David Hobbs wrote:
Howdy everyone.  Right in the middle of a head job and I am not replacing
the rings.  Any suggestions on whether I should bore out the cylinders
anyway?  There is some very minor cross-hatching on the surface.
Thanks
David

Reply:
  You say you see minor cross hatching. Does this mean the appearance of
concentric lines side by side appearing to be crossing with others at a 45*
angle.  If so this is exactly what you should see. If however you have
misunderstood the term and  you actually mean minor scoring in the cylinder,
then you have problems. A good way for a laymen to determine just what you
have is  if these marks are the same in all cylinders they are the visual
remnants of the original cylinder honing  from when the engine was built.
That is indeed cross hatching. If you see longitudinal or vertical lines
along the pistons travel path in the cylinder, that you can feel with your
fingernail, you do indeed have a problem and should fix it now.  It is
perfectly normal to see cross hatching in the cylinder wall, it is in fact a
good thing. But scored lines made by metal contamination or ring welding is
a very bad thing. If the cylinder wall has normal wear only, you will see a
hatch pattern and this is a very good sign your motor oil and maintenance
practices are very effective.  When you build an engine you must hone this
cross hatch pattern into the cylinder walls to best provide for piston ring
"break in".  It is vaguely reminiscent of a basket weave.  I myself would
consider any sanding of the cylinder walls to be non productive, due to the
fact that you simply cannot  ever hope to  remain concentric with it. A
cylinder hone does this quite well however.  Hope this helps to reassure
you, if it is cross hatching you have a good healthy cylinder wall.
  jeff/ Florida