[RustyLugNut]

found in current diesel engines do not work safely with VO (vegetable oil ) because of the reasons listed out by Oil Pan, Rooster and niky.

The low pressure inline pumps found in Pre 1996 Mercedes diesels, Dodge Cummins VP7100 equipped 5.9L and old Cummins 855's easily survive a failure of your VO heating system. I have seen some abusive installations on these engines ( poor or no heating of the VO and insufficient filtration ) and yet the pump survives with no apparent damage. I have seen VE pumps and late model high pressure pumps fail mechanically within seconds with VO. The above listed engines are not the only ones that can run on VO successfully, they are just the ones I have had experience with. A low pressure (2000 psi) inline pump seems to be a necessity to cover for failure modes in running your VO.

As Rooster pointed out, indirect injection is an advantage. More complete combustion can occur within the pre-chamber which helps minimize the problem with VO in direct injection applications - the clogging of rings and lands with polymerized VO which could come about for a myriad of reasons.

Our 1996 Dodge Cummins and a 1996 Van equipped with the Mercedes 606 diesel both have had episodes of ring gumming when running on VO even with proper VO filtration and heating. The variability in our used oil sources is the likely culprit. Constant water/methanol injection has eliminated the problem but the volume of fluid used on a long range over-the-road tractor/trailer could be problematical.

The ideal tractor/trailer would have a low pressure inline pump and indirect injection. I do not have a broad enough experience base to have seen one. Maybe someone else can point you towards a likely solution.