MC1 engine with slightly rusted cylinder bores...honing?
Frederick Smith
smitty at pcrealm.net
Sat Mar 2 20:08:27 EST 2002
Honing will "break the glaze" that has occurred from the millions of miles
of piston travel in the bore and it will also remove light surface rust
deposited due to the bores being exposed to damp conditions. It will
refresh the cross hatch finish of the cylinder that aids in piston ring
seating and oil control, if done properly.
Deep pitting and scaring of the bore will require boring. For instance
if a motor had a bad cylinder head gasket and the bores had water sitting
in them for months or years while idle, the bores would have a band of
corrosion where the low side of the piston was at rest. This type of damage
requires boring.
Honing is used as a " touch-up" after boring and removes very little
material compared to boring, which is used to resize/enlarge. A boring bar
actually pilots on the center of the existing cylinder removing + amounts
from the circumference. Honing uses a light tension on the stones that
keeps them expanded on the bore surface but with far less outware pressure
than boring. The outward pressure is caused by the hone being spun by a
motor, could be an electric drill or a motor an a cylinder boring machine.
I guess a simple way to think about it would be boring=cutting,
honing=finishing.
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