Don Robertson's Marine Marketplace


The following two articles are reprinted from the Spring 2001 edition of the Society of Accredited Marine Surveyors newsletter, with permission of the authors.


Did you catch a good sample?
by Floyd J. Friloux, SAMS® Affiliate Member


Oil Analysis Customers sometimes express aggravation with laboratories that ask this question when they first deliver a sample of lube oil or fuel for analysis.

As a working relationship is established with a surveyor and their expectations are understood, this question is answered without our need to ask.

In seventeen years we have learned to be a little more sensitive to the needs of surveyors.  It quickly becomes apparent that you can't tell someone:

  • "If you can't start the engine you might as well not bother to sample it"
  • "We couldn't make an evaluation since you didn't show how long oil was in use."
  • "The engine has to be run at least 20 hours before any evaluation is possible."
  • "If the sample wasn't labeled legibly we probably threw it out."
It is important that a lab try to understand the difficulties encountered as a surveyor.  Likewise, the surveyor must understand that the results and evaluation developed from an analysis are entirely related to the type of sample that was possible.

While willing to test a few ounces of oil drained from a failed engine that hasn't run in weeks, it must be understood that analysis might only be of value to detect gross contamination or degradation.

A true wear evaluation cannot be expected in this situation.  Sampling and analyses often require compromises in methods, acceptable conditions, and expectations.

I have attempted to describe a sampling method for the perfect world where equipment is clean, able to be run to operating temperature, and proper sampling supplies are available.

Real World situations are then accepted and possible compromises in Sample procedures are then proposed with the limitations explained.

ENGINE OIL PREPARATION

Check oil levels, identify type of oil, record how long oil has been in use, perform sea trial or run engine under load for several minutes after reaching operating temperature.

SAMPLING

Several good methods are available for owners to prepare a convenient method of collecting used oil samples from engine, but for a surveyor that seldom has a chance to see the engine before the inspection job, we offer these suggestions:

Small manual or battery powered vacuum pumps are available that can use ¼" inch polyethylene tubing, readily available as icemaker hose, to draw oil samples from dipstick opening.  Many oil-testing services provide pre cut lengths of the tubing for each sample bottle.

Some surveyors prefer to carry uncut rolls of the tubing, which they insert into dipstick and cut to desired length.

Tubing should allow pump to be operated comfortably while keeping sample container upright.  When sampled hot, immediately after operation, end of tubing should be approximately one inch from bottom of oil pan.

The sampler end of tube should project only slightly into bottle and is less messy if flow of oil sample stops before reaching the tube.

When a four-ounce bottle is used the three ounces needed for full analysis, under most circumstances, leaves plenty of extra room.

Oil Analysis Suggestion: Make note whether the tubing is covered with rust, sludge, or film of oil when pulled from dipstick.  This gives an indication of condensation collecting in tube, possibly from infrequent use, or short runs at dock insufficient to drive off water collecting in cold engine at start up.

A large plastic syringe, available from many pharmacies, can also be used in the same manner with smaller diameter tubing.

Sampled oil can be dispensed into bottle for shipment or some large syringes make provisions for detaching plunger rod and sealing tip for shipment in the syringe.

When a sample of oil is necessary from an engine that cannot or should not be started, sample should be marked accordingly.

Advise lab if sample is drawn directly off the bottom to identity settled wear solids, which will obviously exaggerate wear and contamination levels, or up an inch from the bottom in order to catch a cleaner sample for easier check of most physical characteristics of oil.  If oil has been previously drained a sample, admittedly of limited value, might be available from filter.

Suggestion: When sampling a cold engine, coolant or raw water entry might be detected by a layer of water found below level of the oil, since the water has a higher density.  Water entry after failure is usually apparent as free water under relatively dry lube.

Water entry during operation will normally cause a bottom emulsion layer with higher than typical amount of suspended water in the oil.  Water entry after failure can often be confirmed by oil in filter containing minimal water concentration.

TRANSMISSION/REDUCTION GEAR OIL


PREPARATION - Basically the same as for engines.  Check the fluid levels and warm up by engaging gears, forward and reverse.  In some cases a fine screen is present to collect larger solids in the fluid stream.  When time allows, a check of the screen both before and after sea trial might be considered for comparison.

SUMMARY


Oil analysis is best used as a trending tool to compare changes from one sample to another on the same piece of equipment.

Your lube analysts need all the available info you can supply to evaluate condition on a single sample with no prior history.

Human nature causes laboratory personnel to spend more time in sample review if there is more sample information influencing the final evaluation

Next time: Should I sample the fuel and coolant tanks?

Floyd J. Friloux of Lubriport Laboratories, SAMS® Affiliate Member
1650 Airline Highway
Kenner, Louisiana 70062
504-577-7492-O, 504 464-1292-Fax
ffriloux@lubriport.com

 








Oil sampling - One surveyor's notes by James G. Merritt, SAMS® AMS®

Oil Analysis


The companion article to these notes (on page 12) was written by one of our SAMS® Affiliate Members, Floyd Friloux of Lubri-Port Laboratories, Kenner, LA.

Floyd has a great deal of experience in this field and graciously consented to preparing the article after being harassed for a couple of years to get some basic procedures on paper.

As with all things in the surveying profession no two circumstances are exactly the same, there are always other factors that affect what is needed or practical in each situation.

When should oil sampling be recommended?  I offer it as an additional cost item on all surveys and strongly recommend it on all high dollar engines - diesels over 70 horsepower and "go-fast" gas engines.  Other tests are also normally recommended on these engines to help assure the buyer/owner the engines are fully checked and, hopefully, will give good service.

Standard series engines that are readily replaceable with marine rebuilt units are not given the same attention unless the sea trial is not satisfactory.  Pure economics and time constraints are the real determinants.

Drawing the samples - I use a 60cc syringe (approx. 2 oz.) and ¼" polyethylene tubing cut to a length about two inches longer than the dipstick.  A fresh syringe and new tube is used on each sample to minimize the possibility of contamination between samples.  The lab furnishes the sample bottles, the tubing is about 10 cents per foot, and the syringes are less than a dollar apiece at veterinary supply stores.  All relatively inexpensive with no mess to clean up or store after the job is done.

Oil Samples The lab needs about 3 oz. of liquid to work with as this gives them enough for a full sample plus a reserve for retest if anything goes wrong or looks suspicious on the first test.

Most of the major diesel engine companies offer sample withdrawal kits and analysis by their laboratories as a part of after sale services.  If you do a lot of a survey work on a particular brand of engine you may want to use this approach as they will have a large database that is product specific.

Engines that warrant oil sampling and have closed cooling systems also get the coolant sampled as part of the process.  Large diesels in particular can develop major problems with potential loss of the engine due to the wrong coolant or contaminated coolant.

A one-time sample does not give a trend but it can be a very valuable tool in the surveying process.

A single blood test may not reveal a heart problem, but if it shows you have Hepatitis, corrective action is needed immediately!

James G. Merritt - SAMS® Accredited Marine Surveyor 1992
Tangent Development Co., Marine Division
1715 Harlequin Run
Austin, Texas 78758
512-837-9170-O, 512-835-9629-Fax
survrjim@austin.rr.com



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