Clifton

Although I suspect your question is loaded, the answer is no. Anything mechanical is destine to wear. As such there will always be base level traces of said wear.

These reports are helpful in that they let you compare your oil sample with oil samples taken from similar engines. Is it perfect, no, but will help you better understand the health of your mote, absolutely.

Clifton

If it is known that on average a 3.xL motor yields 4-ppm aluminum based on collected oil samples, then I think it is a very safe to say 25-31ppm indicates an issue/high wear. If the levels of aluminum drop back down to 4 due to more frequent oil changes, then it is very clear that reduction of aluminum wear was a benefit of shorter oil intervals.

As oil begins to fail/breakdown, metal ppm counts will rise. High ppm counts (over uni-average) is an indication of additional abrasive in the oil and that will actually accelerate engine wear only to continue an even higher ppm count. Of course this is assuming there is not something more sinister failing within the engine.

I use Blackstone reports to find the true sweet spot of oil breakdown according to how I use the car. In other words, how long can I let the oil go and stay within the normal wear averages. On my 2003 M3, city/highway driving = 5,000-6,000 mile intervals. On my 1998 M3, track duty = 1,500 - 2,500 mile intervals. The GT3 - we shall see....

mdrums

Clifton, thank you for posting your reports.

997, esq

This is certainly possible, but there is no proof the high levels are likely to do anything harmful to an engine. For all we know, 100 ppm causes no harm though it is 25x average. My skepticism arises from the fact Porsche doesn't recommend more frequent changes, and that it has some pretty serious brainpower and knowledge behind its recommendations. While it is probably true that Porsche would want to keep it avg. cost of maintenance low, I don't see that leading it to recommend oil change intervals likely to cause significantly increased damage to engines. The loss of customer goodwill, and repairs that Porsche pays for (under the terms of warranties or otherwise) would probably lead to Porsche making safe recommendations. But, that said, if this gives you comfort, I understand. It's interesting data; I'm still just not sure what it means.

rickmdz

I'm not an engineer nor a chemist. It's hard for me to understand this assumption you make. I think in this equation are few factors left out, most importantly, time or miles factor or is it compared to engines with the same number of miles and/or hours of operation? Then wear is dependent on use, not the same on an engine used near redline vs low rpm's. I think the question is if those contaminants alter the lubricating properties of that oil, and that's something that synthetic oils are very good at (keeping those properties hence the recommended long change interval )

Regarding dark oil, that is what modern oil is designed to do. They have detergents that clean the engine preventing sludge.

Not trying to be smart a--, just asking...

jimjoe997

Particle size is an important consideration, and the report does not give information on this.

For example, if these metal contaminants average 10 microns in size, and typical engine clearances are 100 microns, I would expect the metals to do little damage - they would flow around with the oil. On the other hand, if the particulates are comparable in size to the engine clearances, then there would be more abrasion.

I would expect that engine designers have thought this through. "If engine clearances are X, then we should specify engine oil filters that remove particles greater than Y to minimize engine wear." The manufacturers should know what X and Y are.

Particles much smaller than Y may be indicative of engine wear, but they do not necessarily contribute to additional wear.

The test lab should also be asked for a particle size distribution, but I suspect that this is difficult to obtain at the concentrations we are talking about.

ltc

God, how I love oil discussions on Rennlist...I've yet to see one resolved.

Bob Rouleau

Boo - No, if you look again, my post refers to transmission fluid in response to a prior post which observed that Porsche suggests two year change intervals. Curiously, the 996 GT3 Cup car manual suggests changing the transmission fluid at ten hour intervals. The transmissions in the Cup car and the regular GT3 (996) are identical. Both are somewhat fragile. I also observed that my transmission fluid was a very dark color when I changed it. There are no combustion by products in the gearbox that I know of, on the other hand, when driven hard on a race track, the fluid gets hot.

As to engine oil change intervals, I change mine every 15-20 track days. I have no empirical evidence to prove that right or wrong but it makes me happy.

Regards,

p-cardriver

Thanks for posting the analysis reports. Its interesting to see both the data they report and the comments, especially on your car with more samples.

