ZVW30 Engine Oil Analysis

[bwilson4web]

Hi,

I'm not a great fan of engine oil analysis because I treat it as a consumable as it is changed so frequently. Worse, it carries a boatload of combustion products. To me engine oil analysis is like trying to figure out something by looking at the poop. Regardless, here is my 5,000 mile, first engine oil sample test results:

• I have no idea what oil was put in the engine in Japan
• I have no idea if this is good, bad or ugly ... it is one data point

FYI, I have no financial interest in R&G labs but find their testing service to be reasonable and complete (the 40C and 100C viscosity tests being key.) Use whatever lab you want but please share the results here.

I will test the second change but I'll do it and switch to Mobil 1 and send a reference sample to R&G so we can start a serious analysis. As far as I'm concerned, this first change is mostly a flush change.

Enjoy,
Bob Wilson

[David Beale]

I have no idea either Bob, but break-in oil usually has lots of copper and Si. That's what is being broken in, the bearings and the aluminum (aluminum is a matrix with silicone for strength), with iron from the rings/cylinder walls. No water is a good result! I didn't see any mention of gasoline content. Perhaps I missed it. That's another thing to watch for. It shows if "startup choke mode" is working properly.

Thanks for posting!

[bwilson4web]

One thing that caught my eye is 'molybdenum' at 651 ppm. I wonder if this might be in the engine assembly grease used when it is put together to minimize the initial metal-to-metal contact:
All About Motor Oil

Another component is emergency lubricants. This is typically zinc, phosphorous, and molybdenum. These chemicals are present in case your oil film completely breaks down, due to extreme temperatures or pressures. These chemicals are supposed to be a last resort defense against metal to metal contact in your engine. Oil companies are cutting back on zinc and phosphorous, as these metals are hard on your catalytic converters. They're substituting molybdenum disulfide, which lowers friction and improves gas mileage. It also causes problems for people with wet clutches, that is most motorcycles.

Then there is this reference that 'sounds too good' if you know what I mean:

Why "NOT" to use moly based engine...... - Tundra Solutions Forum
moly 4 oil,MoS2, Molybdenum disulfide,longer engine life, lower friction,more mpg,more mileage,more mpg's,cool cars,hot cicks,jaguar,honda,ford, chevy,toyota,911,porsche,triump,mg,bmw,mb,lotus,mo re mileage mpg's more mileage mos2. moly, molly, auto m

Molybdenum Disulfide

Without sounds self-serving, "Bobistheoilguy" seems to be fairly balanced and of merit.

Bob Wilson

[a priori]

Originally Posted by David Beale

I have no idea either Bob, but break-in oil usually has lots of copper and Si. That's what is being broken in, the bearings and the aluminum (aluminum is a matrix with silicone for strength), with iron from the rings/cylinder walls. No water is a good result! I didn't see any mention of gasoline content. Perhaps I missed it. That's another thing to watch for. It shows if "startup choke mode" is working properly.

The silicon also could be coming from sand particles related to the original castings.

Does anyone know if the information on viscosity can help to identify the original grade of the oil from the factory?

[dogfriend]

I don't know if you saw this thread:

UOA on OE Toyota oil- 998 miles.

The Si and Moly ppms are comparable to yours although they used Blackstone.

[a64pilot]

If you have ever overhauled an engine, Moly is the thin black grease you smeared on the cam lobes and the bottom of the lifters, very good high pressure lube, you will also find it in CV joints, mechanic slang for it is Moly Be Damn. Hard to pronounce Molybdenum if you are a country boy.

[JATiii]

Oil analysis is a tool. As with all tools, they have one or more specific purposes. Having or using them for purposes other than intended is usually a waste of the price of the tool. As a pilot and airplane owner, I have my oil tested every oil change. I plot the results on a graph.

The main point of oil analysis is to look at trends. Each engine component is made from different metals. Concentrations, or more accurately, changes in concentration of traces of these metals can show what parts are experiencing increasing wear and potential prone to failure in the future. Aircraft engines are routinely overhauled and sometimes have partial or "top" overhauls prior to a complete overhaul. Oil analysis can show when rings, bearings, valves or other engine parts are ready for an overhaul.

