Bruce, your design sounds like a good one, but I must say, with all due respect, I believe this is an un-founded myth. First, I don't believe that this is a common modus operandi for passage makers. Secondly, I have experience with the worst-affected Diesel if operated in this fashion, the venerable Detroit 71-series. Despite operating half-time at no-load idle speed, we did attain 12-15,000 hours between overhauls. Pretty good, but that's about half what can be expected with 4-stroke engines in the same service; in fact we did go 30,000 hours consistently with Cat D353s. Regards, John "Seahorse" > ... the under-load problems caused by operating a single larger diesel at low RPM. **************Play online games for FREE at Games.com! All of your favorites, no registration required and great graphics b check it out! (http://pr.atwola.com/promoclk/100000075x1211202682x1200689022/aol?redir= http://www.games.com?ncid=emlcntusgame00000001)