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Read our primer articles on Oil Analysis and Tribology

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To be honest, most figures generated by OEM's do not accurately represent target cleanliness levels for most equipment. You should set your own targets in relation to contamination dependant on machine criticality, environment in which it is used and other factors that may effect its operation. There is no point in maintaining an extremely clean system if it costs more in filtration then if you actually had a breakdown, so be sure to not overshoot the mark by too much. In all, it may pay to hire a professional to help you achieve the required balance.
On another note, the only reason I would recommend this over OEM recommendations would be because I have seen some rather odd figures from CAT. Hands up from anyone who agrees with a 20/17 being an exceptable limit for a machine with servo valves?
A word of caution to anyone starting to build alarms for Caterpillar equipment, size does matter. In larger Caterpillar engines the wear metals are above the 2-4 micron size that a typical lab tests. On a similar note, know what your lab is telling you. The different lab test and equipment will give you different results. While most labs will give you the same baseline the results but the difference between 2, 4, 6, 8 microns and up to 100 micron can be the difference of an engine block or not. In the end there is no substitute for trend data from your fleet with your own duty cycles and consistent lab data.
Thanks for all.
I was visit Caterpillar website and I saw the table that show alarm limits for Caterpillar Engines. But this table not shows Alarm Limits for Wear Metals. I was find these Limits on website of National Tribology Services (www.natrib.com/appnotes.htm)
These Limits are following:
Oil Analysis Test Caterpillar(all models) Cummins(all models) Detroit Diesel(all models)
Spectroscopy, Iron 100 ppm 84 ppm 150 ppm
Spectroscopy, Copper 45 ppm 20 ppm 90 ppm
Spectroscopy, Lead 100 ppm 100 ppm none specified
Spectroscopy, Aluminium 15 ppm 15 ppm none specified
Spectroscopy, Chromium 15 ppm 15 ppm none specified
Spectroscopy, Tin 20 ppm 20 ppm none specified
Spectroscopy, Sodium 40 ppm 20 ppm 50 ppm
Spectroscopy, Boron 20 ppm 25 ppm 20 ppm
Spectroscopy, Silicon 10 ppm 15 ppm none specified
Viscosity +20 % to -10 % of nominal SAE grade +/- 1 SAE grade or 4 Cst from new oil (Visc @ 100 ° C) +40 % to -15% of nominal grade (Visc @ 40 ° C)
Water 0.25% max 0.2% max. 0.3% max
TBN 1.0 mg KOH/g min value 2.0 mg KOH/g min., or one-half of new oil value, or equal to TAN 1.0 mg KOH/g min value
Fuel Dilution 5% max. 5% max 2.5% max
Glycol Dilution 0.1% max 0.1% max 0.1% max.
Ferrography on exceptions on exceptions on exceptions

May be it will be useful for anyone.
Mikhail,

Interpretation is not just comparing wear limits.Wear limits established by OEM's is
statisticaly derived,and should be used as
guidelines only.Alarm limits has to be established by trending approach,correlating
field report with oil analysis reports.

Trend can be established by analysing three samples at regular intervals.Any gross deviation from baseline signals problems.
There are several factors which affect wear
of engines.Overloading,Overspeeding,High operating temperatures,Environment,Operating
practices,Lubricant properties,contamination,
sampling procedures...all affect wear datas.

When data reaches moderate level,sampling intervals has to be cut shortened,engine performance tests has to be carried out.

Nevertear down engine based on single sample analysis.Several customers burnt their fingers
by wrong conclusions.

Worldwide cat dealers has excellent product support lab to help your needs.


Bala.
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