Machinery Lubrication

Machinery Lubrication September October

Machinery Lubrication magazine published by Noria Corporation

Issue link: http://www.e-digitaleditions.com/i/730290

Contents of this Issue

Navigation

Page 49 of 69

the intake air filter or the oil filter. For example, if the oil filter has ruptured, it may not be removing contaminants sufficiently, allowing them to become continually ingressed into the engine oil. Water Water content is generally determined using the Karl Fischer test, which reports the amount of water present in oil in parts per million. An oil sample may also be screened first through a crackle test. Water in oil is particularly concerning because it can lead to rapid oil degradation and a corrosive reaction to iron and steel mechanical surfaces. The source of water must be investigated if abnormal amounts are found. These sources could include leaks from the oil cooler, high levels of moisture in the environment or ineffi - cient running conditions. Ferrous Density This test focuses on increased levels of ferrous wear particles present in the oil sample. Once wear debris is observed at abnormal levels, remediation actions must be taken seriously, as the potential for engine failure is impending. Unlike solid contami - nants and moisture, which are root causes that could lead to failure, increased levels of wear debris indicate that mechanical wear is already occurring in the engine. This may be a consequence of inaction to the contamina- tion levels or poor lubrication due to changes in oil properties. It could also be a result of changes in operating conditions or mechan- ical inefficiencies. Analytical Ferrography If wear debris has been observed at abnormal levels, additional techniques can be used to examine it more closely to obtain clues as to its severity and root cause. This micro- scopic review of wear debris particles includes characterizing the general shape, size, color, reflectivity, edge details, markings and concen - trations. The results can help establish from which components the wear particle originated and by which wear mode the particle was produced. These details can be useful in under - standing how severe the problem is and if remediation actions are required. The patch test is a similar method used to obser ve insoluble deposits on a porous membrane through which oil has been pulled. It offers a means of analyzing concen - trated amounts of contaminants or oil degradation byproducts. Fourier Transform Infrared (FTIR) Spectroscopy This test provides information about not only the oil's health but also contaminants like soot, water, glycol and fuel, as well as oil degradation byproducts such as oxides, nitrates and sulfates. It employs a unique technology that observes constituents within the sample at the molecular level. While the test excels in its capability to review a broad spectrum for analysis, its accuracy can be somewhat limited. Elemental Spectroscopy Elemental spectroscopy is similar to FTIR, but instead of observing constituents at the molecular level, it is able to report details about the oil at the elemental level. The results are most valuable after they have been trended with a reference sample or a history of samples from the same engine. As elemental concentra - tions increase or decrease, the trends can be correlated to specific wear patterns, contami- nation level increases or a depletion in additives formulated within the oil. Other possible tests include flash point, fuel dilution, acid number, optical soot meters and blotter spot testing. The exact combination of tests to perform will depend on the types of questions you need answered. Whether you are a hot-rod owner who can't bear the thought of an engine failure or a casual vehicle owner who doesn't want to be inconvenienced by a breakdown, there are good reasons to perform oil analysis. The oil in your engine is full of details, and it's just waiting to give you an update on how the engine is doing. So the next time you change your oil, consider taking a sample and having it tested. Reference Fitch, J.C. (2012). Analysis of In-Service Automotive Engine Oils. S.C. Tung & G.E. Totten (Eds.), Automotive Lubricants and Testing. About the Author Bennett Fitch is a senior technical consultant with Noria Corporation. He is a mechanical engineer who holds a Machine Lubricant Analyst (ML A) Level III certification and a Machine Lubrication Technician (MLT) Level II certification through the International Council for Machinery Lubrication (ICML). Contact Bennett at bfitch@noria.com. ML Oil analysis can be beneficial to most owners and drivers of passenger vehicles if the right information is obtained.

Articles in this issue

Links on this page

Archives of this issue

view archives of Machinery Lubrication - Machinery Lubrication September October