Of course, if one drives it and uses it, no short trips, gets it up to full temperature(no 160 degree or missing thermostats) for at least 15 miles, like it was designed, you should not have sludge in the pan to start with.
Ed
What about engines designed/destined for use of non-detergent oil? Would there be no "sludge" in the pan, even if the engine is run as you described?
I'm just being a jerk, Ed. Very few stovebolts are run with non-detergent oil these days.
