Thanks for the link fellas. I just got around to checking it out. I just got done dropping my baby off at Brown and Brown in Mesa for a clutch R&R. (that's remove and replace, NOT rest and recreation)
This is stock clutch number 2. I hate to think how hard it's going to be to keep one in there when the warranty runs out and I start to mod her.
Ok, here are my concerns. First, let me quote from
http://neptune.spacebears.com/cars/s.../oil-life.html
I picked this test because they used Mobil 1 in a 2002 Camaro with an LS1. That's close enough.
They start out by saying:
begin quote- "Are you going to trust a $5,000 engine to $40 worth of motor oil that supposedly can go 25,000 miles without a change?! We sure as hell won't! Yet the claims continue to intrigue us. Honestly, we hate oil changes, and if we really can run our oil to 10,000 miles without harming the engine, then we will. Unfortunately, the only way to be really sure that everything is going okay in there is through oil analysis -- and at $20 a pop, you might as well just change the oil." -end quote
Precisely my argument.
They go on to say... begin quote- Finding objective analysis data is tricky -- we've noticed several purportedly independent oil analysis labs actually have very cozy ties with one of the competitors in this study. That makes it difficult to accept some of the online oil analysis results as objective! -end quote
Again, I agree. Their DOE (design of experiments) was reasonably well thought out, but I would done a few things differently myself. Allow me to make some comments.
Here's what they tested:
# Viscosity: This is the SUS viscosity at 210 degrees. It is the standard SAE viscosity measure; SUS is the unit of viscosity. This value should remain within its grade, or plus or minus 20%, whichever is greater.
# TBN: The Total Base Number. This is a measure of acid-combatting additives. Oil is essentially expired once it reaches a TBN around 2.
# Insolubles: This is the percentage of the test sample consisting of solids. Solids are always bad; the value should be less than 0.6%.
# Wear Metals: The presence of wear metals is a contaminant and the rate of accumulation is an indicator of the oil's protective condition. The exact values representing oil change time is rather subjective; we use Blackstone's conservative guidance in conjunction with other industry experts. Iron, copper, and lead are normally the ones to watch.
Insolubales are what bother me, and this last category is where my curiosity is piqued.
They say:
begin quote- Also, there's the analysis of elements expressed in parts per million. Some of these elements are indicators of engine wear, while others are additives in the oil. For any of these, the presence or absence of any element is less important than how the values change over time. -end quote
That last sentence I feel is of great importance. This, I noted in another post, caused me concern. The levels of insolubles went up for awhile, then dropped a little and stabilized until the oil was changed. That got my attention. Why would they do that? My theory is that engine wear is still taking place, and at even a more accelerated pace due to the levels increasing, but they are being deposited into places where the engine is wearing. Again, I'm not an ex spurt, I'm just curious is all. The oil guys have a good rap with lots of technical sounding bs, but does it really make sense?
Now. The site goes on to say...
begin quote- Engine wear actually decreases as oil ages. This has also been substantiated in testing conducted by Ford Motor Co. and ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119. What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it. -end quote
Now Charlie and you other slackers with dirty engine oil, j/k LOL! if you're still reading, before you jump up and start hi-fiving, let me quote from another site. I haven't paid to read the study mentioned above myself, but I will if I have to. This guy has and he says...
http://swspeed.com/printthread.php?t=740&page=1&pp=15
begin quote- dwtalso 08-01-2004 02:03 PM The full title of SAE Technical Paper 2003-01-3199 is "Antiwear Performance of Low Phosphorus Engine Oils on Tappet Inserts in Motored Sliding Valvetrain Test". I have this paper and have read it. The results and conclusions have absolutely, completely, and utterly nothing to do with oil change frequency. You cannot change your oil too frequently (within reason) and this paper does not contradict this.
The primary purpose of this paper was to study the wear characteristics of low Phosphorous oils. New federal regulations for emissions require stonger catalytic converters and P reduces catalytic efficiency ("poisoning"). The paper was trying to determine if we were now going to take a step back in terms of wear in order to save the ecology. That answer, by the way, is no. The current low P oils have enough new additives to provide good wear characteristics.
A secondary purpose was to evaluate wear characteristics in fleet vehicles using low P oils. For this test they used fresh oil first, then drained the oil, and then refilled the system with used oil. This simulates what most fleet environments do. They found that the used oil provided better wear characteristics than fresh oil, perhaps because the additives have broken in.
So, if you clean the oil you drain from your car yourself, by all means put that oil back in. It's better. However, this has nothing to do with frequency of oil change. If you change the oil every day you might have more wear because it takes some time for the anti-wear films to form. But if you changed your oil every 500 miles, you would be doing your vehicle a favor. -end quote.
FYI Charlie, Walmart has the best price on Mobil 1.
