Thinking of buying a 6V92, had oil analysis done, marginally elevated Fe?

[daveola]

Some of you may know that my transmission died, and my engine is getting pretty old.  I ran across a bus with a supposedly solid engine and transmission that I am thinking of buying to be a donor for my bus.

Stats are:  Detroit Diesel 6V92 + Alison HT740
The engine was supposedly rebuilt about 60k miles ago, though it's been around 10 years.  The rebuild was actually done by Detroit, which is a good sign.

The bus is far from me, so I took it to a mechanic to check it out.  There are no two-stroke diesel mechanics in the area, so I took it to a truck shop.  It starts up fine when it's cold and isn't really dripping any oil or blowing smoke.  That's a good sign.  Drives fine, too.  I had them pull the transmission oil and engine oil, and this is where I get slightly worried.


The lab results came back - the transmission oil is fine, but the engine oil had elevated metals, specifically 100ppm of Iron (Fe) and 19ppm of Tin, and the diagnosis says:  "Wear metal(s) high-indicating possible cylinder wear and piston scuffing."  Everything else reads normal, and it's marked as "Caution" as opposed to "Sever" or "Abnormal" or "Normal"

So..  how freaked out should I be about that?

The oil was supposedly changed maybe 10k miles ago, but who knows - the mileage on the bus isn't completely clear, and there's no way to be sure about these kinds of things...

Any thoughts on how much of a danger sign 100ppm of Iron is on an engine that seems fine otherwise and was supposedly rebuilt 60k miles ago?

[DoubleEagle]

Going by memory only, I believe above 10 for tin is the beginning warning level, and above 300 for iron, but that was for 4 cycle diesel. If those were the only two items out of bounds on the report, that is not too bad for an engine that has 10,000 miles on the oil and may have been sitting for a while. Any rust in the system would add to the count. If the oil pressure is good, and there was no long lasting smoking going on at startup, and no pronounced oil dripping, you are ahead of the curve. Price becomes a deciding factor. The main thing is absence of overheating signs or antifreeze in the oil. New main bearings could be spun in at not too great a cost, if need be.

[eagle19952]

pull the air filter and bounce it on the pavement...if it rains sand...well ..  it's probably been dusted..

[christopher]

call this guy
he will tell you what the deal is
http://www.infielddiesel.com/service.html

chris
mci5c

[luvrbus]

The warning limit on a 6v92 for iron is 150 PPM FeMax go for it, 100 ppm is not bad for 60,000 mile 6v92 that could be from the gear train normal wear if any gear was replace  Glycol is the killer,? what was the copper 

[Oonrahnjay]

... Glycol is the killer,? what was the copper 

     Yes, moderate levels of iron are a normal break-in component in oil.  Silica indicates a bad air filter or an induction air leak.  Glycol (antifreeze) in the oil is a BIG danger sign, it very likely means that the engine was overheated to the point that gaskets don't seal (i.e. damage to the block or heads); plus, oil with antifreeze in it will kill bearings and rings in just a few miles.  Copper and tin are from bearings -- you're going to have *some* copper and tin, esp. in an engine that has oil that was run past the oil change interval, but too much is deadly.

    You've already said this engine is showing moderate iron, that's probably not a terrible sign.  If the silence on glycol and silica means those numbers are good, that's very positive.  The tin is a little high but if the copper is normal, I wouldn't worry about it.

    Once you've very carefully looked at the full report and nothing more than what you've noted here is indicated, my guess is that you'd be good to change the oil, run it for 2000 miles and change it again, then do another analysis at the proper interval.  If you treat that engine right, you'll probably find that it's OK; about the worst you'd find is you'll have to replace bearings but that's reasonably easy and not a big $$$ shocker on an engine you got a good deal on in the first place.

     On the other hand, every used engine is somebody else's hand grenage ...

[daveola]

pull the air filter and bounce it on the pavement...if it rains sand...well ..  it's probably been dusted..

Dusted?

[daveola]

The warning limit on a 6v92 for iron is 150 PPM FeMax go for it, 100 ppm is not bad for 60,000 mile 6v92 that could be from the gear train normal wear if any gear was replace  Glycol is the killer,? what was the copper 

Copper was 26.

If the warning is 150 ppm, why was it noted as 'caution'?

Just different levels for different test companies?

[luvrbus]

The copper is over the warning limit of 25 ppm for 6v92, only bad thing about a oil sample you need 2 so you have a base to go by,I have no idea why they flagged the iron, 150 ppm is the same for a series 60 Detroit  

[eagle19952]

Dusted?

the air filter was deteriorated of past it's useful life.

it could have passed grit into the cylinder causing the scuff.

commonly referred to as dusted

[daveola]

The copper is over the warning limit of 25 ppm for 6v92, only bad thing about a oil sample you need 2 so you have a base to go by,I have no idea why they flagged the iron, 150 ppm is the same for a series 60 Detroit  

One companies warning is different from another, it would seem.  That's why it would be great to know what the ranges are.

What ranges of copper and iron ppm do people think are acceptable?

[HB of CJ]

Usually, (but not always) the normal range of various engine, transmission, radiator, rear end and hydraulic motor contaminants  will be listed on the results sheet.

Usually a computer printout but sometimes only hand written.  What might work would be to befriend a knowledgeable shop who trades with just a couple of good labs.

They might take a little time and explain it all.  Sometimes a gratuity helps.  Too many numbers to memorize.  These tests today are very comprehensive and very helpful.

Kinda like a human blood test workup.  All sorts of numbers we were at one time expected to memorize.  Mistakes happened.  Nowadays all printed out for us.  Yikes!

[daveola]

the normal range of various engine, transmission, radiator, rear end and hydraulic motor containments will be listed on the results sheet.

I know - I was surprised (and disappointed) to not see them.

[eagle19952]

i would have to question if the sample was even done...
how much did you pay?
who actually drew the sample?
was it a separate sample or part of a batch?
i have sold/serviced a lot of samples....
a single sample not on a scheduled contract was close to a $100.00
$70.00 was the least...

[luvrbus]

I would say over 1/2 of those people don't even know how to pull a sample ,I saw people do some crazy stuff trying to do a sample