For Anyone Using Aeroshell Multigrade

Recent oil analysis of my O320 (now at 600+ hours) showed a spike in copper. Where's it coming from? OK, I know the main bearing are copper, but they're clad, and I'd be seeing babbit material before copper. Pushrod guides are typically bronze, so there's a possibility there.
A call to Lycoming tech support lead me to find that in the heat treatment of their camshafts, the parts are first coated with a copper "flash". This is subsequently stripped off the lobes and bearing journals before the parts are sent into a carburizing furnace. The copper prevents the carbon rich atmosphere from selectively penetrating the surface - the result is higher carbon on the uncoated surfaces for greater wear resistance and normal base material on the coated surfaces for greater ductility.
After heat treatment, the copper remaining on the non-wear surfaces is still there but plays no role in any way in normal engine operation. Here's the rub- the multigrade shell has an agent that tends to strip off the copper and hold it in solution. No problem either way, but it will show up in oil analysis.
Terry, CFI
RV-9A N323TP

Good info

Long ago I spent a year certifying heat treating processes and facilities in Building 27 at MAC in St Louis for the McDonnell Douglas Corporation when the company was concurrently producing the F-4, F-15, AV-8B and subassemblies for the DC-9 and DC-10 so I know that heat treating can be a very specialized, tightly controlled an closely held secret activity. Getting the information as you have and providing it here is a valuable service. I do use Shell multigrade for the anti-wear properties and I run the engine at 2720 rpm (max I can get with my controller) for racing & testing and 2450 rpm for cruise/travel. After 600+ hours the compression checks and performance are good. I was afraid your post was going to give me some bad news.

Bob Axsom

i was afraid of bad news too. wheew

This thread has my name written all over it! My Lycoming O-360-A1A was new when first flown, and it was flown for 2500 hrs using Aeroshell 100W. Copper was 8 parts-per-million (ppm) for the life of the engine, and it was the increasing copper content that helped me decide to overhaul the engine at 2500 hrs.

New ECI cylinders were installed on the engine at overhaul. My hangar-mate had been using Aeroshell 15W/50 so that's what I put in after engine break-in (since I was out of Aeroshell 100W).

My first (and subsequent) oil analysis with Aviation Oil Analysis (AOA) at 50hr intervals showed my copper content in ppm as:
50hr: 64.9
100hr: 65.2
150hr: 66.8
200hr: 67.0
250hr: 47.9
300hr: 38.9
350hr: 40.7

From the history of the first engine stable at ~8ppm, I always thought these values high but AOA showed 'All values appear normal'.

While cleaning out the hangar, I found an oil analysis kit from Blackstone Laboratories: I think it was given to me free at Oshkosh. Since I already had several AOA kits on the shelf, I thought I'd send a sample at 400hr to both companies. The readings were consistent at 400hrs:

AOA: 40.9
Blackstone: 41.0

However, Blackstone's report included the following personalized statement:

"Paul, Your ECI cylinders are the reason nickel is reading higher than average, and you can expect it to stay perched at the 5-10ppm level as long as these cylinders are on board. It's fine as long as it's steady. Copper probably has a reasonable explanation as well: Aeroshell 15W/50 causes a chemical reaction with a coating on Lycoming parts. It's not a problem, really, though it does obscure your true reading. Any other oil, including Aeroshell oils, will bring down copper"

Spank me with a wet noodle but I didn't read the memo where ECI recommends Phillips 20W/50 X/C. I immediately drained the 15W/50 and put in the Phillips. On the next and subsequent oil samples, I saw continuous drops in copper. My 'new' normal is <10ppm Here's the latest report where you have to read the values from right to left:



I would recommend you try a different oil Rosie

No Need to Change

Paul:
As I noted, the copper showing up on the report as a result of the aeroshell is merely the result of the copper flash being slowly stripped off. This flash served its purpose during heat treatment and plays no subsequent role. The importance of these reports is in looking at trends. Nothing wrong with the Aeroshell. It does get your attention, though.
Terry

On more than one occasion I have seen/worked on/overhauled engines that have had major problems despite good oil analysis. For that reason I simply believe oil analysis is a waste of time and effort and often leads people to the wrong conclusions. Keeping an eye on your screen and filter will tell you 99.9% of what you need to know about wear in your engine.

Same here.

Oil screen debris/particulate comparison

rocketbob said:

On more than one occasion I have seen/worked on/overhauled engines that have had major problems despite good oil analysis. For that reason I simply believe oil analysis is a waste of time and effort and often leads people to the wrong conclusions. Keeping an eye on your screen and filter will tell you 99.9% of what you need to know about wear in your engine.

Click to expand...

I agree with Rocketbob on oil analysis intervals, however I still do an oil analysis every 3rd oil service just for record. One thing I do when I clean the screen, is I wash all particulate, if any, into clean white paper towel and then use clear packing tape and encapsulated it, then tag it with oil service time. It makes a very good easy visual reference at a later date if in doubt on screen debris/particulate comparison.

i like the ........

use of all three. screen for chunks( dont like this stuff), filter for the small stuff( carbon, small flakes), and the OA for parts / million( this is the fun stuff). i use spectrum labs in new jersey. i rotate between oil filter cut and screen check, and OA total 60 hrs.

My O-320 has had copper go up to 20ppm since 200 hours, running Aeroshell 15W50. The AOA lab even has a pre-printed comment code to go along with it: "Copper Appears Slightly High, Copper High Possible Due To Additive System In Shell 15/50"

Hihg Copper (Cu)

Thanks for posting the information above. It makes me feel a bit better. The Cu went up when I changed from Shell W100 to 15/50 as you can see in the analysis below. I change the oil every 50 hrs. I will change to the Phillips or the Shell W100 the next time:


Copper (Cu)ppm
10-Jun-12 16.94SAE 15W50
16-Apr-11 16.62SAE 15W50
10-Aug-10 16.80SAE 15W50
19-Jan-10 6.90AeroShell 100
19-Oct-07 3.80AeroShell 100
10-Jan-07 6.90AeroShell 100

I run Aeroshell 15W50 in my 172 with IO360, Cu is variable between 7 and 16ppm (average 12ppm) over the last 7 samples, 50 hrs each.