quote:My post was about proving Engine Design has a lot to do with sludge. The Geeks at B&S design these little engines for abuse. The tolerances are loose, the oil galleries are as big as the Lincoln Tunnel, and they are simple. These little engines are designed to see severe service, that no vehicle engine will ever see, unless you convert you caddy to a lawnmower.
This should clear up the small engine question
Just thought I should add that small engines don't have high tech sophisticated emission systems like cars do... further stressing the oil. Car engines are also plagued with short trips,incomplete warm ups,condensation and so forth that all contribute to oil oxidation. Small engines will run hot and burn off VOC'S ,condenstation,and fuel intrusion. There exists no possible coolant intrusion into the oil in those small air cooled engines to boot.
The small air cooled engines do run the oil to higher temperatures compared to water cooled engines which can pose another set of possible issues in some cases!!