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

I don't think there's enough datapoint to draw a conclusion.

That being aside, the benefit of using different brand of oil *pales*
compared to simply adding 30% to your flying frequency. Just fly 30%
more often. You don't even need to fly 30% more hours. Just go out
one *extra* day every week (or two weeks) and fly for half an hour on
top of your existing flying schedule. You'll do better to the engine
than any fancy oil can possibly achieve.

I for one, use the cheap Phillips X/C 20W50, change every 25 hours, and
fly at least twice a week.

Each of us has a hot button, but I'd be willing to bet that one cold
start with marginal preheat would drive the metal analysis way off the
chart. I have no problem with looking for a trend, but consider it for
feedback to your operating guidelines too.

M wrote:

That being aside, the benefit of using different brand of oil *pales*
compared to simply adding 30% to your flying frequency. Just fly 30%
more often. You don't even need to fly 30% more hours. Just go out
one *extra* day every week (or two weeks) and fly for half an hour on
top of your existing flying schedule. You'll do better to the engine
than any fancy oil can possibly achieve.

Thanks, M.

In my case, I fly a minimum of twice per week, every week now for over two
years, as I use my aircraft to commute to my customers' cities of business.
Toss in one Angel Flight every three weeks or so and at least two personal
flights a month, and that brings up the flying total to about 12 legs per
month.

--
Peter

nrp wrote:

Each of us has a hot button, but I'd be willing to bet that one cold
start with marginal preheat would drive the metal analysis way off the
chart. I have no problem with looking for a trend, but consider it for
feedback to your operating guidelines too.

No cold starts here, at least assuming my Tanis heater is working
correctly.

I am religious about plugging in the Tanis heater both at my home T-hangar
and at my destination hangar if temperatures drop below 50 degrees F or so
(this also prevents having to run the engine for a longer than normal time
on the ground to bring the oil temperature up to the minimum of 120 for
takeoff).

When temps fall below 30 degrees F, I throw on the prop and cowling cover
that I purchased a couple of years ago from Kennon in addition to the Tanis
heater.

--
Peter

Congrats! If that's your flying schedule, I don't see any reason why
your engine won't make to the TBO and beyond, regardless of what brand
of oil you use (right viscosity for the temperature of course), as long
as the engine is operated properly. I'm sure most the A&Ps will have
the same opinion about an engine that's flown twice a week.


Peter R. wrote:
In my case, I fly a minimum of twice per week, every week now for over two
years, as I use my aircraft to commute to my customers' cities of business.
Toss in one Angel Flight every three weeks or so and at least two personal
flights a month, and that brings up the flying total to about 12 legs per
month.

--
Peter

M wrote:

Congrats! If that's your flying schedule, I don't see any reason why
your engine won't make to the TBO and beyond, regardless of what brand
of oil you use (right viscosity for the temperature of course), as long
as the engine is operated properly.
snip

You know, I was too quick to post my schedule. In retrospect, there are
normally two weeks off a year due to the aircraft's annual, and in the last
two years I have canceled three times due to weather and once due to
unscheduled maintenance.

Sorry 'bout the overstatement.

--
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.