I've recently done an oil change on my 88 350 TPI. I've sent a sample of the used oil to a company that checks all residues of metal or anything else in a laboratory. They told me that I have an amount of 149 mg/kg of copper in my oil... How can copper get into the engine oil? I've sent a sample of my 92 305 to them at the same time, there is an amount of 2 mg/kg copper in oil, absolutely perfect.
How is this possible? Any ideas? The engine is bone stock and has just 20k mls on the odo. Runs strong without any problems or noises.

 

The crank and cam bearings are made of copper.

This is not a good sign. Usually means one or more bearings are wearing very fast.

I don't see how it would be possible to have that much copper in the oil and at the same time, no other symptoms. That seems strange to me. One would expect to see low oil pressure, hear knocking, etc.

 

Many crank, rod, and cam bearings have copper content. Trimetal bearings have a copper underlay, aluminium/silicon overlay with a nickel barrier layer...... if you have gone into the copper then the bearing is pretty far gone as you are into the "soft" core of the bearing material.

You have the filter on hand still? I would cut it open to check for flake. I do this on many oil changes as a routine. You can generally spot something going wrong in a SBC without sending off lab samples. These aren't space rockets.

GD

 

That is what I am wondering about. Absolutely no knocking, oil pressure is perfect, never under 30 psi. Says the oil pressure gage... I will verify with a manual gage in a few days.

But why do I have perfect oil pressure and zero problems or noises? I still have the oil filter, good idea to look into it...

 

Yeah look into the filter.

Is this a new engine? Is this the first analysis?

Could be early stage failure where there's not much play yet in whatever bearing is getting loose. Stock SBC's are priority cam oiling so it's likely not a cam bearing if the pressure is good. Oil pressure may not really show a significant drop on a rod bearing worn down into the copper underlay - not at least till it gets loose and "spins", etc. It's so far down stream from the gallery feeding the sending unit, and is only 1 of 8. Critical thinking time - if one rod has twice it's normal clearance but isn't yet audibly knocking and *everything else* is still nominal..... would you be able to detect *less* than 1/18th drop in oil pressure? Now I'm sure that my math doesn't match up with the fluid pressure dynamics involved here, but just considering that one rod bearing is only one bearing out of 18 bearings (5 cam, 5 crank, and 8 rod) being fed by the same pump..... I don't believe an early stage failure that's not knocking would be seen on the factory "instrument trim package" as Sofa calls it.

GD

 

distributor bushing problem could also be a source of copper debris in oil.

 

I believe GD may be onto something. If this is analysis on a relatively "fresh" engine the initial numbers could be high. 149 PPM (mg/l or mg/kg for you who have never been to the moon and back) is a relatively low level for a new/not yet broken-in engine. Did they also report the nubers for zinc, tin, and molybdenum in the analysis?

 

Is 88 a roller cam year? IIRC roller cams use a brass dist gear, dont they? Somebody correct this if im wrong.

 

I don't think it's the distributor gear. GM used a Melonized steel distributor gear with factory hydraulic roller cams.

However, if the copper is coming from a copper alloy distributor gear, I think you'd expect to see elevated tin numbers (how much??) in the analysis too.

 

No, the engine is bone stock from 88, roller block, 350 TPI. I have disassembled the intake two years before because of a small oil leak on the rear china wall, while doing that I changed the valve seals because they were 30 years old... Everything is factory, except for a few sensors, plugs, wires and so on... It has original 20.098 mls on the odo today. Runs great, passes german emissions test every two years, doesn't smell, doesn't burn oil (new valve stem seals), gas mileage is fine. Oil pressure is NEVER under 30 psi. I know, the instrument is not as reliable as a manual gauge. From time to time I check the pressure on both cars with my manual gauge to verify that it "indicates" correct. You are right, I think I wouldn't be able to detect one worn rod bearing when the other bearings are good... I guess, I have found a way to get over this corona crisis or maybe it is an upcoming winter project. I need to buy oil for my garage heating unit for the winter...

They did, here is a screenshot of the other elements. It is obviously in german, maybe you need a translator.




The distributor is stock from factory. I had it out two years before and inspected it because I had a gear failure on my 92 engine without ever finding out what the culprit was. Bought a complete new distributor, never had problems again.

 

No translator needed, since the periodic table is fairly universal.

What kind of oil was being used? How long has it been in the sump?

 

Do the heads have valve guides?

 

I use Mobil Super 3000 X1 5W-40 with an extra bottle of ZDDPlus at every oil change. The oil was in the engine for exactly 666 mls (funny). I change the oil every year in march right before the season starts, no matter how much mls I have driven over the year. At the last oil change I was out of ZDDPlus, that's why the zinc isn't really high in the analysis.
You can't buy it here officially because of evil stuff for environment blabla, I have to import it from the US.

 

 

Any new engine will get a little stuff in as it wears in. If its real excessive then maybe pay closer attention.
Id drive it for now & keep an eye on it...unless you can see a lot of it when you change the oil

 

Did you send to Blackstone? I thought they would tell you if you were going to run into bearing trouble soon using their analysis. BTW - are they operating normally? I need to send in a sample for my other car.

 

Nope, I am in germany. I will cut up the oil filter tomorrow, my broken leg is a PITA for every little task.