Editor’s Introductory Note: The recent spike in fuel prices prompted me to re-post this very practical 2018 article from the SurvivalBlog archives. – JWR
It has been said that necessity is the mother of invention. Needing fuel for their war machine lead Germany to invent and perfect the diesel engine. It was designed to run efficiently on vegetable oil, and they do to this day.
Circumstances forced me to make a move from my East Texas home to the deep Southwest. It was a slow, long process of gradually moving my stuff and my wife to a new homestead. I commuted from Nevada to East Texas for almost three years, at least monthly. Growing up farming, ranching, and trucking, I had a lifetime of experience with diesels, how they work, and what it takes to keep them running.
Experience Running Waste Vegetable Oil Fuel
It was the days of $4.00 a gallon fuel that set me on the veggie trail. Now, after twelve years of experience running waste vegetable oil (WVO) as fuel, I have learned a few things, which I will now share with you.
I have run Mercedes, VW, GM 6.2, Cat 9L, Ford 6.9/7.3, Ford Backhoe, Kubota tractor, and Gensets, China diesel, some NA, and some turbo. There is no difference on a very cheap and easy to do system.
My Diesels on WVO
I have Mercedes 240D and 300TD engines that run on WVO. I had a bus with a 9 liter cat v8 that I used to commute back and forth in, serve as a place to sleep, and for hauling stuff from Texas to Nevada. A 1982 3/4 ton Chevy 6.2 did well on WVO. I setup a 1991 F250, 7.3 Turbo with no problems. Also, I had a 1981 VW pickup diesel. My 1984 F250 6.9 NA pulls a four horse trailer with 120 gallon tank in the bed, and another 1984 F350 6.9 NA with 12 ft box and none miss a lick. Beyond those, I have a Ford diesel backhoe, Kubota genset, China diesel genest, Kubota utility tractor, and my new truck, 1988 F350 dually crew, 7.3 turbo to haul my gooseneck trailers for my stuff, and my new project is my school bus, 8.2 Detroit turbo, 5 spd/2 spd axle as my new motor home. Obviously, I like diesels, and they all do great on WVO.
Purge With Diesel
I always run a dual fuel system starting on diesel using engine coolant to preheat WVO and switch to WVO at 100 plus degrees F. When I shut down for the day, I switch back to diesel to purge the system of WVO. Some folks don’t purge, but I just don’t want WVO left in my pump or injectors for any length of time.
Where WVO Comes From in Volume
Restaurants are where WVO comes from in volume. I have no advice on collecting. Live and learn. I collect 800 to 900 gallons at a time in 55 gallon barrels. It takes me about four hours to collect, and then about two weeks to get the WVO ready for my diesels.
Emulsify
I transfer WVO from my hauling barrels that are heavy and in my trailer into 55 gal barrels in my storage area. I only put 40 to 45 gallons in each barrel. I top off the barrels with water! Sounds crazy? Ya, maybe, but my ’81 240d has over 50,000 miles on WVO with no problems. I then use a pump, suction on bottom of barrel, discharge in top of the same barrel, and I recirculate that barrel for however long it takes to totally emulsify the entire barrel until it looks like hand lotion. This process might take 15 minutes and up to maybe near an hour, depending on the WVO and temperature.
Stratification
Once emulsified, I just let it sit for a week or so. I use white barrels so I can see the stratification of the liquid in the barrel. What I end up with is black gunk on bottom, a layer of water, a layer of animal fat like lard, and on the top of all of it is beautiful, clear, clean veggie oil that looks like honey, usually about 40 gallons of fuel.
Filter Into Ready Fuel Supply Barrels
I then pump from the top of the “honey” through two Walmart Pur water filters. First, I use the 20 micron filter and then a 10 micron filter. Then, I run them inline into my “ready fuel supply” barrels for use.
