Steve,
What follows is not exactly an answer to your questions. But, the forum
has this type of issue come up constantly. First, you have had the
correct answer given to you. Don't use a multi grade in that engine. It
is difficult to identify whether your continued questioning is related
to bullheadedness or simple, natural curiosity.

There are a number of issues in all this that are worth some discussion.
The archives have excellent and thorough answers to most of the
questions that come up, over and over again. Like many others I am
disinclined to repost a shortened set of posts that have already been
posted. Or, to spend the time to write a new post or series that I am
not convinced I could improve upon. Off line I have had some discussion
with other key posters, that it becomes tiresome, trying to post fresh
material, especially if there is some appearance that the post(s) will
be ignored.

In the case of your question, it relates to a general issue that
generalizations simply don't apply. In other words, the Lehman engines
are a specific case and your comments imply "used in millions of
trucks", that all engines are the same, or that millions of engines are
enough like a Lehman that the same oil recommendations should apply to
it as to all those other engines. It is not true that other engines are
enough like a Lehman to use a blanket recommendation.

The Lehman case is like many other issues in boating and life in
general, in that solutions that were appropriate for older technologies
are not appropriate with the latest technology.

For instance, I just got off the phone with a friend. He is trying to
replace a broken window in a boat. He tried gluing in a plastic
replacement with 5200 and the bond failed within 2 days. The acrylic
plastic must bond to the sealant; the sealant to the aluminum frame. He
may need 2 different primers to use on the plastic; and another to use
on the aluminum. There is also a long term issue of UV degradation of
the sealant/adhesive that may require some sort of plastic tape on the
outside of the plastic to protect the sealant from destruction. Frankly,
I don't know exactly what he should use, but his simple solution might
have worked just long enough to fool him into thinking that it was
really solved; obviously, not so.

As for curiosity; it is a perfectly legitimate desire to know more, but
the fact is that if you want to know about oils, there is plenty of
material on the internet and it is easy of access. Expecting Bob Smith
or any other expert to answer your questions here in the forum is not
very realistic. In case some of you are not aware, Bob monitors the
forum, but like many other well informed individuals is disinclined to
get sniped at by poorly informed posters, with the attendant lack of
courtesy which too many discussions deteriorate.

The forum is an imperfect place to solve problems. It is a worthwhile
place to get pointers as to where to find answers.

What I have mentioned here is pretty well known by most of the forum,
but newcomers often times don't understand why the forum does not work
any better than it does. Don't assume that I think this covers all that
could be said about how to have a better forum.

And don't start wondering, if I can write this much out, why did I not
just write out the detailed answer about oil? If you teach a man to
fish, he can feed himself. If you just give him a fish, you have made
him dependent and he has learned nothing useful. And then, who will
teach the younger generation?

Regards,
Mike

Capt. Mike Maurice
Beaverton Oregon(Near Portland)

Steve,

Following along the same line as your question,  I called the Shell Oil
"Chemistry Dept." and their comment was - if you wish to take advantage of the
advancements made in the new lubricating oils, you must go multi-grade.  He
inferred that the single grade motor oil being sold today wasn't a lot
different than the single grades of 20 or 30 years ago.  Maybe that's all the
older engines need?

To get into this deeper, I got the manual out (Perkins 6-354) and proceeded to
get a headache!  For naturally aspirated engines, the recommended lubricating
oil is "a reputable brand meeting the minimum requirements of U.S. Military
Specification MIL-L-46152 when a fuel having a maximum sulfer content of 1.3%
by weight is being used".  It "can be identified by API Service Classification
"CC"."  Turbos are referred to MIL-L-2104C, identified by API Service
Classification "CD" unless you wish to reduce your oil change period from 200
to 100 hours, in which case you can revert to the non-turbo spec.'s - my head
is spinning!

Then, under "Viscosity Requirements",  they say temp. range 30 to 80 (F)
should be SAE 20W20 (I guess that means single grade(?)) and, over 80(F)
should be SAE 30.  Has anyone with this engine or similar references
deciphered all of the military idents. above and come up with what they really
want?

Thanks in advance,

Jim

Mar 2008 09:23:54 -0700> CC: trawlers-and-trawlering@lists.samurai.com>
Subject: Re: T&T: Lehman Multigrade v Monograde Oil> > This gets closer to my
question. The "why" of single viscosity oil use.> However, multi viscosity
oils are recommended and used in millions of trucks> and other applications
that would suffer the same degradation yet there does> not seem to be the same
level of debate. Perhaps I just not listening. Also,> does anyone know how
long this supposed process takes before there is a> significant loss of
lubrication. Most of us are changing oil every 100-150> hrs or so. That's not
a long time. And last, it seems that there have been> huge advances in oil
chemistry since our Lehmans were made in the early to mid> 80's. Maybe, there
would be a different recommendation if they were being> made today.> > > Steve
Anderson> > <Multi grade oil has chemicals added to a low viscosity oil that increases its> viscosity. The longer the oil is used, the more they get broken
down and the> lower the viscosity gets until it reaches the viscosity of the
base oil> used.>> _______________________________________________>
http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering> > To
unsubscribe or modify your subscription options (get password, change email
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http://lists.samurai.com/mailman/options/trawlers-and-trawlering> > Trawlers &
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use is prohibited.

Steve Anderson wrote:

I'll refute this statement.  I have one of those "millions" of truck
engines, an older Detroit.  Detroit permits nothing but single-weight
oil, carrying API classification CF-2.  40-wt is preferred, but 30-wt is
permitted in cold climates.  Having done two complete in-frame overhauls
on my Detroit, I am a firm believer in following the factory
recommendation on this.

And, yes, there has been plenty of debate.  You can spend hours and
hours Googling around the internet and turn up tons of discussion on
this (including from many non-believers).  Most tribologists go along
with Detroit's point of view.

I don't know Lehmans, but I am guessing it is much the same logic.
There are no oil company tribologists, AFAIK, that are willing to go out
on a limb and countermand an engine manufacturer's recommendation.

Well, Detroit is still in business, and they still support these older
engines, and they continually publish new recommendations.  They still
mandate use of single-weight in these older engines.

Pain in the butt for us, since no truck stops or express lubes stock the
40-weight any more (very few trucks on the road have engines more than
eight or so years old -- over-the-road trucks put on a quarter million
miles per year, or around 4,000 hours worth.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

Lehman's> designer and probably knows them best.

For my money, if Bob Smith says monograde oil then monograde it is.  End of
discussion.  I find Shell Rotella 30w at one of the newer auto parts chains,
Advanced Auto, I think.  I've been using it since the first Trawlerfest I
attended in '99 and had the good fortune to discover Mr. Smith and his
infinite knowledge of diesel engines.

Regards,

AndyAndy & Linda Woods    Grand Folly    1970 Grand Banks 36 Classic
Crisfield, MD.    grandfolly@hotmail.com