testing oil samples

[facthunter]

On the Farm..... Dad, where does steel wool come from? Dunno Son, I suppose they get it off them hydraulic rams. Nev

 

 

[old man emu]

That $35 Australian price seems pretty good. I looked at a price for it in the USA and it was $US28.

 

Vev said, "However in the context of the type engines and flying we do, I think it's an over kill and almost behind the curve as we change our oil at 25 or 50 hour intervals and should also be changing our oil filters too.", and I think that pretty well sums it up. Often regular, careful inspection using the Eyeball Mark 1 device is suffifient.

 

OME

 

 

[facthunter]

Yeah but the equipment the pros do it with probably costs tens of thousands in a laboratory where they specialise in analysis spectroscopically and digitally.

 

Anyhow when it comes to things about oil and fuels, I listen to Vev. It's his game all that stuff, but he doesn't blow his own trumpet much. Nev

 

 

[Yenn]

With an engine that is several years old and only done a few hours I would say oil analysis would be a good thing.

 

What kills engines is corrosion and wear. The wear will show up in oil analysis and what elemant is increasing points where to look. Copper rising, possibly bearing metal, iron, possibly camshaft. Whereas silicon rising points to a faulty air cleaner.

 

The other diagnostics are the pull through before starting, that will show sudden ring sticking or valve seating problems. Leak down test is probably the best of all giving a good idea of the combustion area condition. Then EGT can show combustion conditions as they occur, faulty plugs or leaking manifold and CHT can show how hard the engine is working and how the mixture is for that power.

 

In short oil analysis is just another tool in our efforts to keep the engine running well. If you don't know how to use the tools you need advice from someone who does.

 

 

[Oscar]

I am of a 'halfway house' mind on oil testing. If one has an engine one knows very well, with reliable monitoring of the critical factors (cht, egt), and is sensitive to things like the pull-through variation and does regular filter inspections at every oil change, I think it is unnecessary to progress beyond the old 'Eyeball Mk.1' unless said eyeball detects something unusual.

 

If I am not mistaken, oil sample testing is most usually used as a predictive measure of maintenance requirements. Any sample analysis requires interpretation of the results with knowledge of the engine ( or, for that matter, gearbox etc.) from which the oil sample was obtained. If you are NOT technically familiar with extrapolating the oil sample report to understanding what has been going on in the component from which the sample was taken - it is no use to you to do it.

 

The oil sample report does NOT come with ( in my experience) any statement of 'this is what is happening inside your [engine, gearbox, hydraulic motor etc.]. It's simply a statement of what was in the oil tested.

 

Examination of the filter at every oil change, will tell pretty much anybody with a decent Eyeball Mk. I if there are suddenly bits of rings, pistons, large amounts of bearing metal etc. present. The Eyeball Mk.I is a somewhat coarse instrument, but valuable for early detection of impending failure, but it is equally not much damn good at detecting fine differences.

 

It's a bit like 'holistic' blood tests for 'wellness': meaningless unless you have the diagnostic skills to correlate the results with the causes. As has been bought out on this thread: for the more sophisticated devices maintained by more sophisticated personnel, an oil test is simply a part of gathering information to be used to evaluate the 'health' of components. If you do not have - or utilise - the skills to extrapolate conclusions from the oil test reports: then they are of no use to you.

 

 

[facthunter]

As often as not it's used to confirm the appropriateness of, or extend further the oil drain periods of long haul vehicles. ED oils have additives which counteract certain chemical contaminants and the additives can wear out. All additives are something other than oil, but they do a job for certain specific applications.. Nev

 

 

[jetjr]

You do get good analysis of results but only on well known engines

 

Report can say whats wearing and whats typical for that model, hrs and application

 

Problem is its very unlikely this info exists for small areo engines so youll just get a list of what testing finds

 

 

[dlegg]

How often do you guys think a Jab 3300 needs its oil changed if it only uses Premium 98 and averages 150hrs per year? 25 hr changes seems a bit too much.

 

 

[facthunter]

Really it depends on dust exposure and what type of trips you do. If you only do a few circuits or short trips that's not ideal. Runs of over an hour makes sure it's all up to temperature. Oil doesn't wear out but it's not that expensive either. Nev

 

 

[Kamloops]

I change the oil im my plane every 50 hours approximately.

 

Versus my vehi les that an easily accumulate 300 to 400 hours between changes?

 

I see no reason why I would ever get my oil tested.

 

But for some it may make them feel all warm and fuzzy inside.

 

 

[Oscar]

The CAMit TOCA ( Thermostat Oil Cooler Adaptor) is a really worthwhile addition to your Jab. or CAE engine, (if you have a 19-reg or E-LSA reg one, anyway). http://camitaeroengines.net/products/toca Not only does it ensure that your oil is not overcooled, but as a side benefit, you don't have to sit quietly heating up the heads too much while waiting for the OT to come up, thus taking off with an engine that has possibly some very hot heads if you haven't been able to get the thing pointed accurately into wind while doing the run up, but it incorporates the CAMit improved oil pressure relief valve. AND, you don't have to blank off part of your oil cooler for colder weather operation...

 

 

[DrZoos]

I would spend every spare dollar on fuel to fly, beer to talk about it and whats left over go buy your mrs a rose for some understanding...

 

 

[Yenn]

Think about what your engines usual failure modes are and then, can oil show what is happening with those modes.