I think it would be very helpful if they could provide both the mean (average) and std. dev. of the values for each engine (perhaps on a web site?), and of course I'd want to know if engines with higher particulate values (say mean plus 2 SD) tend to have higher wear. Thus a series of leak-down or compression tests would complete the picture (well, for now).

None-the-less, having any data is helpful and this thread is a great start!

RonCT

I do find these things helpful. My "gut" has always told me to change the oil after break-in. So, my process is pretty much stick to the BI process (slightly modified to incrementally increase RPM as you approach 2k). Then once a year, which for me ends up being about every 7-8k (just so much driving you can do from mid April to mid November). So, first Spring the car is new, break it in, change the oil & filter, then enjoy the remaining 5-6k until late fall. Oil change in Spring, repeat every year. Brake fluid every year and I guess Tranny as well (haven't gotten there yet - for some strange reason I've been getting a new one every year - but not this time, this 09 C2S is the keeper).

I wouldn't do this for normal street driving, but with DE use it feels right.

LlBr

FWIW, AFAIK, about oil analyses: apparently they don't mean much unless they are done to the same engine and at regular frequent intervals.

The _comparisions_ of _many_ test results recorded over time tells what you want to know: tells if something is going wrong or if things are nominal with that _particular_ engine. Works great for regulated structured engine maintenance programs for the aviation industry.

On another matter: I'm tending to trust the engineers to spec oil filters to remove the bad stuff (particles, burrs, shavings) resulting from break in of our car engines; synthetic oil does not break down. Of course I always change break in oil 50% sooner than recco'd and then forget about it except once a year.

Dadio

And the debate rages on .

OCBen

You guys really need to trust the Porsche engineers here. They really do know what they're doing.

The thing to keep in mind that many of you may not be aware of is that an engine is designed such that the moving components never come in physical contact with one another, even though they are mated and connected to one another.

The cam lobe that is pushing open a valve never comes in physical contact with it - the two metal pieces never physically touch each other - even though force is transmitted between them. There is always a thin barrier of oil separating engine components. The thickness of this oil layer is a known quantity. Particulates that are smaller than the thickness of this layer will float about within this layer zone and never do any harm to the engine.

The good news is that the filter is designed to remove all harmful particulates. It really is a science and the power plant engineers know it better than anyone else. So you really need to trust them.

Tbred911

this is a long answer but the short answer here is no.

on an engine that burns no oil you should see less silicon and metallic bits after break in and as mileage increases... I have a new 3.4 and am doing blackstone as well... I didn't even bother sending the oil we drained after the 1st 1,500 km cause I have a magnetic drain plug and noticed all the super fine micro shavings that were stuck to it... I've changed the oil 2 more times and visually nothing was present on the magnetic drain plug like there was in its first interval... and percentages of metal is decreasing to safe and normal levels....

I think the oil analysis is great for seeing a rise in critical metals that indicate irregular wear in the motor and possible catastrophic failure...

I use Mobil 1 5W50 and my analysis shows that its good for 10-12 hours of track time; my average track day is 2-3 hours total 5 x (25-40min) sessions

this also includes lots of street driving... so 12 hours track driving + about 5,000 km on street driving

and the TBN of the oil is 7.5 - still good according to blackstone but by the 12th track hour 7.5 is the lower limit for me.

After 11,500 km on the oil blackstone wrote:

Nothing potentially problematic turned up in this second sample from the 3.4L in your Porsche.
The only metal still reading high was copper, which is most likely from continuing wear-in at brass or bronze
parts. Silicon dropped and now mirrors the level in averages, showing the excess sealer, etc has pretty
much washed out of the oil. The TBN for this sample read 7.5, which means that lots of active additive
remained as of the sample date. The viscosity of the oil read normally for this oil type and grade. No
contamination found. Try 9,000 km on the next oil change.

Leader

While there's a lot of apples-and-oranges going on in this thread, it really all comes down to - who do you believe.
I've always tried to evaluate the advice I get (on any subject I might not be well-versed in) based, in part, on the agenda of the person giving the advice.
Just because a carpenter might recommend a hammer to solve every problem, doesn't mean the discussion has to end there.
As quantifiable as these "elements" in oil may be, what the amounts mean to the way you drive is still a matter of interpretation. It's not a fact/fiction dichotomy.
Of course, I could be wrong. It's happened before (earlier in this thread, apparently).