Spike on copper and silicon on oil analysis

P

peter-h

Line Up and Wait
Joined
Sep 24, 2007
Messages
613
Location
UK
Display Name
Display name:
peter-h
After ~ 10 years of doing oil analysis and the results being uneventful (except after a rebuild following the SB569 crank swap, when the numbers were elevated for a while) I have just got the data back from a 35hr old sample (IO-540-C4D5D) and get 2x the average (for the engine type, and also my history) on copper, and 2.5x on silicon.

The sampling company comments

NOTE INCREASE IN COPPER. COPPER CAN TYPICALLY BE FROM BUSHINGS, BEARINGS, OIL COOLER OR ANY BRASS OR
BRONZE PART. NOTE INCREASE IN SILICON. SILICON IS DIRT CONTAMINATION. THIS MAY BE CAUSED BY A DIRTY AIR FILTER, VACUUM
LEAK, FLYING CONDITIONS, THE SAMPLING PROCESS, ETC. PLEASE CONTACT THE ENGINE MANUFACTURER'S SERVICE REP FOR
FURTHER ASSISTANCE. WE WILL CONTINUE TO MONITOR WEAR METAL TREND ON YOUR NEXT SAMPLE

I wonder what I should do? Do another sample after say just 10 or 20 hours?

In the past I got a spike on copper by using copper-loaded spark plug thread lube, but I don't use it anymore. OTOH this is the first post-Annual sample and while I do the 50hr checks, I didn't do the Annual so maybe something go into the engine?

The silicon might be an air leak perhaps? The air filter was definitely changed.

Could the air leak cause the extra copper to come off the tappets etc? However, all other metals are normal.

The engine runs fine, to spec, compressions very good. EDM700 data consistent.
 
Last edited:
I would start by taking the cowling off and doing a visual inspection. Look at the air box alt. air door carefully and the work back on the induction system. I have a friend that found a defective alt. air door seal in his 206 after a high silicon reading. Catching it could easy have saved his motor from not making TBO.

If I couldn't find anything wrong I might fly it for another 20-25 hours and do another sample. I would be there when it was taken to make sure it was done right. If still high I would have the motor scoped, inspected, etc. and find the problem before I flew it more.

Just my opinion and I'm no A&P, but I am a believer in oil samples.
 
Tappets are steel IIRC. If a TCM I'd say check out the starter drive but that isn't your problem here. Odds are good the copper comes from one of the bronze bushings. I also would not be inclined to panic just yet either.
 
Do you mean bronze bushings in the conrods?

The top ones can be checked by removing the cylinders. The bottom ones?
 
peter-h said:
Do you mean bronze bushings in the conrods?

The top ones can be checked by removing the cylinders. The bottom ones?
Click to expand...

Bottom should be standard bearings. There are also engines that use bronze wrist pin caps as well as the valve guides
 
The input I have so far from "the business" is that this is not exactly abnormal, but that a check at 25hrs is a good idea.

I will also get the air filter replaced and the alternate air mechanism checked next week, as that pointer is fairly specific. I wonder if somebody has chucked some dirt into the engine? ;)

A spike in chromium etc would be a lot more serious.

This engine is 25% into its 2k hr TBO.

I fly about 100 airborne hours a year, at 65% power at low altitudes, and whatever power (usually well below 65%) at higher altitudes, up to FL200.
 
One other thing, Lycoming has been very helpful when I have called them. If I got another bad sample I might give them a call and see what they have to say.
 
Would you have a contact email ?

I used to have one but it went dead.
 
peter-h said:
Would you have a contact email ?

I used to have one but it went dead.
Click to expand...

I call them 570-323-6181 in the U.S. eastern time 8-5.

I don't see a published support email either... Strange.

As I said above the support people I've talked with have been very helpful and GA pilots themselves.
 
Skylane81E said:
Bottom should be standard bearings. There are also engines that use bronze wrist pin caps as well as the valve guides
Click to expand...

And rocker bushings. Lycoming had some difficulty some years ago with those.

Copper is often used between the steel rod and main bearing shells and the lead/tin alloy that lines the bearings. When bearings are being badly torn up copper can show up in the analysis, but the lead and tin should be off the charts, too.

Dan
 
:idea:IMO..... The Silicon is your biggest event to figure out... Elevated Silicon levels will come from a mis aligned airfilter, no airfilter, sitting is a VERY dusty and dirty location, scat tube leaking from the air filter box to the induction and I have even seen a MX use a dirty funnel during an oil change and all the sand, dirt, crap are washed into the engine as they pour oil into the funnel...

The elevated Copper numbers might be a result of that Silicon sawing the motor apart....

I would drain the oil, change the filter, maybe even pour in a little mineral spirits to flush the case, add new oil and recheck after 20 -25 hours. If the numbers stabilize then you have dodged a bullet.. If the Copper and other numbers are still up then you might need a closer inspection...

Ps... it is possible someone put some sand in your engine so loook VERY close at the dipstick tube to see if there is any sand / dirt in it... Unless they were very careful remnants of that sand/dirt will be embedded in the threads where the dipstick screws in.. :idea:
 
What is DC4?

Sand in the oil should not be very likely because I am very conscious of possibilities like that (vandalism) and the aircraft is not left out overnight except on very rare occassions. Unless done by somebody working in the hangar...

I have not been to any known-dirty locations.
 
Have you talked to Barrett ?
 
Did you recently switch to Aeroshell 20-50? Change your oil and air filter and see what happens.
 
Did you recently switch to Aeroshell 20-50? Change your oil and air filter and see what happens.
Click to expand...

I changed 2-3 years ago, so not recently.

15W-50, IIRC.
 
