It has unparallelled film strength both hot and cold and maintains good viscosity for sealing purposes at all times. Much less than this seems to affect engine life over the long term and gives increasing sealing problems as engines become more worn, particularly in diesels used for combat where dirt ingestion is a fact of life. One difficulty with castor oil is that it is insoluble in kerosene. Hence in part the reason for our next ingredient. It has a relatively low calorific value and tends to detonate unpredictably rather than self-ignite smoothly and cleanly.
Detonation places enormous stresses on engine components, and is to be avoided at all costs.
Ether is also extremely volatile and evaporates readily. So diesel fuel should always be kept in a sealed container except when being transferred to a field container or to the model. Finally, ether is an excellent solvent and is highly reactive. It can also form highly unstable peroxides if exposed to light for any length of time. The kerosene content greatly reduces the tendency of ether to detonate, so we do have some leeway to play with.