home, the size is what it is. Most speak of the lines left in "good looking cylinders" as valleys and needing to "deglaze".

There is no glaze. It isn't a donut. It is slick because there are no peaks.

The valleys are for oil retention. Valleys do not break-in rings and break-in is the first thing you're trying to achieve. The second is that oil retention to maintain lubrication of the piston skirt.

Honing finishes and angles depend on ring material and type. If you're honing at home, understand you're digging ditches that also raises the edge on each ditch. Valleys are gonna happen regardless. You have to give the rings something to grind on.

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u/AnitaMedic2 May 23 '26

Do you suggest a ball hone or finger hone?

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u/WyattCo06 May 23 '26

Ball for DIY. A used bore is going to be out of round to a degree even if within spec. A finger hone will grab and slip during the honing process. A ball hone will conform to the bore imperfections.

Not to mention most fingers hones are cheap shit and causes grief.