Re: [ihc] Re: David's "diesel" 258

["Jim or Ginger Aos" <jaos@xxxxxxxxxxxxxxxxx>]

> > On Aug 19, 2004, at 10:18 PM, Steven Stegmann wrote:
> >
> > > John,
> > >
> > > I've never done it but have heard of it.  Seems like
> > > I've seen that in some race engines too.  It might cut
> > > down on the friction???
> > >
> > > Steve
> >
> > Steve,
> >
> > No, it's the other way around. You do the knurling to pistons whose
> > skirts have worn excessively. So, the bumps created by the knurling now
> > contact the cylinder wall.
> >
> > John
> >
> > John Hofstetter
> > Ol' Saline
> > www.goldrush.com/~hofs
> >
>
> But a knurled piston only contacts at the bumps, whereas a non worn piston
> contacts in a lot more area, correct/
>
> In that case, wouldn't the knurled piston have less drag than a new one?
>
> -Ryan

Visulize two bearing surfaces with an oil film between.  Now replace one
surface with a rough surface and cavities for the oil to hide in, and the
protrusions to make metal to metal contact.

Jim A.
>
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.740 / Virus Database: 494 - Release Date: 8/16/04