[JYO] Important info for Exxon Elite Users...

There was an article about Exxon Elite in Aviation Consumer that was posted 
on a DC Pilot message board.  Since I am an Exxon Elite User, I wrote to my 
contacts at Exxon for a reply. The original post is at the very bottom of 
this message.

Ed

- - - -
Ed,

As AC indicated in their article we were notified of the article, though we 
did not see the complete article until yesterday.  The damaging remarks deal 
with wear testing, so we have been carefully analyzing what AC did.

Of course, they have positioned themselves as the industry champion; 
therefore, almost any comment we make will appear to be self serving.

The bottom line, I think, is that if you manufacture a product people will 
take pot shots at you.  All I can offer is a scientific, unemotional review 
of their testing and let consumers decide if what AC did was reasonable, or 
if other wear test provide a more accurate ranking of products in terms of 
wear protection.

In this case, AC is providing misleading information.  Please feel free to 
post this message and my comments below freely.  This response will appear in 
AC next month.  I provide a summary and then a detailed discussion.

============================================================

We were surprised by Aviation Consumer's test results, so we ran the same 
test (ASTM D 2670) under the same modified conditions, at two different, 
independent laboratories.  Both independent labs reported that Exxon Elite, 
after multiple runs through the test, is capable of holding load and running 
to completion, though admittedly with higher wear rates than some ther 
products.  Nevertheless, comparing aviation piston oils using the Aviation 
Consumer test method is like saying that Tiger Woods isn't a good golfer 
because you once saw him misplay a bridge hand.

Several observations would support our conclusion:

Summary

-  The Falex Pin and Vee Block Test (ASTM D 2670) is normally used to 
evaluate the wear properties of heavy-duty gear oils.

-  The lubricating conditions of the instrument (speed, load, and contact 
geometry) make it unsuitable to reproduce the conditions of piston engine 
valve trains.

-   As proof, no aviation piston engine oil can carry the load specified in 
the standard ASTM D 2670 test, so Aviation Consumer had to modify the test 
procedure.

-  However, no correlation exists between the results of the modified 
Aviation Consumer test and actual camshaft wear in aviation piston engines 
because oil type and contact loads were changed from the Phillips Petroleum 
paper referenced by Aviation Consumer.

-  Additionally, in order to complete the test in 3.5 hours, Aviation 
Consumer had to test under enormous loads and at very low speed.  This 
changes the lubrication regime possibly resulting in a false rankings of 
oils.

Detailed Discussion

The Falex Pin and Vee Block Test (ASTM D 2670) is normally used to evaluate 
the wear properties of heavy-duty gear oils.  The lubricating conditions of 
the instrument (speed, load, and contact geometry) make it unsuitable to 
reproduce the conditions of piston engine valve trains.  No aviation piston 
engine oil can carry the load specified in the standard ASTM D 2670 test.

Aviation Consumer provided a reference paper where the test conditions were 
modified and a correlation with a stationary automotive engine test was 
developed; however, correlative tests are not the same thing as simulative 
tests.  In the reference paper, the test was shown to rank the oils in a 
similar way as the engine test results on the same oils.   However, all these 
oils contained various zinc dialkyl dithiophosphate additives, which are 
ash-forming and cannot be used in aviation piston engine oils.  Once you 
change the type of oils from which the correlation was developed, there is no 
reason to expect the correlation to hold.

The Aviation Consumer version of this test is yet again different from the 
method described in the reference paper, in that it utilized higher contact 
loads; therefore, there is no reason to expect the correlation to hold.

We chose to use the Motor Industry Research Association (MIRA) test in wear 
evaluations because it offers a much closer simulation of the conditions in a 
Lycoming TIO-540-J2BD engine valve train.   It uses actual engine parts 
rather than the test parts of different geometry and metallurgy used in the 
Falex test.

Rotation is conducted at typical camshaft speeds (1250 rpm) rather than the 
290-rpm used by Aviation Consumer.  After break-in, we operated our rig at 
elevated temperature (240 deg F), and overloaded the spring pressure on the 
follower (raised it from the normal 195 lbs to 292 lbs) so that the test 
duration could be reduced from a couple of thousand of hours (normal TBO) to 
about 300 hours.  The equivalent load used in the Aviation Consumer method is 
500 lbs, which is enormous.

The price you pay for completing a test in 3.5 hours in the Falex Pin and Vee 
Block Machine is that you have to run under conditions of high load and low 
speed, and it is well known by tribologists that this changes the lubrication 
regime and may rank oils differently.

While we are happy to confirm that, contrary to Aviation Consumer's test 
results, Exxon Elite can complete the modified ASTM D 2670 test, we choose to 
rely on other tests, such as the MIRA test, to provide a more relevant 
measure of an aviation piston engine oil's performance.

Tests such as the MIRA employ the same strategy of accelerated testing by 
overloading specimens, but use materials and parts actually found in aviation 
piston engines and run under lubrication, loading and contact geometry 
conditions much closer to the actual operating conditions found in these 
engines. MIRA shows that Exxon Elite 20W-50 is the only commercially 
available multigrade that can run to completion with no surface deformation 
on either the cam lobe or follower.

Product performance testing is useful to consumers to the extent that it 
provides an accurate ranking of the products tested. However, we think that 
neither the rust testing nor the wear testing conducted by Aviation Consumer 
results in such an accurate comparison.  Rather, the results presented may 
actually inadvertently mislead aircraft owners regarding
in-use performance of oils.
                                                                              
                                   
 
- - -


To: "'dcpilots-l@xxxxxxx'" <dcpilots-l@xxxxxxx>
Subject: [DCPILOTS] Exxon Elite
From: "Boggs, William" <William.Boggs@xxxxxxxxx>
Date: Wed, 18 Sep 2002 16:28:30 -0400
Reply-to: dcpilots-l@xxxxxxx
Sender: owner-dcpilots-l@xxxxxxxxxxxxx I know several of you have begun
using Exxon Elite and wanted to see what
folks thought of the product in light of the recent Aviation Consumer
article.

I was truly suprised to hear that Elite failed Aviation consumers
acclerated
wear tests.  They acknowledged these tests exceeded the pressures commonly
found in aviation engines, but to me it seems like an area were "more is
better".  They did say corrosion was more of a problem that wear for most
operators, and that Elite had impressive anti-corrosion properties.
However, in the end, they seemed to lean strongly towards using Aeroshell
and doing more frequent changes to address the corrosion issue.

I recently purchased a case of Elite and found it took some effort to find
locally and was a good deal more expensive than the easily available
Aeroshell.  Given those issues, and the new information from Av Con,  I'm
second guessing that purchase now and wondering if I should stick with
Aeroshell.

I posted this query on another group I post to, and got a lot of response
from the "stick with Aeroshell" crowd but didn't get much from the Elite
users.

Are any of you Elite user planning to switch back based on the recent
Aviation Consumer report?

I'm doing an oil change on Friday and so I'd appreciate any input.

Bill Boggs
Tiger N28815

PS if I go with Aeroshell is anyone interested in a case of Elite?

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