Subject: Fw: [Summary] Run-In Oil??
>
> >
>
> > The key to run in is the finish of the cylinder bores. Modern machining
> > technique now achieves what is called "plateau" honing.
> > The bores should be as close to perfectly round and perfectly straight
as
> > possible within economic reasons.
> > The microsurface reflects two different types of friction on it, from
the
> > rings and from the pistons and the way the oil forms a lubricating film.
> > The pistons press against the side of a cylinder because of the
geometry
> of
> > the connecting rod and the crankshaft throw. During the power stroke,
the
> > connecting rod pushes the crank shaft in one direction but pushes the
> piston
> > with equal force in the opposite direction, with the center of piston
> force
> > at the level as the piston pin.
> > These forces vary on the walls during compression, part throttle, or
> other
> > high vacuum periods. So the piston varies in both the levels of force
and
> > the direction of force upon the walls.
> > The rings work in quite another way. Gas pressure from the combustion
not
> > only pushes the piston down, but the ring as well, through the gap
between
> > the piston and cylinder wall. The ring presses down against the
descending
> > piston and also gets behind the ring and forces it against the cylinder
> > wall.
> > "Seating" the rings means much less for the rings and MUCH more for the
> cyl
> > wall surface. It is the initial frictional wear of the engine block
during
> > the run in period that we should be concerned with.
> > Plateau honing can achieve this finish virtually eliminating the need
for
> > both run-in and ring seating. Final honing should be of a grit of at
least
> > 280.
> > In a perfect world the surface should retain just enough crankcase oil
> > thrown up by the spinning crankshaft journals to keep the minimum amount
> on
> > the surface for ring lubrication for one cycle up and down.
> > Lastly and most important is the final hot soapy water cleaning before
> > reassembly.
> > Any grit left behind will stay on the rings indefinitely and cause
> premature
> > wear.
> > The choice of oil is, well, what ever you want.....
> > Dave@Taos Garage Annex in Albuquerque
> > 59 AH :{) 54 BN1
> >
> > Click below for webpage:
> >
> > http://ibelong.koz.com/ibn/Sprite
> > ----- Original Message -----
> > From: "Larry B. Macy" <macy@bblmail.psycha.upenn.edu>
> > To: "Larry B. Macy" <macy@bblmail.psycha.upenn.edu>
> > Sent: Monday, January 15, 2001 9:09 AM
> > Subject: [Summary] Run-In Oil??
> >
> >
> > > Well, the on, and off, list opinion seems to be that using an organic
> oil
> > is
> > > best for the run-in period, There seems to some discrepancy as to what
> the
> > > run-in period should be and how it should be done. The consensus is
> that,
> > > and it makes sense, the rings won't seat properly if a syn oil is used
> > > during the first, 500 - 8000 miles (quite a range, huh?) the rings
won't
> > > seat properly. Has to do with the "slickness" of the oil. Syn is too
> > slick.
> > >
> > > So I will use an organic oil for the first grand or so. Then go to the
> > syn,
> > > just cause I like it. The OP stays higher when warm with Mobil 1 than
> with
> > > either Castrol or Valvoline 20-50. Well that is my experience. Or
That's
> > my
> > > story and I'm sticking to it. I always like the Valvoline 20-50 over
the
> > > Castrol because it seems to hold the OP better. Maybe right, maybe
not,
> > > maybe buggers, maybe snot.
> > >
> > > I changed to the syn in the first place because, as I understand it,
it
> > > handles higher temps better. That is that it does not loose it's
> > lubrication
> > > abilities at a higher temp as opposed to an organic oil. When I first
> > > switched over to an electric fan, instead of the water pump driven
one,
> I
> > > was experiencing a higher than, what I perceived to be normal, temp.
> Found
> > > out later that my temp sender was bad. But anyway, I find that the syn
> oil
> > > seems to hold the hi-temp pressure better than an organic based oil.
So
> I
> > > will be going that way in the end.
> > >
> > > To start, run-in with organic, then switch to syn.
> > >
> > > Thanks for all the advice, folks
> > >
> > > BTW I sent the same question to Mobil. I will forward their response
> when
> > I
> > > get it.
> > >
> > > Larry
> > >
> > > >Well Hello, Boys and Girls!!
> > > >
> > > >And How is Everybody Today??
> > > >
> > > >I am getting ready to reassemble the 1500 I have that is going to
> replace
> > > >the engine I have in the car now. I have a bit of a question that is
> sure
> > to
> > > >stir up a few comments.
> > > >
> > > >I have been running Mobil 1 15-50 in my engine for a few years. I
like
> it
> > a
> > > >lot. Now on the new engine I want to continue to run Mobil 1. However
I
> > am
> > > >unsure of using it for running in the engine. I don't really see an
> issue
> > > >with it, but I have not heard anything about it. I have heard that
> using
> > > >organic oil is preferred, but I just don't know why.
> > > >
> > > >Any thoughts on why I should or should not use Mobil 1 synthetic oil
to
> > run
> > > >in a new engine??
> > >
> > > Larry Macy
> > > 78 Midget
> > >
> > > Keep your top down and your chin up.
> > >
> > > Larry B. Macy, Ph.D.
> > > macy@bblmail.psycha.upenn.edu
> > > System Manager/Administrator
> > > Neuropsychiatry Section
> > > Department of Psychiatry
> > > University of Pennsylvania
> > > 3400 Spruce St. - 10 Gates
> > > Philadelphia, PA 19104
> > >
> > > Ask a question and you're a fool for three minutes; do not ask a
> question
> > > and you're a fool for the rest of your life.
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