I didn't file any claim with Amsoil, as I had heard that it is more trouble than it is worth to get a couple hundred $. Timeframe was 2004/2005, and yes, all the manufacturers were saying the same thing about the SM being just fine for flat tappet and small engines. I know because I called them all. Another interesting thing that I heard from a pretty reliable source (Amsoil dealer) was that during that time period a lot of the oil with different gradings was really SM oil. Because of the backward compatibility of SM per standard, and the fact that there never was a MINIMUM amount of zinc, phos, etc, they could legally put SM in any bottle, almost any grade. SM in an SL bottle was just fine, legally, and even in other older grades. We now know that it was not a good idea. I would not be surprised that other manufacturers did the same thing to use up their stocks of old bottles. I wonder how many folks wound up running SM when they thought they had SL?

Ever since my adventure in pushrod failures, I have followed a few hotrod boards, small engine and lawn tractor boards, and some other late model boards. We all know what happened on the hotrod boards with cam failures. On the small engine boards, it appears there are more posts of oil burning on relatively low hour engines, and lots of bent valves, many from pushrod failures. The later model car boards are very hard to read, but right after the transition, there was a bit of a flurry of complaints of older, higher mileage cars that started to use oil over a fairly short time. Might be coincidence.

I have been hoping someone would be willing to put in the time and money to do a side by side test with SM and SJ to see what happens to modern engines in the long run. I am sure the OEMs have the info, but they aren't talking, as they need the SM for the emissions preservation. Even an oil pump running test would be interesting. I don't think we have a clue as to whether using SM oil will cause oil burning in less miles than older ratings, but you have to be suspect because it is a metal to metal sliding surface. How do you know if it was the oil that caused the problem at 150K that should have happened at 200K?