A very very loooong "all reps are busy" wait on that Lyco number.

Would anybody have a fax number for their tech support?
 
peter-h said:
I changed 2-3 years ago, so not recently.

15W-50, IIRC.
Click to expand...

You would be correct on the number and the likelihood of that revealing copper now would be unlikely without some other agent. So back to sabotage, what is in your filter? Can this be reasonably cleared in a couple of flushes?
 
We had a damaged air filter a couple years ago and the increase in silicon showed up at the same time the filter was found and replaced.
 
The report is here

I note that while the silicon has only spiked in the last sample, the copper was working its way up in the previous one, which tends to rule out the silicon as the cause of the copper spike.
 
Copper's been steadily climbing. I think that's the one that would concern me.
 
peter-h said:
The report is here

I note that while the silicon has only spiked in the last sample, the copper was working its way up in the previous one, which tends to rule out the silicon as the cause of the copper spike.
Click to expand...

Tin looks good.... Iron looks good.... Aluminum looks good..... Lead looks normal...... If the bearings and / or the crank /lifters /cam were going bad those number would show high.... I still think the air filter is getting by passed somehow that leads to the elevated silicon content... And the elevated copper should be investigated... maybe rocker arm bushings or pin bushings :dunno: Someone mentioned prop, I am not sure if there are any copper components it the prop assembly,,, maybe the governor :dunno:
 
Last edited:
No copper in the prop, but maybe in the governor.

Can the pin bushings be checked from the outside? The rocker arms are in the cylinder heads so should be very accessible.
 
Last edited:
Bout the only easy way to check the pin bushings would be to rock the prop back and forth while watching the piston through a plug hole.

FAR from ideal but it might work
 
Skylane81E said:
Bout the only easy way to check the pin bushings would be to rock the prop back and forth while watching the piston through a plug hole.

FAR from ideal but it might work
Click to expand...

The looseness you will feel is the gap in the ring to groove, allowing the piston to move before it moves the rings.

the .0001" looseness in the piston pin to piston and rod will never be felt by moving the prop. Neither will a rod bearing.
 
Tom-D said:
The looseness you will feel is the gap in the ring to groove, allowing the piston to move before it moves the rings.

the .0001" looseness in the piston pin to piston and rod will never be felt by moving the prop. Neither will a rod bearing.
Click to expand...

Boot looking for it in the prop. In theory you could see if the wrist pin bushing was gone because the piston wouldnt move immediately.

Odds of that test telling you anything, nearly exactly nil. But I can't think of any other way short of yanking jugs.
 
Could this kind of thing result in a catastrophic engine failure?

The oil filter has always been opened and has no metal at all, and I make sure this inspection is done and done 100% (mostly by myself). Too many firms over here skip it.
 
Skylane81E said:
Boot looking for it in the prop. In theory you could see if the wrist pin bushing was gone because the piston wouldnt move immediately.

Odds of that test telling you anything, nearly exactly nil. But I can't think of any other way short of yanking jugs.
Click to expand...
Can you see a .0001"

I can't.

the wrist pin fit is very close, even if it were worn beyond use it would only be .002"

if it is beyond that it will knock like crazy, and we would be in panic mode.
 
peter-h said:
Could this kind of thing result in a catastrophic engine failure?
Isn't this why we run trends on the engine?

The oil filter has always been opened and has no metal at all, and I make sure this inspection is done and done 100% (mostly by myself). Too many firms over here skip it.
Click to expand...

I'd be watching the oil pressure very closely
 
Tom-D said:
Can you see a .0001"

I can't.

the wrist pin fit is very close, even if it were worn beyond use it would only be .002"

if it is beyond that it will knock like crazy, and we would be in panic mode.
Click to expand...

Kinda what I was driving at:D
 
peter-h said:
Could this kind of thing result in a catastrophic engine failure?

The oil filter has always been opened and has no metal at all, and I make sure this inspection is done and done 100% (mostly by myself). Too many firms over here skip it.
Click to expand...

The answer is "It's too early to answer." We need more trend.
 
Wonder what the coating is on the cam shafts?
 

Attachments

  • Timing gears.jpg
    Timing gears.jpg
    72.7 KB · Views: 19
Alex - a very good point in that no bearings are made of pure copper. It is copper+zinc (brass) although the firm I use (Avlab) doesn't sample zinc. Others (most perhaps) are copper+tin (bronze) and tin is fine.

I believe most "serious" bearings/bushes are made from some form of phosphor-bronze.

Tom - I did wonder about leaching, though this engine was rebuilt in 2008, which is a fair time ago.

But overall it does look positive.

What is special about the oil cooler? Internal disintegration?

Looking at the actual copper numbers, the amount of copper in question is of the order of 0.05cc.
 
Last edited:
A little update:

There was a ~5mm gap in the alternate air intake door.

So plenty of air would have gone past the air filter.

Hopefully that explains the spike in silicon.

I am ~4hrs into the current oil and will probably change it at 15-20hrs and see if the copper is still there.

I cannot understand how one can get a spike in copper and not in tin. Are there really brass (copper+zinc) bearings in an engine? That would be a poor engineering material.
 
peter-h said:
A little update:

There was a ~5mm gap in the alternate air intake door.

So plenty of air would have gone past the air filter.

Hopefully that explains the spike in silicon.

I am ~4hrs into the current oil and will probably change it at 15-20hrs and see if the copper is still there.

I cannot understand how one can get a spike in copper and not in tin. Are there really brass (copper+zinc) bearings in an engine? That would be a poor engineering material.
Click to expand...
Bearings are either going to be Babbit which comes in a variety of alloys, some with and some without tin, or Clevite which will typically not have tin.
 
You must log in or register to reply here.
Back
Top