Downward Spiraling: Vegetable Oil Conversion

Our beloved 1987 2.1 liter Volkswagen Vanagon Wolfsburg Edition went belly up during spring break. So this is the prefect time to drop in a 1.9 liter turbodiesel and convert it all to run on vegetable oil. Yep, we are going 2/3 veggie (we still have a CJ-5 Jeep that I drive to work each day, which is only about 5 miles, so WVO doesn't make sense).

I have been thinking (Serenity might call it obsessing) about the conversion since then. I don't want to pay $4,000 to have someone install something that I think I can do myself, so I plan to install it myself. I also don't want to pay for engineering that I'm not sure either 1) fits for my climate or 2) doesn't make sense economically so I don't want to purchase a kit and am designing my own system and schematic.

However, I am not a mechanic, so I found a local guy named Mike who does engine swaps with Vanagons (Subarus, TDI, etc.). It is obviously a specialized trade (swapping a gasoline engine for a diesel). The actual vegetable oil conversion will be done at Mike's shop, but only with his guidance :)

I have thought about this conversion a lot lately (I do my best thinking at 3am right after Luci wakes me up, and in the shower), there is a lot to think about: tank placement, heat exchangers, waste coolant heat, 3-way solenoids, injection line heaters, etc.

Basically the theory goes that vegetable oil (VO) burns similar to diesel once it is heated to around 180 degrees which changes the viscosity to be thinner and burn more complete.

“The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time.” - Rudolph Diesel (1912)

So, heat the VO on it's way to the injectors and you have a fuel that cuts emissions by around 85% and can be free if you know where and how to collect it. Along with heating the VO you must start on diesel (don't want to force cold VO into the engine and injectors) and purge the system of VO by running diesel through it before you shut it down each time, which takes about 30 seconds although it varies depending on how well designed your system is.

OK, so let me explain my design. Starting with the VO tank (which will be under the rear seat and will be 20 gallons giving us a range of over 500 miles per tank) the lift pump pulls VO out of the tank and pushes it through a "VegTherm" which can heat the VO to temperatures near or above 200 degrees depending on climate and time of the year. If the temperature of the VO reads excessively high during the summer months I will have a manual switch that turns the VegTherm off. Next the VO travels through a coolant heated filter head and into the filter which will be heated with a WVO Designs 12 volt electric filter wrap. From the filter the VO travels to the 1st of two 3-way solenoid valves where I can control from the dash whether it pushes out diesel or VO. A temperature sensor will inform me if the VO temperature is too high before it goes into the fuel injector lines which are heated with 12 volt electric wraps. What fuel is not needed at the injection pump is then sent back through the return lines either to the diesel tank or looped back into the VO lines depending on what I have selected on the dash of the Vanagon.

Here are some pictures of Mike and I as we dropped the old engine out of Wolfy. The 1.9 turbodiesel engine should be installed this week or next and then we can get to work on the VO system.