Edgy01

So what I seem to understand is that all the engine oil goes through the oil filter once every 9 seconds.

I don't see where metal particles will ever have an opportunity to do anything bad.

Clifton

Exactly, metal bits are passing right through the oil filter and thus are not being filtered out. They are too small for the filter element and remain in the circulating oil adding to the abrasion and wear on the engine, until the oil is changed.

Bob Rouleau

Clifton, My GT3 is mostly a track toy. So far we've been talking about metal bits in the oil as a result of the honing process during break-in.

I change my oil more frequently that Porsche suggests because my RS spends a lot of time in the upper RPM register and I am more concerned with the effects of heat and combustion by products. Oil change intervals for the nearly identical 997 Cup engine are measured in hours of track use and are much shorter than those proposed for street cars.

I assume that other aspects of the oil analysis should also be weighed when looking at a track motor?

Regards,

OCBen

Looks like you missed this post:

Fahrer

Originally Posted by OCBen
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 randomly float about within this layer zone and never do any harm to the engine.

There is, of course, still wear. Yes the oil prevents the metal-to-metal contact but the oil actually wears the metal parts down ( like rain and wind wears down the mountains)

OCBen

Using your analogy, and because steel is much, much harder than earth by comparison, it will take billions of years before you see any appreciable erosion on metallic components from the slippery oil.

So yeah, after a billion years it might be time to replace that engine due to erosion from the oil, if you'd rather be safe than sorry.

Clifton

No, didn't miss those at all. Took that post as bad/misinformation.

Depending on how detailed you want to get and which studies you want to believe, engine wear is caused by particles between 5 and 20 microns.

Oil filters do their best, but only grab particles above 30 to 40 microns. The rest of the harmful debris in your oil and causes wear.

If there are abrasives in your oil, then the engine is wearing, regardless of oil layer thickness or float.

OCBen

Show me where you think it's bad or misinformation.

Sounds like you're being unnecessarily paranoid here. That's how engines are designed to work. No machine lasts forever.

If you're expecting to get a million miles out of your engine, then yeah, you should be worried.

Not to give you something else to worry about, but free radicals in your body are constantly damaging your cells, making it impossible for you to live forever.

Edgy01

I thought the earlier post that clearly concluded that something else will kill this car before dirty oil will was the most sensible statement so far. And I thought I was ****.

Clifton

Bob,

Based on the reports I've reviewed for my oil experiments, I would agree that your approach is sound and warranted.

From an oil analysis standpoint, the only difference I've been able to discern between street vs. track motors is that track motors will break down the oil at a much faster rate. And that fresh oil slows the rate of wear no matter how the car is driven.

If you drive the car hard, you simply "use up" the oil faster and reduce the oils effectiveness in preventing wear. Changing that oil before the debris count gets to high, helps preserve and protect the engine.

Example, I found that 3,500 miles was way too long on synth oil for a car that sees track duty (excessive metal counts). Yet on the street, 3,500 miles on the same/car oil was too early to be changing it, i.e., metal counts normal thus no added benefit from changing early.

As others have mentioned, motors vary, so it is my belief that is where oil analysis will help owners determine the proper oil intervals for their specific motor and style of usage.

Clifton

Show me where it is good information that dirty oil that floats between metals is good.

First and foremost, only the paranoid survive. Based on your expert rainbow theories, why even bother changing oil??

We both can agree that oil only has so much life in an engine. That life is based on many factors, including the usage. As such, if changing oil at x interval indicates particle counts in an average wear and tear range, what would compel any logical person to think that going beyond that x interval would be better for the engine??

OCBen

Sorry bud, the onus is on you. You made the claim that my post was bad/misinformation. I never said dirty oil is good for an engine.

Try again.

Not true. The paranoid often make rash decisions based on distorted perceptions, and those poor decisions often have dire consequences, leading to premature death in some cases.

Only the wise and circumspect survive.

Try again.

What rainbow theories you talkin' about? And how to do you make the leap from such supposed theories to the conclusion that one shouldn't bother changing the oil?

Try again.

Go by my recommended oil change intervals and you should be fine.

1000 miles - change oil filter

2000 miles - change oil & filter

afterwards 10,000 mi or 18 mos - oil & filter (non track use)

Clifton

So by default your theories, back by nadda, hold merit on their own because they exist in your own mind - Gotcha. I now understand whom I'm conversing with.

Facts, not conjecture would be helpful on this forum.

Show me how the paranoid local to this thread, is distorting perceptions, causing poor decision making and leading toward premature death.

The same leap that paranoia cause death....

While I partially agree (step 1 & 2), I would take more stock in your recommendation if you backed it with science, instead of guess work.

Unfortunately, 10K oil intervals is bad advice; especially for a sports car. Sure oil can last 10,000, but there are real world studies/examples that indicate that 10K is the very very very upper limit, i.e., end of life. I can understand the need to pinch pennies, but com'on. You drive a Porsche and 9 quarts with a filter is only $80.

jsmirand

This thread may go on for another 20 pages but I think one thing we can all agree on is this: I don't think anyone here will EVER end the oil change debate on Rennlist (or anything related to oil)!



PS. What viscosity oil is proven to be the best oil for 911's in warm climates? And should I start the car and just drive off or let it warm for a minute? And before it reaches operating temperature, is it proven that keeping RPMs below 3k or 4k extends engine life? And what discount should be applied to a garage queen model given the irrefutable evidence that they always develop rms leaks?

John

JW911

And what is the break-in procedure? My buddy told me to just drive like I stole it. And where can I buy Mobil 1 0w40? Can I drive it in the winter? Or should I store it for 5 months?