http://www.shell.com/business-customers ... ation.html
Am I the only one that sees a totally broken page? Links don't link, text missing.
You might want to give a shop that O/H's your engine type a call to see if they can give you an idea as to what's normal, but like I said, normal varies from engine to engine and really, you have to establish "normal" for your own engine.
As mentioned, oil samples are used for trend analysis. Compare each sample with the previous one to see an abnormal spike in any of the metallic particles to see what's breaking down.
You can order a pre-paid kit. Fill out the info for the engine or component, they send you the results.
The second overhaul was due to cracks in the case which would not have shown up in the oil analysis.
So at least in my case, for the two overhauls I've had, the oil analysis was unnecessary and frankly just increased my stress level unnecessarily. The engine gave plenty of other warnings.
Perhaps with other failure modes its more helpful, I don't know, perhaps bronze bushing material tells you of impending crank bushing or con rod bushing failures but very high oil temperatures and lowered pressure are also good indicators of bushing problems.
Anyway currently I'm not doing them.
I'm with helicopterray. It's more about the trends than anything. Mine for example shows slightly abnormal nickel levels which is indicative of valve wear. It is a trend I have been following for 3 years now. Talking with other identical engine owners, they're seeing similar numbers and getting TBO and higher without issues. Cutting open the filters is just as important. It gives you a trend as well.
Actually every time I do an oil change I drain my oil into a funnel with a fine metal screen to see what came out, and of course I check the oil screen upper and lower.
IMHO you should always be cutting open the oil filter after oil changes and also draining the oil through a screen not just directly into a bucket. Oil analysis is not a substitute for checking the filters because you won't necessarily see increased metal in the oil analysis when a chunk breaks free and gets stuck in the filter!
Recirculating Lubrication Systems Package – ICP Metal Scan, Viscosities at 40⁰C and 100⁰C, Visual Inspection, Oxidation/Nitration/Sulfation (Infrared Scan), Moisture by Karl Fischer (If Crackle Test for Water is Positive), Total Acid Number, ISO Particle Count
Complete Analysis Package - ICP Metal Scan, Viscosities at 40C and 100C, Visual Inspection, Oxidation/Nitration/Sulfation/Soot (Full Infrared Scan), Crackle
Test for Water, Fuel % by Gas Chromatography (If Fuel Dilution is Suspected), TBN and TAN, Iso Particle Count or Patch Test
On general principle I was going to ignore the complete analysis package which leaves me with the choice of spending an extra $14 on Total Acid Number and ISO Particle Count. No idea what the ISO Particle Count is unless it's something about not freaking out the border gaurds with nuclear bomb detectors when I'm clearing customs. I like the idea of getting a reading on the acid number as the plane is parked outside and I only do an oil change every 4 months. Does anyone else doing oil analysis do an acid test? Ever seen worrying numbers? I'm considering doing the acid test for the first 3 samples and if everything looks good dropping it in the future.Basic Wear Package - ICP Metal Scan, Viscosities at 40C and 100C, Visual Inspection, Oxidation/Nitration/Sulfation/Soot (Full Infrared Scan), Crackle Test for Water, Fuel % by Gas Chromatography (If Fuel Dilution is Suspected)
Wow. I really hate the quotes on this new forum format.
All that other stuff seems like marketing propaganda to me. ISO Particle Count? Crackle test for water? Gas Chromatography? I have never even thought about those things when trending GA recip engines.