Oil analysis

[tshort]

Any thoughts? This is the cut and paste from Blackstone (I don't know of a way to post the .pdf ? )

"Aluminum and chrome both improved slightly in this sample, though both still have a long
ways to go before we consider them normal. Copper and silicon increased. This is not a normal
occurrence for an engine this new and we are a bit concerned that a mechanical problem may be
developing. Silicon could be causing a lot of the wear if it's from abrasive dirt getting past the air filter.
This engine has been opened for work recently, then these findings may be normal. If it's running well
and the oil filter is free of any excess metal, check back in 20 hours."

Summary - this is about 34 hours on the oil, engine with 59 SMOH. Runs great, smooth, no problems, I cut the filter and found essentially nothing inside. I did have far longer than I normally do on the oil, but the engine was being run weekly.

Thomas

[GAHorn]

Analysis reports are highly speculative on such a new overhaul at best. Analysis is really only useful after an engine has established it'self with a half-dozen stabilized reports, which usually don't stabilize until after 3 or 4 oil changes anyway.
The high silicon may be (and probably is) an airbox leak. In a C145/O-300 this is very common that the carb-heat butterfly does not completely close in the cold position. This allows unfiltered air to enter not only from the muffler/scoop system, but also from the lower air box exit.
With a fresh overhaul such as this, unless actual metal shows up in the screen/filter, I'd recommend you disregard analysis reports. (If it were mine, I wouldn't even bother with analysis until 100 hours were on the engine...what would it tell you that you don't already know? ...that metals were reading high?)

[tshort]

That was kind of my thought. Stu (old timer A/P buddy who is my CFI also) is basically making fun of me for doing them. The filter had nothing in it when I cut it.

I'll have to check the carb heat butterfly before I recowl - thanks for the tip!

Thomas

[doug8082a]

Oil analysis is kinda like driving with a radar detector. You are always wondering about each little blip unless you know a particular road like the back of your hand and know where all the “false positives” (security systems, etc) are located. Once you know that, you don’t really need to worry until you get a blip in a spot where you never had one before.

I’m not saying oil analysis isn’t valuable, only that it is more meaningful over an extended period of time.

I threw my radar detector out years ago. Driving in Massachusetts is stressful enough.

[GAHorn]

Not only that, but to have a valid oil analysis program, it must be a sample taken at very nearly the same number of operating hours, and further, within the same drain sequence (preferably in the middle of the drain), and using the same brand/grade of oil, and tested by the same laboratory using the same methods (usually spectroanalysis, but not all labs use the same process, or calibrate their machines the same, etc.. ...that's why it's so important to use the same labs.)
False positives also exist. Some labs will report silicon (which is dirt, usually an intake/air filter leak) and some labs report silicone (which is synthetic rubber)... as if that were the same stuff when it actually resulted from an owner's replacing his rocker cover gaskets with silicone gaskets. This is because many labs actually do not employ "scientists" but employ low-wage, trained operators of the equipment who are merely putting in their time at the workplace and spend more time thinking about the ball game.
Analysis was hot/high-tech back in the early days of turbine engines and corporations/owners were scared of high engine prices. But most turbine engine mfr's finally offered some sort of engine-warranty/scheduled overhaul payment system (i.e. Power by the Hour (Rolls-Royce), or MSP (joking referred to as "Money Sent to Phoenix", home of AirReasearch/Honeywell Engine Div.). When some new engine designs warranty programs required it, SOAP (Spetrographic Oil Analysis Program) was introduced.
In any event, since it was good for the high-dollar/high-tech boys, it has been actively promoted/sold to the recip-market as a "must have."
I don't buy it. I change my oil every 25 hrs and check my filter and that's good enough for my tastes.
Some folks have had high pewter/aluminum reports and tore down their engines and found scored/galled pistons or seized piston-pins and swear by analysis. Unfortunately, analysis is usually best at catching damage that has already occurred, so it's rare that an actual/outright engine failure is actually prevented. (I don't know of a single documented case, although there are several anecdotal stories where it was presumed to have occured.)
If you inspect your engine carefully (most of us don't) and look for discolored cylinder paint and high cylinder temps accompanied by burnt oil and high oil temps, increased consumption (most of us don't even log added oil quantities, but we should) etc etc, I personally believe you'll catch what serious problems analysis will catch.

[CraigH]

But George,
You'll have to admit, the analysis just might have caught an airbox leak, which could potentially lead to increased engine wear. To me, that alone would justify the cost of the analysis. Oil analysis caught a similar leak in my Citabria.

[tshort]

I do all of the above - oil change at 25 hours, sample at the same point (clean catch mid stream, just like a urine sample), send it to the same lab, and use the same oil.
I also wash the engine down with every oil change and inspect / tighten everything, cut the filter, and keep a log of oil added. To me, the extra 20$ per oil change of an analysis is cheap insurance for what may or may not be useful information. The key, I think, is not getting scared / panicked based on a single oil analysis report.

T.

[GAHorn]

But George,
You'll have to admit, the analysis just might have caught an airbox leak, which could potentially lead to increased engine wear. To me, that alone would justify the cost of the analysis. Oil analysis caught a similar leak in my Citabria.

Yes, I admit it. So will a proper daily inspection, as called for in the TCM Manual, Form X30013, page 17, para. 1, "Daily Inspection, Item 4. Be absolutely certain that no air leaks exist in induction system at any point that would allow unfiltered air into the engine." Cost: Free.

I'm not trying to discourage anyone who wishes to avail themselves of oil analysis. I'm only stating my own feelings about it with regard to my personal airplane.

[CraigH]

Daily inspection. Hmmmmm. Sounds all well and good, but I'll bet most of the members (myself included) neglect to de-cowl their bird once a day to check the air induction system.

[GAHorn]

It's not as difficult as it first seems. Generally the entire system should be looked at during an oil change, and the engine washed down/inspected.
During oil changes/air filter serviceing, the airbox, carb heat butterfly, hose/clamps checked/tightened, etc..
During preflight it's easy to look up the lower cowl to see the condition of the airbox and hoses and clamps, carb mounting, etc. If a preflight looks at the air filter security, carb mount security, and hose/mountings, then that'a a good overall check of the security of the induction system. There aren't many places that air leaks occur that aren't pretty easily detectible if a regular look/see is made.
It's just a matter of recognizing the need and then applying the eyeballs during preflight.