Oil analysis ... elevated Copper ?

mistergerf · #1 10-26-2007, 11:29 PM

I got my 5th oil analysis results back today (circa 200 Hobbs hrs) and they flagged the copper content as potentially an indicator of trouble. 44 ppm on oil that's about 50 hours in the engine, Aeroshell 15W50. They claim 7 ppm is the average.

Its been 44 ppm every 40 hours since day one, no trend up or down, but now they're saying it should have trended downward by now, after wear-in.

Anyone have any numbers to compare ?

g

Russ McCutcheon · #2 10-26-2007, 11:42 PM

I?ve only done mine twice once at 187 hours gave 16.3ppm and at 314 hours it was 6.6ppm for copper. By this yours sounds like it might be high, I have no advice for you, just the numbers for your comparison.

az_gila · #3 10-27-2007, 12:21 AM

Blackstone has a report explanation here....

http://www.blackstone-labs.com/aircr...port_expl.html

Copper is listed as...

Copper: Brass or bronze parts, bushings, bearings and oil coolers.

But if it's bushings or bearings...

Tin : Bearings, bronze parts (with copper), anti-wear coatings.

Zinc: Component of brass (with copper), oil additive common to auto engine oils.

So, if your tin and zinc readings are OK... have you checked out your oil cooler?

Perhaps a good flush and cleaning of the oil cooler might be in order....

....just a thought....

gil A

sprucemoose · #4 10-27-2007, 12:46 AM

Funny you mention. I just got my latest results back, and low and behold, elevated copper. I don't have the sheet in front of me, but it went from around 20-25ppm to somewhere in the high 40s.

I sample and send it in every 50 hours (about 9 times so far) so I have a good baseline. I'm not too worried about one sample, but I'll watch it. Perhaps there is a QC issue with the testing? (Just a thought.)

N184DA · #5 10-27-2007, 03:30 AM

Quote:

Originally Posted by mistergerf

I got my 5th oil analysis results back today (circa 200 Hobbs hrs) and they flagged the copper content as potentially an indicator of trouble. 44 ppm on oil that's about 50 hours in the engine, Aeroshell 15W50. They claim 7 ppm is the average.

Its been 44 ppm every 40 hours since day one, no trend up or down, but now they're saying it should have trended downward by now, after wear-in.

Anyone have any numbers to compare ?

g

I had a similar situation with my RV4, which has approximately 500 hours.
The last three oil analysis recorded abnormally high copper amounts, and all other particulates were within normal ranges. I use AeroShell 15W-50, and change the oil & filter every 25 hours.
After the third report, I called the company and asked for advice,,,

The technician told me that the high copper amounts could be related to the use of Aeroshell 15w-50, which is the oil I have used since break-in six years ago.

Apparently,,, and I do not know all of the details,,, Shell changed the formulation of the oil sometime last year and the explanation the technician gave me was that the oil may be the cause, and the copper is not due to abnormal wear.
After a few Google searches on the web, I found numerous reports essentially echoing the tech's report.
From what I was told, after the spike in the copper analysis, Shell once re-formulated back to the original but there is still quite a lot of the "second-formulation" oil left in stock.

The tech further advised me that in order to validate the source of the copper, I would have to purchase new oil, from a recent lot number,,, or switch to something like 100w temporarily,,, run the engine for the 25 hours and have the oil analyzed.

I am no chemist, so I cannot explain what is happening on a molecular level, but the existence of so many similar reports from users of AeroShell 15W-50, gives me some degree of comfort. As soon as I run the time on the current oil, I will replace it with a "test batch" of something different, and compare the results.

plehrke · #6 10-27-2007, 05:29 AM

I have seen the same high copper readings using Aeroshell 15W50. I have done 5 oil analysis so far in the 170 hours I have in the last year on my RV-6A. I use Staveley Services (AOA) for my analysis. They actually have a code 994 that states it may be high due to use of 15W50. Mine reading started at 28 ppm on the first use in April this year and has slowely dropped by 2-3 ppm per oil change. Now down to 18. I happen to have a friend that camped next to the vic-president of Blackstone Oil service at Oshkosh so I asked him the question. He stated that it was OK and should slowly come down as the engine broke in more. He did not mention that is was a change in the oil formulation and that Shell was changing back.

RV6_flyer · #7 10-27-2007, 05:54 AM

Is everyone using the same lab?

I remember a number of years ago that Shell reformulated the additive that is in AeroShell 15-50 and the additive would show up in oil analysis as high copper.

I do not have time to look up the article. Check AvWEB and the Matronics RV-List search engine.

I have run Aeroshell 15-50 more than 90% of the time in my engine since I rebuilt it over 2,050 hobbs hours over the past 10-years. A thread similar to this one was around once before.

mahlon_r · #8 10-27-2007, 08:25 AM

As I recall, the additive was an anti scuffing agent and when it got mixed with water, from condensation inside the engine, it made nitric acid, which leached the copper off many of the copper flashed parts in the engine. As I recall, the additive was a ?tri? something originally and got changed to ?di? something of similar properties but was way less carcinogenic (or maybe the otherway around).
Sometimes, with very inactive engines, that left the oil and condensation water on the parts for a long time, due to the inactivity, not burning the water out, you would actually see super fine copper in the oil filter.
Almost all of the gears and the cam are copper flashed on the non hardened surfaces and that is where the copper came from.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

mistergerf · #9 10-27-2007, 10:47 AM

Blackstone did suggest switching to 100W so they could better analyze the copper, brass and bronze content. I doubt it has anything to do with condensation in an inactive engine - it flies at least every other day and my oil temps are rarely below 180.

Thanks all for your comments - I'll keep you posted on what develops.

g

RScott · #10 10-27-2007, 11:22 AM

I have access to a spectrometer & do oil analysis for friends & on my own engine, a Continental. Only one guy with a Lycoming has taken full advantage of my offer & he has flown 700 hrs on his Aerosport engine, sampling regularly. Most others have only given me one or two samples.

On his engine, the high was 33 ppm, coming after about 1 year of flying and I am guessing at about 125 hrs. It has since trended downward to 8-10 ppm in the last 2 readings. I believe he uses Aeroshell 15W50.

Here are his readings:

13.0 28.3 30.6 32.6 29.9 16.8 15.9 11.3 8.3 21.3 10.4

I have run 42 samples from various piston engines (& thousands of samples on jets). Readings of 33 on 2 piston engines were the highest of the 42 samples and most run 10-15 ppm.

Sometimes some metals are used as additives for some reason. We ran samples of unused oil & they had no copper in them.

Be sure to use the same lab all the time. Different spectrometers may give different readings and there are 2 basic different spectrometer concepts (atomic emission vs. atomic absorption), one of which gives readings approximately twice as high as the other. Trends are the important thing, not specific readings. Your lab was doing the right thing in telling you that your copper should be starting to trend downward.

Richard Scott
RV-9A Fuselage