Pilots and aircraft owners do this as an engine failure or perhaps an decrease in power could have catastrophic results, e.g, you die. Even if a worst case event does not happen, a catastrophic engine failure usually results in a total engine loss (very expensive). It is difficult to hear the engine clearly in an airplane and minor noises are not often heard so small problems may not be diagnosed by other means.

Piston aircraft engines are routinely run at levels between 70% and 100% of their rated power. At high power levels, engines create and retain more heat. At temps over 400 dF and especially above 460 dF, the metals in the engines become softer and become more prone premature or excessive wear. Add to this that aircraft engines are air cooled, which is not nearly as efficient at regulating engine temperature as a water cooled engine and the concerns with engine heat are increased. These engines are not controlled by computers as auto engines are. Tthe pilot must manually adjust the fuel air mixture to compensate for the varying density of air as altitudes change. Minor mistakes in operation can lead to significant engine problems including detonation (preignition) and overly hot engine operating temps. Lastly, these engines operate in outside air temperature ranges from over 100 to well under -0- dF, often hitting both extremes in a matter of hours.

Cars on the other hand are water cooled with thermostats to help engines reach their ideal operating temperature range more quickly and once warm. Auto engines run at a very low percentage of their rated power most of the time. At lower power setting, they create a lot less heat. Overall, auto engine temps are relatively constant. (When is the last time anyone ever had a car overheat?) Auto engines also have timing and fuel air ratios controlled by computers thousand of times per second, keeping everything nearly perfect. Since most cars are only driven between sea level and maybe 8,000', air density does not change that much. Compared to aircraft engines, cars are downright pampered.

Lots of other users have their oil analyzed for many reasons, but I have never heard of anyone, other than someone selling the service, recommending it for normal passenger vehicles used typically. I'd suggest that it is a racket, just like using nitrogen to inflate tires.

The poster who suggested that you were breaking in the engine and not to worry was correct. The entire purpose of breaking-in an engine is to scrape off and eliminate a lot of these excess metals, get parts to fit better, etc.

If you have a lot of money to spend, go ahead and have your oil tested every oil change and plot the concentrations of various metals. When you see a trend of one or more allows spiking, you will know that you are having a problem. Bring that to a dealer and they will probably do nothing until their computer diagnoses a problem or you have a failure. Of course, if you post the results, you will educate the rest of us.

One more point if anyone is still awake and interested - One more comparison: Most piston aircraft engines are rated with a "TBO" (Time Between Overhaul) of 2,000 hours. Assuming that the aircraft has an average speed of 150 knots, which equals about 172 mph, this would be approximately 345,000 miles. Not bad for an engine so abused.

[a64pilot]

You know, Bob's first sentence was I'm not a great fan of engine oil analysis,
And JATiii, as an A&P/IA, I can tell you your probably wasting your money UOA for your aircraft too.
And hey welcome to PC

[bwilson4web]

In for a pinch, in for pound:


So what have we learned:

• Si leaching is pretty heavy in the beginning and tapers off
• Cu seems a little high but main bearings and bushings have high Cu content
• Al lapping the cylinders
• Fe rings lapping the cylinders

I'm expecting the next 5,000-10,000 mile test will show lower ending numbers for Si, Cu, Al, and Fe. The engine will be 'broken in.' The real test is the viscosity change as a function of service miles. This and possibly the exhaustion of some of the additives will be the real tell for how long the oil can go between changes.

I'm also expecting to use Mo as the tell for how much oil is not drained during a change. A fairly simple formula will let us get a usable undrained oil indication.

Bob Wilson

[JATiii]

Originally Posted by a64pilot

You know, Bob's first sentence was I'm not a great fan of engine oil analysis,
And JATiii, as an A&P/IA, I can tell you your probably wasting your money UOA for your aircraft too.
And hey welcome to PC

Thanks, it is an interesting forum. A64, I gotta ask, do you dislike full engine instrumentation and operating LOP too?

Since my last engine went 1,000 hours past TBO, I feel that I got my money's worth, if only for confidence - a good thing while flying over open water.