From Journey to Forever:
"The downside is that straight vegetable oil (SVO) is much more viscous (thicker) than conventional diesel fuel or biodiesel, and it doesn't burn the same in the engine -- many studies have found that it can damage engines."
"Along with many others, especially in Europe, we think pre-heating the oil is still not enough to ensure that it will combust properly inside the engine. It needs a complete system, including specially made injector nozzles and glow plugs optimised for veg-oil, such as the professional single-tank SVO kits from Germany."
I did a great deal of research before deciding to take a pass on SVO and build a biodiesel processor. After MUCH research I decided that I did not want to take a chance with my (expensive to replace) diesel engines.
Just my $0.02 . I am sure that you will hear from folks with differing opinions. Before you decide, contact the manufacturer of your engine and ask their advice....