Dave@Taos Garage Annex in Albuquerque
59 AH :{) 54 BN1
Click below for webpage:
http://ibelong.koz.com/ibn/Sprite
----- Original Message -----
From "frogeye" <frogeye at gateway.net>
To: "Larry B. Macy" <macy@bblmail.psycha.upenn.edu>
Sent: Monday, January 15, 2001 10:10 AM
Subject: Re: [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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