I have been using synthetics since the mid-90's. I use Mobil 1 & usually change my oil at about 5000 miles, but sometimes I go longer if it looks good and the weather is cold. I also use Briggs n Stratton synthetics in my lawn/yard equipment. Air-cooled engines will burn conventional oil in the crankcase, but synthetics are less prone to burning, (dont turn nasty brown easily). The oil molecules are more uniform in size, unlike traditional oils, and it also has much less wax, which leads to sludge buildup.
Met a guy at Lebanon Dragway (NY), who was talking about the advantages of synthetics over conventional oils. We went up to watch my buddy's Dad and his pals run a couple Chevelle wagons. We were hanging around in the pits near the "****" & a guy was trying to sell people something called "Synthoil" IIRC. Was around 1994 I think... I was just out of high school. It was damn expensive stuff too... wasnt long after that, I was told by a friend that the new Pep Boys store was selling their own brand of synthetic oil... I ran it in my '72 Chevelle Malibu 350 and I did notice a difference in the engine right away. Ran a lot happier and I picked up a little mileage. Downside was that my rear main started leaking. When I drained the oil to drop the pan, there was a lot of sludge that came out... the synthetic free'd up 20-odd years of crud. After that, my engine ran cooler for longer periods, and the oil in the crankcase didnt look burnt after 1000 miles. God only knows where the gunk was free'd from, but it sold me on the stuff. I used Pepboys and later Sunoco Oil Synthetics... I was a big Sunoco fan.. they all sold 94 octane and two stations in my area sold 103 octane ($3.00 a gallon in mid 90's vs $1.05 for Sunoco 94 octane). Not sure what happened, but they ditched the high octane fuels and franchised out their "A Plus" stations... after a few years, there were very few Sunocos left, so I went to Mobil... used Mobil's tri-something synthetic and then Mobil 1 when it replaced the older stuff, plus I primarily use Mobil Gas since the mid 2000's... and occasionally other Tier 1 fuel makers when I cant find a Mobil.
