I've never run Diesel engines. A 4 2 4 break is usually a term we used with Fox Stunt 35 engine. Adjusted thru the needle valve assembly. When the plane is level it runs like a four cycle a little rich then when you raise the nose of the plane vertical it leans and runs like a two cycle, hence 4 2 4 break. Best accomplished using 10% Nitro 28% caster. Don't know what model engines your running. So From model engine to model engine your tank location and engine set up can compromise thus theory of 4 2 4 break. Don't really think a diesel can be set up for this. Hard to say with no diesel experience.