Exxon Elite Oil: More favorable oil analysis or simply coincidence?

With my rebuilt Bonanza engine, I have been faithfully sending in every oil
sample drawn from the 40-50 hour oil change to Aviation Laboratories for an
oil sample.

When I receive the report from the lab, I log it to an MS Excel spreadsheet
in order to catch any trends. Currently I have seven oil analyses logged
over the 300 hours that this engine has on it.

Normally I use Aeroshell Multigrade 15w50, but last winter I used Exxon
Elite 20w50 for one of the oil changes under the assumption that it would
combat corrosion that might occur from condensation build-up in the oil
after engine-shutdown.

An interesting data point has emerged that has me curious. All of the
metals discovered in the oil analysis after using Exxon Elite were of
significantly lower quantities when compared to the analyses from the
Aeroshell multigrade, either before or after the use of the Exxon Elite.

Is this just coincidence or does this indicate that perhaps Exxon Elite
does provide better engine lubrication?

My aircraft is a few hours away from an oil change and, as we approach
winter in the Northeast, I am considering using Exxon Elite again.

--
Peter

Pete, I don't want this to come across as condescending but you have a
graph to look for trends and then you focus on a single point of data
that is off the trend line ?!?

denny

Denny wrote:

Pete, I don't want this to come across as condescending but you have a
graph to look for trends and then you focus on a single point of data
that is off the trend line ?!?

Denny, with only 8 data points in about 300 hours of operation time, there
is not much of a trend for this engine yet. I like to think of it as a
baseline, where unfavorable deviations (when something goes wrong) will
stand out noticeably. Honestly, I wasn't expecting this exercise to
produce anything positive.

I am not meaning to come off as condescending either, but have you ever
paid for the cost of a rebuilt or new engine and the installation of this
engine into an aircraft? If so, then you will certainly respect my
attempt at maintaining this engine to the absolute best of my ability.
Given the cost of this endeavor, my desire is to be able to take this
engine well past TBO.

If this attempt includes spotting a favorable deviation in data early (and
I am talking about one obviously lower point out of only eight data points,
not one out of a hundred), then I am certainly willing to explore this
further. Hence the topic in an aircraft owners' newsgroup, where other,
more experienced owners could perhaps substantiate or refute this theory.


--
Peter

Peter R. wrote:
Pete, I don't want this to come across as condescending but you have a
graph to look for trends and then you focus on a single point of data
that is off the trend line ?!?

Interesting point. I had my case split and cam replaced based on 1
unfavorable analysis.

Denny, with only 8 data points in about 300 hours of operation time, there
is not much of a trend for this engine yet. I like to think of it as a
baseline, where unfavorable deviations (when something goes wrong) will
stand out noticeably. Honestly, I wasn't expecting this exercise to
produce anything positive.

I am not meaning to come off as condescending either, but have you ever
paid for the cost of a rebuilt or new engine and the installation of this
engine into an aircraft? If so, then you will certainly respect my
attempt at maintaining this engine to the absolute best of my ability.
Given the cost of this endeavor, my desire is to be able to take this
engine well past TBO.

How unfavorable was the single analysis, hmmm?
denny
Maule Driver wrote:

Interesting point. I had my case split and cam replaced based on 1
unfavorable analysis.

Denny wrote:
How unfavorable was the single analysis, hmmm?
denny
Maule Driver wrote:

Interesting point. I had my case split and cam replaced based on 1
unfavorable analysis.


What do you think?

I had a string of 14 previous samples on my Lycoming 360 from 35hrs TT
to 1146hrs.

I would get an iron reading of '25.0' for about 35 hours of operation
throughout this period of 7 years.

On the 15 sample I got an iron reading of '101.0' for 36 hours of
operation since last analysis.

A subsequent filter analysis did show some very fine iron filings. The
filings felt like fine silt to the touch. No chunks or sand size particles.

Asked around for input (including here). In the end, it was clear
'something' had begun to happen. Everything else checkable, checked out
ok. I planned to keep flying this aircraft for at least 3 more years.

I had it split. There were indications that 2 lobs on the cam had just
begun to spall.

Pete, I have no criticism of your determination to maximize engine
longevity... I have a pair of engines I'm babying along...
Yes, I have rebuilt aircraft engines sob, sob...
Let me play devils advocate here based on the additional information
you have given to other posters..
1. you run the engine regularily..
2. you preheat in cold temps...
So, let me be the first to say you are wasting your money on
semisynthetic, multiviscosity oils! Yes, wasting your money, kemo
sabe...
You should be using a good, single viscosity oil, changing the oil
religously at 25 hours, and your filter at 50 or 75 hours... Having
that bright, golden, fresh, slippery, oil in the engine will do more to
prevent wear than anything else you can do...
Every branded oil company has an excellent, single viscosity, petroleum
based oil, with Lycoming additive that they can barely give away... An
industry secret that FBO's know... Let me suggest Phillips 100AW at
less than half the price of 15W50, or 20W50 as a good oil to use...

Now, this advice does not apply to engines that routinely go weeks
between starts, that are started stone cold, etc.. There a
semisynthetic, multiviscosity oil is probably the best - actually a new
owner that runs them often is the best, but it's an imperfect world...

The other habit I would forego is ground running... More engines than
you can wave a stick at are burnt' up getting the oil temp "into the
green"... By the time you run up and taxi to the runway that engine
is ready to go..

The last comment I will make on this is that changing oil brand/type is
guaranteed to obscure the analysis for 2 to 4 changes...
No, I don't do oil analysis... I change my own oil, I cut open my own
filters, i clean my own plugs, and I listen to my engines... Not
perfect, but it's an imperffff, uhh, geez the echo in here is
deafening...

denny

Denny wrote:

The other habit I would forego is ground running... More engines than
you can wave a stick at are burnt' up getting the oil temp "into the
green"... By the time you run up and taxi to the runway that engine
is ready to go..

Thanks, Denny. I will seriously consider your advice about the oil type.
The advice above I am not sure I agree with, however. My Bonanza is
equipped with a turbo-normalized IO-520, something I may have failed to
mention earlier.

If the oil is not warm enough, the engine will most definitely overboost
two inches or more of MP.

--
Peter

Peter R. wrote:

If the oil is not warm enough, the engine will most definitely overboost
two inches or more of MP.

Hi Peter, with apologies for the tangent from the original topic: would you mind
briefly educating us (well, me) about how low oil temperature leads to overboost?

Thanks.

"Peter R." wrote in message
...
Denny wrote:

The other habit I would forego is ground running... More engines than
you can wave a stick at are burnt' up getting the oil temp "into the
green"... By the time you run up and taxi to the runway that engine
is ready to go..

Thanks, Denny. I will seriously consider your advice about the oil type.
The advice above I am not sure I agree with, however. My Bonanza is
equipped with a turbo-normalized IO-520, something I may have failed to
mention earlier.

If the oil is not warm enough, the engine will most definitely overboost
two inches or more of MP.

A good summation he http://www.avweb.com/news/columns/186619-1.html

Is this what Denny is referring to about "burning up the engine"? With a
TN'ed engine, it's even more critical.


--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)