5000mile bad UOA on synthetic

[dB]

quote:

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Originally posted by biodiesel:

This kind of mentality from people that drive 12 qt. sucking Porsche's and other monstrosities like the H2 is why we have to go to Iraq and secure more oil reserves.

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Hey!!! My Porsche 944 only takes 6 quarts and gets around 24mpg. I resent that remark. New 911's and Boxsters can get up to 29mpg highway. I'm not standing up for the H2 or any other "American" monstrosity that wastes gas. I think the Germans do their part to be "green."

I for one do 8-10k mi (or once/year) OCI's with M1 0W-40 on my German cars.

 

[Drstressor]

"The wear tests indicate that the most wear is in the first 3,000 miles so the folks doing 3,000 changes are actually increasing the wear in their engines."

He's not making that up. Read SAE 2003-01-3119. Or just look at the data from the 3MP Oil Life Study. Based on UOA, you accelerate the RATE of wear (ppm per 1000 miles) by changing out synthetic oil too early. The rate of wear metal accumulation goes down after the first couple of thousand miles following an oil change. Nobody really understands why this is the case. It must have something to do with changes in the chemistry of the anti-wear additives as the oil is in service. Boundary lubrication chemistry is not well understood regardless of what you may read on this board. But wear metal data really makes you think.

 

[kickster]

quote:

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Originally posted by Quick_lude:
That's pretty much correct but you forgot to mention the people that are weekend racers/lappers/auto-x'ers. If I go to a couple of lapping events I change my oil regardless of mileage. [/QB]

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Well Last year I raced 10 events plus 5000 miles of Highway driving with AMSOIL. After 15 months of usage UOA passed with flying colors. low wear numbers but there was a little fuel in my oil.

 

[Pitbull]

quote:

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Originally posted by SAFN49:
I've also read that wear metals decrease after the oil has a couple thousand miles on it. Kinda' defies logic, but it's been mentioned enough times that it must have truth to it. Do you suppose the reason may have something to do with the oil filter passing more/larger particles when new, then as the media starts accumulating "stuff" as the miles build up, it becomes better at trapping particles and less "stuff" gets past and back into the oil? This, if it was true, would account for lower wear numbers and may be more filter related than oil related. - or is my reasoning "out in left field"? Regards, Doug.

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Doug that makes a lot of sense.

 

[Roger]

It is not the "improved" filtering ability of an oil filter that produces this result. The authors of the SAE paper theorized that 2 factors influence reduced wear rates as oil ages. One theory is that fresh oil replaces the antiwear film layer of the old oil and metal wear is lower once the antiwear layer is replaced. 2nd'ly, they also felt that there may be some byproducts of oxidation and nitration at high temperatures which aid antiwear better than new oil additives.

While this idea is counter intuitive, the evidence seems to support it. 3MP's study is a real world example. You can also compare reports in the UOA section. Amsoil wear rates per 1000 miles tend to be lower for reports over 7,500 miles than reports less that 7,500 miles. The same is true of Mobil 1 oil.

 

[SAFN49]

I've also read that wear metals decrease after the oil has a couple thousand miles on it. Kinda' defies logic, but it's been mentioned enough times that it must have truth to it. Do you suppose the reason may have something to do with the oil filter passing more/larger particles when new, then as the media starts accumulating "stuff" as the miles build up, it becomes better at trapping particles and less "stuff" gets past and back into the oil? This, if it was true, would account for lower wear numbers and may be more filter related than oil related. - or is my reasoning "out in left field"? Regards, Doug.