[screamingchief]

If you read the links that have been posted it explains why this is so,the part on multi viscosity oil should be an eye opener for all,this has to do with the amount of friction modifiers added to gain a given rating,the 5w30 use less modifiers to gain thier rating than say a 10w40 making it much more "stable",the greater the spread between the lower and upper weight the more modifiers needed to be added.This is why diesel engines pretty much use 15w40,which is awesome oil for warmer climates in a gas motor,but sucks in cold weather,I found this out when I lived in wisconsin,had a mercury linx wagon that had crank noise on start up,so I used 15w40 and it cleared up,then one dec. morning it got cold,really cold, and it would hardly turn over, the battery was toast and I had to push it in the garage,turn on a heater and change oil to get it to start.Hell they use 5w30 in nascar motors and it'll live but pretty much this is something we each choose on our own,I will continue following cam co.s break-in recommendations to the letter as I have not had a cam failure yet (knock on wood) and after break-in use the oils I always have.