As promised, I have converted my beastly F250 to run on waste cooking oil. I performed a similar conversion to an ’83 mercedes in 2004 when grease was all the rage. That time I designed my own tank and system. This time I bought a greasecar kit. It took me three months to finish the Mercedes compared to three days to finish the truck. I need to fill it’s 40 gallon veggie tank 10 times in order to make back the $1600 I spent on the conversion. Ironically, the poor fuel efficiency of the truck makes the whole thing payoff faster, in about 6000 miles. I’ve logged 600 already. If you’re into technical stuff, read on.
Greasing Up
Between these conversions I lived in a warehouse in san Francisco that was also home to a company called Got Grease. My buddy Toby ran their operation and collected used veggie oil from all over the city to sell to a biodiesel company nearby. He was a wealth of knowledge on how to collect and filter. In addition a good friend from college, Nathaniel, gave me the low down on biodiesel and veggie oil after having started a biodiesel company years back. For some reason used vegetable oil has always been around me. I guess it’s fate.
Collecting Veggie oil.
The conversion is the end game. Before touching your vehicle consider the impacts of collecting veggie oil. It’s sticky, attracts flies and is a super bitch to clean up. You will, at least once, cover yourself in oil. If you’re careful, you can anticipate spilling and maintain a clean work space.
I am going with a super low-tech, long-time collection and processing system. I visited a handful of restaurants in my area, asked them each if I could have their oil and got lucky with one. They put their used oil in 35 pound jugs by their dumpster. I pick up once a week. I leave these jugs in the sun for a number of days to let the particulates settle to the bottom. Then I pour them through a sock filter and into a 55-gallon drum. I use a 5-micron filter if the oil is pretty clean and filter in stages if it’s really dirty. I compost the little bit left in the bottom of the jug instead of clogging my filter for a few ounces of oil. I leave the oil in the 55-gallon drum for a few more days to continue settle and then I have a small electric pump pull oil from 6 inches off the bottom of the drum and push it through a goldenrod fuel-filter mounted on the wall on it’s way into my veggie tank on the truck. The oil in the tank is clean and clear. No water, no sediment. If you don’t pre-filter, you’ll end up changing your car’s fuel filter frequently and usually on the side of the highway in the rain or snow.
The conversion.
Diesel engines were originally designed (by Rudolph Diesel) to run on peanut oil. Diesel fuel came later. The only necessary change to make to your diesel engine to run vegetable oil through it is the addition of heat to the vegetable oil. Veggie oil is too viscous to burn directly in the engine and needs to be pre-heated to lower its viscosity and thus burn cleanly. Luckily the engine produces enough heat to pre-heat your veggie, so all you have to do is start and stop on diesel (or biodiesel) and reroute some coolant to pre-heat your vegetable oil. In addition to heat, it’s a good idea to filter the veggie separately in the engine compartment. The most basic parts of a conversion include an additional fuel tank with a heater element for veggie oil, a second fuel filter (also with heater element), switches to go between biodiesel and veggie and some plumbing. So far the truck runs quieter and smoother on veggie.
Biodiesel.
I highly suggest converting a vehicle to run on veggie oil instead of making biodiesel. The greasecar kit was easy and straightforward to install and processing used veggie is not that bad if you have a little space. I buy biodiesel from Piedmont Biofuels and they do a great job making it. The unfortunate truth about biodiesel is that you have to employ some pretty awful chemicals to make it. Methanol is not only toxic, odorless and invisible, but it’s also extremely combustible. Backyard brewing can be dangerous. However running on veggie doesn’t completely free you from the diesel/biodiesel world, it does let you rely on it much less and leave biodiesel production to professionals. You won’t mind paying more for biodiesel when 90% of the miles you drive are free.
Environmental Benefits.
At the end of the day running vegetable oil through a diesel engine is still combustion and thus still produces some environmental toxins like you would get from a wood fire. These toxins cause acid rain and smog. They are not cool. But! Veggie oil is a carbon-neutral fuel. The soybeans pull carbon dioxide from the air and convert it to plant material which then gets pressed into oil, burned in my truck and released back to the atmosphere to be sucked up again by another soybean. Running on veggie doesn’t make driving good for the planet, but it does make it much better than running on diesel. You could do even better by growing your own beans and pressing your own oil to avoid the agro-industry soybean racket. But that’s a toughie.
At the end of the day, if I can manage to fill the veggie tank 10 times, this was totally worth the work if only for the feeling of driving on free fuel. It feels so good to kick that switch over to veggie and watch the price of diesel keep going up.
