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**jerry wass** · October 2nd 08, 03:41 PM posted to rec.aviation.owning,rec.aviation.homebuilt

wrote:
On Oct 1, 11:29 am, "Paul Dow (Remove Caps in mail address)"
wrote:

Does anyone have a technique to get the piston out? Preferably while
doing the least amount of damage. (So no explosives, please!)
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I don't see any easy-out for this one.

I assume you're willing to sacrifice the piston in order to salvage
the cylinder, in which case you might try soaking the piston with
liquid nitrogen or other cryogenic that should allow you to shatter
the piston along the ring-groove.

Depending on how much of the upper portion of the piston is obscured
by the wrist pin, you might consider fabricating a fixture of some
sort bearing a number of high-gauss rare-earth magnets, the idea being
to cause the ring to be drawn back into its groove whilst the assembly
is under tension.

In a similar vein, the suggestion about using the piston to remove the
cylinder liner would appear to have merit. You should be able to rig
the assembly so as to create considerable tension between the cylinder
and the piston. The manual should give you some idea as to the
required temperature difference, which would be obtained by raising
the whole assembly to a given temperature then hitting the piston AND
liner with liquid nitrogen.

-R.S.Hoover

This idea is the best so far--I would recommend hanging the assy. by the
rod, and attaching heavy weight to cyl head.. Then apply heat to barrel
of Cylinder.

I keep some old Coleman thermos bottle liners (vacuum bottles) then go
out to propane storage tank, crack the liquid line ,and after the valve
& line has chilled, introduce liquid into vacuum bottle...Careful--
the temp is -42°C-(-62°F)AND of course the vapor is highly flammable,and
1.5 times as dense as air--so it settles in low places.

Extinguish all fires & pilot lights---WEAR GOGGLES---The liquid will
boil violently upon contact with the hot metal---You have to do this
when you live 50 miles from Mr.Linde--& he might not have any liquid N2
that day anyhow..
Jerry