quote:B&B Autoparts in Redmond, WA (just down the street from Microsoft and Nintendo headquarters). Not sure if you have them in NY, but that price only applies if you buy a whole case (like I'd buy anything less ). As for your piston slap, does it go away when the engine warms up? If so don't sweat it. I know that hypereuretic pistons like those in my LT1 Trans Am, and GM's newer LS1/LS6 engines are designed with tolerances that run a bit loose when cold, but once the engine is up to normal operating temperature (and the piston slugs have expanded to their heated size) the piston-cylinder tolerance is much tighter and the slap dissapears. It's most noticeable in LT1/LS1/LS6's on cold days. If you think this is strange, just remember that piston-slap was even worse when manufacturers used regular cast pistons and the swelling was more pronounced (and hence the tolerances had to be even greater so a cold engine was LOUD). As for the zinc ruining cats/O2's I was suprised to hear it (although seeing how heavy metals can ruin a cat fairly quickly, it isn't much or a stretch to see the same happen with a zinc-aromatic). I think I first read about it in Cycle World magazine (or a similar bike rag). They were discussing the new BMW cats and O2 sensors used for emmisions and EFI. To protect the BMW's new components, only new-formulated motorcycle oils could be used that had decreased levels of zinc. Since bike oils need to protect to 12,000RPMS and such they explained that a car-oil would be a bad choice, since bike oils typically have much higher levels of zinc in them. The new formulations would lower the zinc to an acceptable level (I wanta say 3%, but it may have been 0.3% this is all from memory) and increase other anti-wear additives to compensate (moly perhaps?). Seeing how Amsoil brags about actually having high levels of zinc, and I don't know of anyone with problems, I can only think of 2 things: either 1) Amsoil isn't very volitile in car applications (maybe they formulate it this way, or maybe a car engine is just less of a cooker than a high-performance bike engine/cooling system) or 2) maybe Amsoil's higher than average zinc content is just in comparison to other CAR oils, but is still lower than the emmissions-obilivious and anti-wear-demanding motorcyle oils? hmmm... think I'll dig around for that article this weekend. I don't read many bike magazines so it may be easy to locate.
Originally posted by Bror Jace: I think the jury is still out and exactly what will and won't foul an O2 sensor. Amsoil claims that oils high in zinc dialkyl dithiophosphate (ZDDP) will not harm catalytic converters if their volatility is very low (I forget the percentage they cite – 5%?). I guess low-volatility oils tend to stay in the crankcase and less of them make their way pass the rings and into the exhaust. Sounds reasonable to me. This is wear of the piston skirts and is considered normal wear for this engine. SteveinSeattle, where did you find Red Line for $5.50 per quart?