PeachParts Mercedes-Benz Forum - View Single Post

coachgeo · #8 03-02-2005, 12:42 AM

From what I gather the biggest advantage to looped fuel return is not heat of oil being thinner fuel for better automization of veg oil pumped into the cylinder/prechamber as much is it is reducing the strain on the IP. The IP does "pull" fuel to some extent as well as pressurize it (push fuel). Some IP's pull fuel more than others such as my Nissan LD28 that has NO FUEL PUMP except the IP itself. Anyway looping the return means thiner oil (closer to viscosity of diesel) is being pulled/pushed by the IP thus keeping the IP opperating under circustances closer to OEM standards. Yea it is hotter but the viscosity is more tolerable. Besides it has been said that hot veg oil acutally cools the IP as good or better than normal operating temp diesel. Thats due to properties of vegoil.

SIDE NOTE: It is not hard to bleed air from a fuel return loop by adding into your return loop a gas car; air bleading, inline fuel filter. These filters are for cars that were found to have vapor lock issues with out such a device. Check you local Cheapo auto part store for inline fuel filters that have 3 ports. The third one you would attached to the return fuel line to the tank. These little buggers bleeds air and a little fuel. I assume you pick the filter shape that when mounted will put the air bleed port as verticle as you can get it. I say this cause the way I assume these filters work is the air in the filter travels upwards vertically. Anotherwords the fuel is usually pushed out horizontaly while the air (and a little fuel) exits vertically.