Originally Posted by finitetime
Dewatering is not that important in these older engines. I and the people I know with 7.3idi do not dewater there oil at all beyond heating and letting water and food particles to settle out for several days.
This is not good advice. Dewatering is critical to fuel filter life and the health of your IP/injectors and the original posters PSD HEUI injection system. What you describe as heating and settling is in fact dewatering - it does not need to be any more complex than that.
It is a good idea to test your 'clean' WVO for water content. This can be accomplished very easily using the Hot Pan Test. All ya need to do is heat a pan/pot to about 350* and splash a quarter-sized dollop of oil into the pan. Any audible 'crackle' is a NO GO, but we are looking for no bubbles in the oil.
Fwiw, ALL WVO that has been used to cook frozen food will have some water content coming out of the fryers. This emulsified oil does not 'boil off' at the same 212*F that pure water boils at - however, the water is heavier than the oil and as long as the oil is not too viscous it will fall out fairly rapidly (24-48hrs much of the time). This is why heating (110-120* is plenty) expedites the separation process.
As far as a conversion goes, ultimately you're building a heated 2nd fuel system for the WVO and using 3-way switching valves to select the fuel tank you are drawing from and returning to. We use (2) 3-way valves instead of the stock-type 6-way dual tank valve so we can stagger the return fuel when switching back to diesel at the end of the day. If ya switch supply and return at the same time, all of the WVO in the lines and the engine is returned to the diesel tank. This contamination often leads to problems - especially in cold weather. We use coolant to heat the WVO via a heated fuel pick-up (don't heat the whole tank
), heated fuel lines (TIH - tube-in-hose), a heated fuel filter and either a FPHE or a long 'loop' of TIH utilizing a 3rd 3-way valve.
Good luck and keep us posted!