Topica Loopframe_Guzzi Archive


Subject: (no subject)

Author: David Otis

Date: Feb 4, 2001, 3:57 PM

Post ID: 1705272511


My thoughts on pistons, and cylinders.

A chrome cylinder is ok, as long as it is unpealing, and undisturbed,
(meaning on the engine NOT taken off of the piston) so the piston and rings
are in the exact position they were in when they were first installed
because the rings have to seat to the cylinder wall if you change this it
will not be the same.

You cannot do new rings in a used chrome bore and expect good results, the
rings need the rough surface (that is why we hone cylinder walls) to seat,
they will not, and you'll have problems. You cannot hone the chrome without
taking off too much material and changing the piston to cylinder clearance.


Sleeving cylinders is a reasonable solution, but you have some issues to
consider there too. First make sure your pistons are in excellent condition
and not out of round, which is how the tend to wear. make sure you have them
installed with a negative clearance, and the piston to wall clearance is
proper, as expansion and contraction of the sleeve and piston will be
different. too close of a clearance wil cause the piston to expand and
seize.


Nikasil replacement cylinders are the easiest and best way to go, but
expensive.

I have experimented with all of these and these are my humble opinions.


David J. Otis
Principal Engineer
VPN Solutions
V-ONE Corporation
301-515-5200 X 5621

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