For use with CPN and CPN2 piston rings, it is recommended that you
plateau hone with a cylinder bore cross hatch angle of 35-40 degrees.
To reach this roughness, the manufacturers of honing machines and
accessories recommend using the following stones for a gray cast iron
engine block and Nikasil cylinders.
• Conventional stones: #220 – #280 grit; or
• Diamond stones: #325 – #550 grit
After honing with either the conventional or diamond stone, the same
manufacturers suggest to finish your honing by smoothing the surface
with a fine grit conventional abrasive (#400 – #600 grit) or to sweep
the bores with a flexible brush or a nylon bristle plateau honing tool.
This is necessary to get rid of jagged peaks and folded or torn
Be sure to confirm with your honing equipment manufacturer that the
recommended stone grit will produce the following Rz and Ra roughness
Rz = 59 – 138 µ in [=1.5 – 3.5 µm]; or
Ra = 15 - 35 µ in [=0.4 – 0.9 µm]
– Tech Tip courtesy of CP Pistons