[Vwdiesel] Seeking experience or data on Petter stationary diesels

Tue Jun 14 15:49:45 EDT 2005

'H' 'R' and 'J' very interesting banter; but I've just
switched my serious head on...
The grease will only create a hydraulic ram ouyt of the
piston and bore if  you have a complete rust up else it will
simply pass the split in the rings. Only way I've ever done
it is with head off and a soaking with paraffin and a wooden
mallet. Ideally engine not frozen at TDC or at worst BDC.
for a one-man-job strap a 56 lb weight to a bar on the
flywheel to help torsion on crank whilst tapping... Never
failed for me but then I've only done a couple of handfuls
of engines; not like you ol' sages....
Bright-Spark-Mark

Hansen wrote:
> Never use
> anything that is compressible on something that is stuck.
That's called an
> airgun/bomb. baaaaad.  Use incompressible fluids, grease
etc, never air.
> never never never.  If it decides to spew chunks, they fly
with a great
> velocity imparted by the energy contained in the
compressed gas.  If you use
> grease, oil, etc, and the block completely fractures into
tiny bits, the
> energy contained is tiny, and the bits drop to the floor.

When I first started working for NASA, one guy took me to
see one of the hypervelocity guns they use for meteroid
impact
studies.  Basically it is a big, long, heavy steel tube,
with very high pressure gas behind it.  Fires small
projectiles very
fast at targets to study the cratering damage.

Anyway, when they first built it, they did a hydro test on
it, up to 10,000 psi or something like that.  Apparently
some part of
the gun failed under the test and blew apart quite
spectacularly.  Folks were standing around observing the
test and I think
some were hurt, not sure about that.  Anyway, the point of
being told that story was to not ignore the normally
negligible
things, like water is incompressible.  It is, just ever so
slightly, and if you compress enough of it, to a high enough
pressure, it does store a fair bit of energy.  Same thing
with the steel, it also stretches and expands under the
pressure.

Granted those are extreme cases and some not likely to be
experienced in everyday life.  But every time someone
mentions
incompressible fluids, I recall that story.

I've not heard of the grease trick for cylinders, but had
for removing things like pilot bearings stuck in flywheels.
Pump the
back side of the bearing full of grease.  Then use a wood or
brass rod the same size as the bearing ID, then hammer it
into the
center of the bearing.  The backside pressure of the grease
usually pops the bearing out.

--
James Hansen wrote:
> Never use
> anything that is compressible on something that is stuck.
That's called an
> airgun/bomb. baaaaad.  Use incompressible fluids, grease
etc, never air.
> never never never.  If it decides to spew chunks, they fly
with a great
> velocity imparted by the energy contained in the
compressed gas.  If you use
> grease, oil, etc, and the block completely fractures into
tiny bits, the
> energy contained is tiny, and the bits drop to the floor.

When I first started working for NASA, one guy took me to
see one of the hypervelocity guns they use for meteroid
impact
studies.  Basically it is a big, long, heavy steel tube,
with very high pressure gas behind it.  Fires small
projectiles very
fast at targets to study the cratering damage.

Anyway, when they first built it, they did a hydro test on
it, up to 10,000 psi or something like that.  Apparently
some part of
the gun failed under the test and blew apart quite
spectacularly.  Folks were standing around observing the
test and I think
some were hurt, not sure about that.  Anyway, the point of
being told that story was to not ignore the normally
negligible
things, like water is incompressible.  It is, just ever so
slightly, and if you compress enough of it, to a high enough
pressure, it does store a fair bit of energy.  Same thing
with the steel, it also stretches and expands under the
pressure.

Granted those are extreme cases and some not likely to be
experienced in everyday life.  But every time someone
mentions
incompressible fluids, I recall that story.

I've not heard of the grease trick for cylinders, but had
for removing things like pilot bearings stuck in flywheels.
Pump the
back side of the bearing full of grease.  Then use a wood or
brass rod the same size as the bearing ID, then hammer it
into the
center of the bearing.  The backside pressure of the grease
usually pops the bearing out.

--
    Roger

I Hagar as usual  is in lockstep with  James Hansen and
Charlie Brown (almost)
Roger Brown.   ----NASA ? not bad .    I can NOT top that
one.

I have to pipe in ----as I have oodles of experience  with
high pressure testing   -----IMHO
they both got the right angle on the stuff.
For the newbies here  ----in Industry  ---the greasegun
removal of Bearings and High Voltage
Insulators ---is standard procedure.  -----and that old
greasegun on the rack ?    ---shit
10 000 psi   is normal.

DO NOT  pressurize a nipple before making sure ---check ball
has been removed.--
READ MY LIPS.