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What's putting copper in my engine oil?

moespeeds

moespeeds

Well Known Member
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I get an oil analysis done pretty much every oil change. Back in Sep 2023 I changed all 4 cylinders due to one being cracked and all 4 being part of the Titan/ECI AD.

Since then, I've been making copper. Nothing significant in the filter or screens, borescope looks fine.

Seems like my silicon, copper, and iron are always elevated. I fly the plane pretty regularly, about 2-5 hrs a week. It is in a insulated hangar.

Any thoughts?
 

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moespeeds said:
I get an oil analysis done pretty much every oil change. Back in Sep 2023 I changed all 4 cylinders due to one being cracked and all 4 being part of the Titan/ECI AD.

Since then, I've been making copper. Nothing significant in the filter or screens, borescope looks fine.

Seems like my silicon, copper, and iron are always elevated. I fly the plane pretty regularly, about 2-5 hrs a week. It is in a insulated hangar.

Any thoughts?
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One thought is the anti-seize being used on your spark plugs if it is copper based.
 
Iron is that corrosion that they spoke to in your report. Chromium from the rings. Aluminum possible from wrist pin or piston. Copper from the bronze in your bushings. Possibly the wrist pin connecting rod bushing.

You could call up blackstone and ask them too. They would be able to help you.
 
My engine was manufactured before the rod end bearing AD, 2005.

The copper suddenly rose after the cylinder change, but it 15 ppm a significant rise?

I do use copper antiseize, and if i remember correctly, the new wrist pin caps were bronze instead of the aluminum I'm used to seeing.
 
moespeeds said:
My engine was manufactured before the rod end bearing AD, 2005.

The copper suddenly rose after the cylinder change, but it 15 ppm a significant rise?

I do use copper antiseize, and if i remember correctly, the new wrist pin caps were bronze instead of the aluminum I'm used to seeing.
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Was the piston changed, or the rod end bearings changed with the cylinder?
 
moespeeds said:
Yes, first 10 hours. Ran engine hard as well.
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The high amount of silicon generally implies dust or additives in the oil. The only high silicon steel alloy I'm aware of is 92-- series which is typically used for springs, not components that might wear. I have no clue about the copper. The low amount of tin in the oil points to the bronze being just fine.
 
moespeeds said:
I get an oil analysis done pretty much every oil change. Back in Sep 2023 I changed all 4 cylinders due to one being cracked and all 4 being part of the Titan/ECI AD.

Since then, I've been making copper. Nothing significant in the filter or screens, borescope looks fine.

Seems like my silicon, copper, and iron are always elevated. I fly the plane pretty regularly, about 2-5 hrs a week. It is in a insulated hangar.

Any thoughts?
Click to expand...
I replaced my cork valve cover gaskets with silicon gaskets which resulted in a big spike in silicon on my oil analysis reports.
 
drill_and_buck said:
I replaced my cork valve cover gaskets with silicon gaskets which resulted in a big spike in silicon on my oil analysis reports.
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Probably not the root cause -- Silicon ( Si - element #14) isn't the same as SiliconE.

The spike is probably due to a dirty airfilter and/or increased dust in the air -- which is common in the summer months in the southern US due to saharan dust in the atmosphere; Beautiful sunsets and spikes in oil analysis...
 
from memory but I believe the torque plates are required when removing cylinders. I have no details but a friends 10-1 0 320 was destroying the center main bearing, likely because the proper cylinder installation procedure was not followed. The center main dowels are also highly recommended to avoid this. I had the dowels done in the 70's on a stock 0 360 so this is nothing new.
 
My silicon was from the leaky alternate air door.
Blackstone didn't even comment on the copper --- so seems like it wasn't a big concern on their part.
 
bjdecker said:
Probably not the root cause -- Silicon ( Si - element #14) isn't the same as SiliconE.

The spike is probably due to a dirty airfilter and/or increased dust in the air -- which is common in the summer months in the southern US due to saharan dust in the atmosphere; Beautiful sunsets and spikes in oil analysis...
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This is the note I got back on my Blackstone lab report....
"MIKE: Thanks for letting us know about the silicone valve covers installed prior to the last oil change. That explains the jump in silicon last time and you can see that stuff is washing out of the engine since silicon dropped down to just 13 ppm. "
 
drill_and_buck said:
This is the note I got back on my Blackstone lab report....
"MIKE: Thanks for letting us know about the silicone valve covers installed prior to the last oil change. That explains the jump in silicon last time and you can see that stuff is washing out of the engine since silicon dropped down to just 13 ppm. "
Click to expand...

Thanks for sharing, but that's not accurate.

Prove it to yourself -- Take apart a valve cover and inspect one of the seals, closely. Has it degraded in any way? Does it flake or abrade? Is the luster of the material different between the surfaces exposed to engine oil and those that aren't?
 
bjdecker said:
Thanks for sharing, but that's not accurate.

Prove it to yourself -- Take apart a valve cover and inspect one of the seals, closely. Has it degraded in any way? Does it flake or abrade? Is the luster of the material different between the surfaces exposed to engine oil and those that aren't?
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Silicone is a compound that contains silicon. Given the small amount of silicon reported (13PPM) I think it would be very difficult to prove or disprove, by visual inspection, that the gaskets were the source of the silicon. Could have been some manufacturing residue on the new gaskets. Given that a new air filter was also installed when the valve cover gaskets were installed, and the sample was taken during winter operations, I'm more inclined to believe that the gaskets were the contributing factor. Cause and effect or coincidence? Your call.
 
