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Necessary to cross hatch Nikasil cylinder bores?

I have an engine repair company...I repair gasoline model airplane engines..
I am a member of a forum, Flying Giants...We are having an ongoing discussion about honing cylinders after replacing worn piston rings...There are two schools of thought...Cross hatch the bore to allow the rings to seat, or leave the smooth surface alone, the cast iron rings will quickly seat..I say the Nikasil was diamond honed at the factory and any further cross hatching is not desirable or even necessary...Maybe someone can answer this in a manner that the OLD timers on the forum can accept...Thanks in advance, Ralph C...

Ralph Cunningham
Gas model airplane engine repair - Williams, Arizona
March 7, 2009

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I think that you would be better off oversizing the rings just enough to work.
I think that you would be very unhappy with the cross hatch bit. I think that it will go through rings faster than you want and you very probably will have to send it back for replating and grind far sooner than you would like. It is not cheap.

James Watts
- Navarre, Florida
March 11, 2009

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Nikasil is really hard, so the original diamond honing may still be present. If so, just give them a good cleaning and leave alone. Some folks "hone" with abrasive pads (aka "Scotchbrite"), but I doubt they do much more than cleaning. Diamond hones will cut Nikasil, but great care is needed since the Nikasil isn't very thick.

BMW recommends that they not be honed at all.

If the bores are still within tolerance, I'd leave them alone.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
March 16, 2009

When cleaning Nikasil cylinders, is it ok to use muriatic acid? Is there any specific way to use the acid?

J.p. arrau
- new hyde park, New York
September 11, 2009