Sludge Monster :http://yotarepair.com/sludge%20article.html This is another good read when you think of it the oil has a Big job.Contaminants are deadly enemies of an engine. They enter with the air flow and are also generated by the friction of metal against metal. These facts may astound you: for every 100 gallons of gasoline burned in an engine, the following by-products are produced:
I just found this thread tonight even though it looks like you posted it a couple months ago. Wow. I learned a lot just from reading "Car Lubricants: Fact and Friction", and "Improved Fuel Efficiency by Lubricant Design: A Review". Thanks so much for the link!
LubeOiler - wonder where the varnish comes from, how it is defined.
Also, do you have any idea (or source), for the amount of unburned gasoline in carbs vs fuel injection?