Did you check the push rod clearances when you changed the cylinders? I think the rocker arms have Copper/Bronze bushings. Something easy to check.
 
drill_and_buck said:
Silicone is a compound that contains silicon. Given the small amount of silicon reported (13PPM) I think it would be very difficult to prove or disprove, by visual inspection, that the gaskets were the source of the silicon. Could have been some manufacturing residue on the new gaskets. Given that a new air filter was also installed when the valve cover gaskets were installed, and the sample was taken during winter operations, I'm more inclined to believe that the gaskets were the contributing factor. Cause and effect or coincidence? Your call.
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Dust is a compound that contains silicon -- almost 50% by mass. Siloxane (silicone ) contains ~28% Si.

So what's the more likely source of Si in the oil? The constant ingestion of silica (dust, dirt), combustion, and deposition into the oil through the combustion chamber OR the thimble-full of oil that touches the < 1mm * 482mm * 4 of exposed silicone gasket material inside the rocker arm/cylinder head?

Possible causes - some or all:

1. an air leak between the filter and cylinder heads
2. hole(s) in the filter media
3. particulate size smaller than what the filter can catch...

...and for what it's worth, I'm running with silicone gasket seals, and my Si report is very low -- 4.4ppm...

Personally, I'd be looking for air leaks in/around the air filter, or induction leaks -- have you noticed a wonky EGT reading? popping when you close the throttle?

P.S.
One additional thing that I forgot to mention, Siloxane won't break down until it exceeds +230°C (+450°F) for a number of hours. So, unless your cylinder heads in the gasket area are at this temperature or higher, the gasket material isn't the source of Si in your oil analysis.

This is why some cookware, oven mitts, cookie sheets, etc. are made from Siloxane.
 
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bjdecker said:
Dust is a compound that contains silicon -- almost 50% by mass. Siloxane (silicone ) contains ~28% Si.

So what's the more likely source of Si in the oil? The constant ingestion of silica (dust, dirt), combustion, and deposition into the oil through the combustion chamber OR the thimble-full of oil that touches the < 1mm * 482mm * 4 of exposed silicone gasket material inside the rocker arm/cylinder head?

Possible causes - some or all:

1. an air leak between the filter and cylinder heads
2. hole(s) in the filter media
3. particulate size smaller than what the filter can catch...

...and for what it's worth, I'm running with silicone gasket seals, and my Si report is very low -- 4.4ppm...

Personally, I'd be looking for air leaks in/around the air filter, or induction leaks -- have you noticed a wonky EGT reading? popping when you close the throttle?

P.S.
One additional thing that I forgot to mention, Siloxane won't break down until it exceeds +230°C (+450°F) for a number of hours. So, unless your cylinder heads in the gasket area are at this temperature or higher, the gasket material isn't the source of Si in your oil analysis.

This is why some cookware, oven mitts, cookie sheets, etc. are made from Siloxane.
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Thanks Brian, all good points to consider.
 
jrs14855 said:
from memory but I believe the torque plates are required when removing cylinders. I have no details but a friends 10-1 0 320 was destroying the center main bearing, likely because the proper cylinder installation procedure was not followed. The center main dowels are also highly recommended to avoid this. I had the dowels done in the 70's on a stock 0 360 so this is nothing new.
Click to expand...
Torque plates were used, and cylinders were installed properly. No tin in the sample, so not likely to be bearing material. Also nothing in the filter or screen, the only copper we're seeing is microscopic.
 
moespeeds said:
Torque plates were used, and cylinders were installed properly. No tin in the sample, so not likely to be bearing material. Also nothing in the filter or screen, the only copper we're seeing is microscopic.
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Bronze bushings would have a relatively high copper concentration and comparatively low tin concentration. Is it possible that the tin concentration is below the minimum test value?
 
If I had a dollar for every time someone got a concerning oil analysis that wasn’t anything, I could buy a new engine.
Not saying yours isn’t pointing to a potential problem , but…..
 
jrs14855 said:
Lycoming dropped the aluminum piston pin plugs years ago.
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Keep in mind that if only changing one cylinder on an older Lycoming engine that has the aluminum alloy piston pin plugs; you need to use the same plugs. The bronze alloy plugs are significantly heavier. I know because I weighed them. The complete Lycoming cylinder replacement kit came with the Bronze alloy piston pin plugs. My engine is a O-320 B3C wide deck 160 HP, constant speed Hartzell prop.
 
bjdecker said:
Crankshaft bearings are wearing. What's your idle RPM typically?
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Low idle is 650, but I typically idle at 900 and lean it to death. No evidence of copper or any significant particulates in the filter or screen. Both Blackstone and Savvy agree it's not bearing material without more TIN or particulates in the filter. They are pointing at the piston pin plugs and the valve guides.
 
moespeeds said:
Low idle is 650, but I typically idle at 900 and lean it to death. No evidence of copper or any significant particulates in the filter or screen. Both Blackstone and Savvy agree it's not bearing material without more TIN or particulates in the filter. They are pointing at the piston pin plugs and the valve guides.
Click to expand...
There’s been some anecdotal evidence of bearing wear caused by low idle speed and corresponding low oil pressure especially “up front” with tail draggers. The thinking is that the nose bearing isn’t getting the oil flow that it needs. FWIW.
 
bjdecker said:
There’s been some anecdotal evidence of bearing wear caused by low idle speed and corresponding low oil pressure especially “up front” with tail draggers. The thinking is that the nose bearing isn’t getting the oil flow that it needs. FWIW.
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Understood. My oil hot pressure at 900 RPM is 53 PSI. That doesn't explain the sudden and sharp increase, which also corresponded to the top overhaul.
 
Blackstone told me I had high silicone on several oil analyses, suspecting an intake leak. I was using a homebrew crankcase dehumidifier that incorporated silicone desiccant beads. I neglected to install a filter in the tubing coming out of the desiccant jug. After installing an in-line filter, the silicone in the oil disappeared.
 
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