http://journeytoforever.org/biodiesel_yield.htmlthis refers to yeild from various veggie oils. It starts in Kg per Hectar crop yeild, but it also identifies the major oil crops, and the cetane number, as well as other fuel properties of each. It's a good starting point.
Unrefined veggie oil has glyserine and other constituents that are harmful to diesel engines. Some engines tolerate them better than others. Listeroids with precombustion chambers seem more tolerant, although the sellers of GM90 engines may want to comment as well. Some modern engines pack up for good after running for as little as 20 hours on pure palm oil.
Valve and ring problems are common, and more frequent service teardowns for cleaning would be expected. On the other hand, operating expenses would be a whole order of magnatude lower if it works!
Third world scientists are vitally aware of the benefits of running engines directly on fresh squeezed oil. Research on which engines run best, as well as which oil types etc will work is an on-going afair.
Our Listeroids could be at the forefront of a second technological revolution
