For my personal use in my diesel and gas engine I use Delvac Elite but a friend of mine who is a engineer but far from been a beans counter one try many test on his very modified CRD engine like mine (Centrifuge oil filter)
He use Rotella T6, Mobil 1 and many brand syth oil, the one who get the best result was the Amsoil with Zinc I can't find that oil yet otherwise I run all my equipment with it.
This one in the CRD...
http://www.amsoil.com/shop/by-produc...?code=AROQT-EA
This one for lawn mower?? (Not tested yet)
http://www.amsoil.com/shop/by-produc...tic-motor-oil/
The secret name additive is "Zinc" the one your wonderful EPA green pot smoker ban ...