Oil analysis

455 Bravo Uniform

Final Approach
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455 Bravo Uniform
Chrome came back high 80+ppm, average for IO-470 is 11ppm. All other metals in normal range. No prior reference samples.

As far as I can tell from my logs, I don't have chrome cylinders.

(1) What do you think it is?

(2) How can I tell from the outside if I have stock TCM, Millenium, or other cylinder?
 
Chrome can come out of the rings and can also be found in the cylinders if they’re steel. If chrome is a meaningful wear metal on your engine, the report sheet should say, although that does seem rather high.

As for (2): Do your cylinders not have the manufacturer on the head? All cylinders that I’ve seen have the branding stamped onto the cylinder head.
 
Thanks Ryan. They actually called me. I didn't ask if they normally call or if they called because it was an odd result. They pointed to the rings too, because I told them the cylinders were stock.

The engine is a TCM Gold Medal rebuilt that went through another overhaul a few years ago. Nothing I can find in the logs shows the cylinders were replaced, so I assume they are stock TCM. I want to actually confirm by eyeball that they are indeed factory cylinders.

Compression check and borescope next.
 
Hmm. Yours sounds a little more worrisome than our long-term elevated aluminum.

Let us know what you find.
 
The base of the chrome cylinders in my engine are painted orange. I also know that some just paint some of the fins orange.
 
Thanks Ryan. They actually called me. I didn't ask if they normally call or if they called because it was an odd result. They pointed to the rings too, because I told them the cylinders were stock.

The engine is a TCM Gold Medal rebuilt that went through another overhaul a few years ago. Nothing I can find in the logs shows the cylinders were replaced, so I assume they are stock TCM. I want to actually confirm by eyeball that they are indeed factory cylinders.

Compression check and borescope next.
Another quality overhaul with the same old cylinders, just have to wonder what other old parts that would have been replaced with a factory overhaul are still in use.
 
Another quality overhaul with the same old cylinders, just have to wonder what other old parts that would have been replaced with a factory overhaul are still in use.

This was a "Gold Medallion" TCM factory rebuilt engine (has since been overhauled) that I assume has some sort of factory cylinders. Whether the cylinders were new or refurbished, I don't know, nor do I assume that some prior owner didn't replace them at overhaul. That's why I want to be able to try to ID them externally to confirm.
 
The base of the chrome cylinders in my engine are painted orange. I also know that some just paint some of the fins orange.

Thanks. No orange on mine, but it's been overhauled once so the paint may be gone.
 
Useless





How's the oil filter cut look?
CHTs
Oil temp and Pressure
Oil burn
Performance

All operating parameters have been normal.

Three tiny flecks of a white non-ferrous metal in the filter. Like 1/64" to 1/32" in size. My mechanic did not like it. To me it looked like bearing metal, but bearing metals were low in the anslysis (If it was my race car, I'd run the snot out of it, but I just roll it onto the trailer if it craps out...not the same as being airborne with precious passengers). Chrome would be magnetic, right?
 
Chrome would be magnetic, right?
Chrome itself isn't magnetic most of the time. Warm it up a bit and it will be sorta magnetic.

Chrome plated material may be magnetic if the substrate is magnetic.
 
Over 7X the average amount of chrome present in the analysis would be a point of concern to me. Chrome cyclinders have a very unique appearance on the interior walls and can easily be checked with a boroscope. Also, chromed lifters, piston rings and push rod ends should be considered in your investigation as they are high-wear items. A differential compression test would be an easy way to compare cylinders but might also indicate abnormal valve or valve seat wear. If the next analysis shows 15X the allowable amount of chrome, what will you do?
 
All operating parameters have been normal.

Three tiny flecks of a white non-ferrous metal in the filter. Like 1/64" to 1/32" in size. My mechanic did not like it. To me it looked like bearing metal, but bearing metals were low in the anslysis (If it was my race car, I'd run the snot out of it, but I just roll it onto the trailer if it craps out...not the same as being airborne with precious passengers). Chrome would be magnetic, right?


Ahh.

I'd run it carefully (like not night or IMC or mountains) to the next oil change and cut it one more time.

If you find metal again.....


But I don't have a good feeling about this
 
Another quality overhaul with the same old cylinders, just have to wonder what other old parts that would have been replaced with a factory overhaul are still in use.
Speculate much? That’s quite the claim without any evidence. New cylinders are certainly not immune.
 
Over 7X the average amount of chrome present in the analysis would be a point of concern to me. Chrome cyclinders have a very unique appearance on the interior walls and can easily be checked with a boroscope. Also, chromed lifters, piston rings and push rod ends should be considered in your investigation as they are high-wear items. A differential compression test would be an easy way to compare cylinders but might also indicate abnormal valve or valve seat wear. If the next analysis shows 15X the allowable amount of chrome, what will you do?

Just thinking one step ahead at this time: scope and compression test. If nothing jumps out, another filter check and oil test at 10-15 hrs...or do a precautionary tear-down (now or at 10-15 hrs). One step at a time, let's see what happens next.
 
Late night Internet research. Last sentence of the Chrome paragraph. This engine came from the factory in the early 1990s. What if - the same damn exhaust valve guides are still in the heads?

Back in the 1980's when we had automotive heads being rebuilt for street-strip or strip duty, we would have the valve guides knurled for tighter clearance and oil control on worn out guides (was cheaper and we never needed them to last thousands of miles). In the aviation world, did people do the same knurling with valve guides? If so, do they still?

If these heads are factory TCM from 1990 a (need to check the logs) and the valve guides looked "good" during the 2000s rebuild (because of their hardness), maybe they were left as is and they are chewing up the sides of the valve stem. Anyway, something else to check.


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