Left Overs
What about the junk left in barrel bottoms? I emulsify the left overs, pump it into my “junk” barrels, and let it accumulate. By the time the barrel is full, you can pump about 15 gals of “questionable” honey into a barrel with fresh WVO and process it again. I pump the water from the bottom of the “junk” barrels. It will have sugar/salt and other soluble cooking ingredients in it. The black stuff in the bottom is from coatings on the stuff deep fried. The white stuff is animal fat. I’m sure if I think about it, I will find a use for the animal fat. My chickens like it.
Fuel System on Diesels
How I set up the fuel system on my diesels is inexpensive and easy. Two separate systems combine to make your diesel WVO usable.
WVO Preheat System Parts
For the WVO preheat system, you will need some heater hose, hose clamps, and a couple T’s, two ball valves (so you can shut the coolant off from the heat exchanger; it’s not necessary but lets you isolate your engine’s cooling system) to set the system up to preheat the WVO in combination with a heat exchanger, Ebay 20-plate Copper Brazed Heat Exchanger 5″x12″ , WVO SVO, Boiler, Wood furnace.
Dual Fuel System Parts
The dual fuel system is also very simple, once you wrap your brain around it. You need a fuel tank for WVO, fuel line, (I use the red air hose from Hodepo for fuel line; it works!), a low pressure 12v auxiliary fuel pump, two two-tank fuel switch valves,(I use manual marine brass valves or the Ford two tank electric valves), and an auxiliary 10 micron fuel filter.
Install
To install these systems, put the WVO fuel tank wherever it fits. At one time I had a 55 gallon barrel in the back seat of my 240D, so I was good for 1500 miles. Install the auxiliary fuel pump in the WVO supply line. Install the heat exchanger in the engine compartment. Install two tank valves, fuel lines, 10 micron filter for heated WVO. Make sure you have switch valves installed so WVO returns to WVO tank and diesel fuel returns to diesel Fuel tank. I know this is a vague set of instructions for installation, but if you don’t “get it” don’t do it; you don’t have enough expertise and you could screw up a valuable diesel engine.
Switching to WVO
I always start on diesel and switch to WVO when the engine water temp is over 100 degree F. When the engine reaches temperature, I switch the fuel return valve from the diesel tank to the WVO tank. Then I switch the fuel supply valve from diesel to WVO. Now you are 100% on WVO.
I leave the system on WVO for running errands, and if the engine will not have enough time to get cold before the next start. You will not notice any difference starting on WVO or diesel, if the engine stays warm. When I shut the engine down for the night or an extended period of time, I first switch the fuel supply valve to diesel and let the engine run a couple of minutes to flush the primary filter, injector pump, and injectors of WVO. This will also run a small amount of return diesel fuel into your WVO tank. (I have more about that later.)
Road Tax
Pay attention to this! If you use purely WVO as a fuel, then you must pay road tax on it. However, there is no tax required on fuel additives! My WVO tank always has some diesel fuel in it, due to the shutdown flush process. There are no laws that I know of that regulates a limit on the percentage of allowable tax free additives in fuel, so all WVO I burn is an additive to the diesel fuel, even if it is 99% WVO additive. It also burns cleaner and reduces pollution from exhaust.
As an idea to pursue for the adventurous, you can add a jar of water with some electrodes in it that bubbles HHO gas [–a 2:1 mixture of oxyhydrogen–] into the air intake and increase your fuel mileage 15% or so. I’m just saying’. However, ya better know what you are doing, because HHO can make sudden loud, dangerous noises if you mess up.
My Experience and Cost
My WVO experience has been all good. It usually costs me less than $200 to set a diesel up to run on WVO, but I scrounge tanks, switch valves, and fuel filters. It pays to start with a new auxiliary fuel supply pump. Tear down an engine that’s been run on WVO for a while, and it is clean like new inside. The WVO burns clean and get rid of all the stuff diesel fuel leaves in your engine. WVO is stinky and messy to collect and process, but I am messy. It gives me great satisfaction to be able to use WVO, not to mention my costs are about a nickel a gallon, and it really doesn’t smell like french fries running down the road.
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