 

It is unlikely to show much with broken through bolts, or cracked heads. On the other hand with piston and ring wear there would be elevated iron and aluminium, valve guide wear may show up as copper, zinc, tin etc.

 

I run a Lycoming which has the camshaft above the crankshaft and is known to have camshaft spalling issues. Oil analysis could show this starting to happen, by iron or possibly chromium rising. Jabiru also has a high camshaft, but I don't think camshaft wear is a major problem.

 

I am not using oil analisis as the Lycoming has less than 100 hours on it so far. Maybe I will go that way in the future.

 

 

[jetjr]

This is the type of info you can get from heavy machinery analysis on known engines

 

Very important the composition and source is correct for your engine type

 

 

[Oscar]

Aha, JJ, are you referring to a service provided by an equipment vendor as part of a 'maintenance contract', or 'after-sales service' type of arrangement? I'd imagine that where a specific manufacturer has a database of 'typical' condition, and/or keeps historical records of your specific piece of equipment, then for sure they'd be able to provide an authoritative report and opinion on how your particular item is travelling viz. the 'norm'.

 

For us 'blow-in' types who are simply using the oil analysis service as a basically one-off analysis of what's in the sample, it's mostly going to be back on us to interpret the analysis report. However, maybe if we pass the results back to the manufacturer (e.g. Jabiru / CAMit / Rotax etc.) for comment, then they can - if they don't already do this - build up such a database which would allow them to make informed comment. AFAIK, that's planned for the CAMit engine test runs, and I would be pretty sure Ian Bent would welcome any such feedback from his CAE engine users.

 

Which brings us to an interesting, and potentially useful point. For such a database to be of real utility, it would be very helpful if a bit more than just the engine number etc. was recorded: since there is such variation between types of usage, fuel used etc, it would be of great value if such details are reasonably faithfully recorded ( and a recorded history from an EMIS would be terrific for that.)

 

 

[cooperplace]

Inadvertently there was shown a situation where the old neoprene washer stayed with the engine. Had that not been detected the oil pressure would have forced the extra washer out and the engine would have lost the oil very quickly and failed in no time flat. One washer is backed up by a rolled steel edge but it isn't big enough to locate two. Nev

now I know why I've always checked the metal face that the neoprene washer on the new oil filter bears against; I do this on any engine that I change the filter on. But I've never worked on a rotax.

 

 

[RickH]

As often as not it's used to confirm the appropriateness of, or extend further the oil drain periods of long haul vehicles. ED oils have additives which counteract certain chemical contaminants and the additives can wear out. All additives are something other than oil, but they do a job for certain specific applications.. Nev

This could not be further from the truth SOAP is not used to extend oil change intervals it is used monitor engine condition and provide early warning as to possible component failure. Never in my experience in maintaining aircraft have I seen or heard of any engine manufacturer recommending or advocating extension of oil change periods. If you can name one I would be very interested to have you provide a reference.

 

 

[Bruce Tuncks]

One thing I got from a book on engine maintenance was to use strong magnets around the oil filter. When you open the filter up, there sure is metallic sludge trapped by those magnets. Of course this would only be ferrous metal, but that is a lot of things in the engine.

 

I would use oil analysis if there was a body of knowledge about just what to look for in a Jabiru engine.

 

On the subject of oil change interval, Don Richter once said the 25 hour change engines were discernible at overhaul time.

 

If you do all this stuff right, then it should outweigh the Time Before Overhaul and you could overhaul on condition as Mike Busch says.

 

 

[Geoff13]

I like the concept of Oil samples. Even if there is no history or reference for your type of engine, a good sample will notify you of changes, and that can only be good.

 

 

[RickH]

One thing I got from a book on engine maintenance was to use strong magnets around the oil filter. When you open the filter up, there sure is metallic sludge trapped by those magnets. Of course this would only be ferrous metal, but that is a lot of things in the engine.I would use oil analysis if there was a body of knowledge about just what to look for in a Jabiru engine.

On the subject of oil change interval, Don Richter once said the 25 hour change engines were discernible at overhaul time.

 

If you do all this stuff right, then it should outweigh the Time Before Overhaul and you could overhaul on condition as Mike Busch says.

With regard to the sort of things to look for with Jab engines, having a look at the Jab engine manual there are bushes in the rocker arms whic at a guess would be some kind of bronze( copper tin etc.) Valve guides are likely to be similar. The main bearings are slipper bearings so most probably white metal (antimony ,tin ,lead zinc). then of course valve lifters and cam shaft these as I'm sure you are aware are the bits likely to wear. Jabaru should be able to tell you the chemical compositions of these components and this should give you a pretty good guide as to what to look for in your oil analysis.

 

 

[RickH]

https://gallery.mailchimp.com/dfd69bf8f8fec1b9da00eedbd/files/Critical_Component_Failures.pdf

 

I copied this link from another thread on this forum. If you are in any doubt about the benefits of oil analysis I strongly suggest you read this article.

 

 

[Bruce Tuncks]

Thanks Rick, good article

 

 

[diesel]

Last oil analysis on low time since oh on 0200 was interesting. Among the results was high silica. First thought was from bead blasting. Asked engineering, they thought dust up exhaust, breather etc as we had big wind for weeks. In short went back to putting an oily sponge up the exhaust pipe after shutdown. Chas

 

 

[facthunter]

Rick H, I did say ED (extended Drain) oils in long haul vehicles specifically. These oils are NOT used in aircraft but the oil analysis industry does get involved with what I covered in my first line. It's what keeps them in business to a great extent. Nev