quote:Is this the test you are talking about? Link If so the OCI were 7500 miles for the dino and 15,000 miles for the synthetic. Its kind of interesting but does not necessarily duplicate real world with thousands of cold start conditions. Outside of valve guide and valve seals problems. One of the problem areas high mileage motors seem to suffer the most in the short block is usually not so much wear. But rather carbon fowled piston ring groves. Eventually leading to stuck rings. If any of the rings stop turning there roughly five RPM things tend go downhill very soon. This is one area that synthetics seem to strut there stuff from what I have seen on cars and dirt bike motors. Dino oils always seem to accumulate carbon in the ring groves in higher mileage motors while synthetics seem to cleanse this area fairly well. Hopefully the newer SM dino oils will narrow the gap in this area of deposit accumulation.
Originally posted by Matt89: I seem to recall a test that Mobil did...Mobil1 vs. a dino oil in engines run on a dyno with the same OCI. Apparently after 200K miles of simulated driving the dino-fed engine had significantly more wear and varnish, the oil changed viscosity etc etc. But the fact that it went 200K miles kind of begs the question, doesn't it? I'm sorry I don't have a link...I read it when I first became "oil aware" circa 2003.
quote:The main thing that I've seen out of synths is either in service longevity or performance in marginal circumstances. Othewise ..they lubricate as good or not as anything eles in common service. That is, sure, if you're starting in -30 (it doesn't have to be that cold) ...or hitting 150C as you peak out in 3rd gear at the track ...then a synth shines ...but of you're just using it for 15k vs 7500 for a contemporary dino (adjust OCI to the level of paranoia that you're currently at) ..then I don't think that there would be much of a difference between the life of the two engines. ....or said another way... under something real conservative ..like 3k/3m ..all you will do is spend more money to see the car hit the junkyard with a perfectly lubricated engine. There's no magic oil ...well ..maybe now they're all magic
Originally posted by carock: There are back to back synthetic vs dino tests reported by the Society of Automotive Engineers for diesel engines. Some are done by the oil companies and touting their products and others were paid for by the Army. All the tests show synthetics to be better when actually measuring engine wear, not UOA's. I am no expert, but I think measuring engine wear with UOA's is a flawed technique.