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Way Off Base on Mil Specs

Dear LubesnGreases,

Usually your magazine is very interesting and informative. However, in your May issue I found the article Sunset for MIL Specs completely devoid of factual information regarding military specifications. I find it very disconcerting that you publish articles with very limited and misconstrued information.

First, the MIL-PRF-2104 (as the MIL-L-2104 name referred to in the article has not been in use since 1997) is still the standard military oil, now in version H and soon to be updated to I version. Engine oils under MIL-PRF-2104 are not similar to commercial engine oils as you indicated. How many commercially available engine oils can be utilized in transmissions? The MIL-PRF-2104 requires all qualified oils to meet key transmissions requirements in addition to engine performance tests. The specification utilizes engine tests that have either been developed by ASTM or by the military. The utilization of ASTM test methods by themselves does not make a specification. Reaching the conclusion that because we use standardized ASTM methods it means the products are the same as commercial is not correct. Neither is the assumption that if we follow or implement a commercial practice it means the products are commercial products.

The U.S. Army looks for opportunities to use commercial specifications whenever practical. It also tries to work with SAE or ASTM to create documents that reflect military requirements. The perfect example of what happens when everything works well and industry provides support, is reflected in the success of the SAE J2360 document, for gear lubricants. We funded the conversion of the MIL-PRF-2105 specification to the SAE J2360, and industry fully embraced this. However, other documents (particularly the SAE engine oil specifications) were not successful and have been cancelled as there was very limited commercial support for them.

It is true specifications have been cancelled. However, this has occurred because the military has changed throughout the years. The example provided by the author of MIL-L-46152 is a case in point. This specification was for engine oils used in spark-ignition vehicles. However, since the 1970s the U.S. Army has required new vehicles to be equipped with compression ignition engines and therefore a gasoline engine oil specification was no longer needed.

We continue to support and maintain three key military engine oil specifications. Eventually our goal is to reduce that number to a single specification doing the same work as the three. Logistic footprint reduction, reducing maintenance burden, reducing the soldiers effort to maintain the equipment so equipment is available for action are key drivers for the military when developing and revising military specifications and products. Sunset? No. Lean and stronger, yes.

Luis A. Villahermosa

U.S. Army TARDEC

Warren, Mich.

Ample Credit Due

Your April issue contained a wealth of information that made for very interesting reading. I found the article Why Do Reference Oils Matter? of particular interest due to my past association with the U.S. Army. However, I was very disappointed that the author failed to acknowledge any of the significant work that was done by the Army and the Coordinating Research Council in the development of engine reference oils. The Army-sponsored CRC efforts, in the 1950 to 1970 time frame, were conducted to verify the acceptability of the ASTM Sequence tests for engine oil qualification. This subsequently defined the service language which was then issued by API. For an example, see the CRC Report 393, New Reference Oils for Studying the Oil Oxidation Characteristics of Crankcase Oils in the CLR Oil Test Engine, from June 1966.

Maurice E. Le Pera

Le Pera and Associates

Harrisonburg, Va.

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