SVO Conversion Instructions

Follows is a brief description of what is necessary and what is involved in a typical SVO conversion. These are not listed in any particular order.

1)  3-way valve(s) to switch between diesel and waste veggie oil (wvo) such as You may be able to find a suitable valve on e-bay or even pacific marine exchange. The way I typically install these valves is to have the valve stem come up through the floor boards in a location that can be accessed while driving. Ideally you want 1/4" will work fine for use with 5/16" ID fuel line. IF you plan to route your fuel return back to each fuel tank, you will need 2 of these. Otherwise just 1. The downside of not routing back is that you have longer purge times to flush all of the wvo out of your system for shutdown/startup on 100% diesel. The other option is to use electronically actuated solenoid valves, such as The benefit being that you do not need to manually actuate the valve and therefore the switching between fuels can be done automatically (once up to temp) and you can locate these valves where most convenient (rather than where you can reach while driving). The downside is the additional wiring and complexity this adds. I am a huge Keep it simple (KISS) fan and myself prefer the good old manual valve if it is easy to locate them somewhere where you can actuate them while driving. Note: if you already have a 2nd tank with working switching solenoid valves for switching then you don't need this.

2) WVO/coolant heat exchanger. I recommend buying a used oil cooler (i.e. from pacific marine exchange) and plumb it into your engine coolant and route your wvo through it prior to your ignition pump. I was lucky enough to have an unused ATF cooler in the bottom of my radiator that I simply routed my fuel through. I do caution slightly with the use of yellow metals (copper, brass, bronze, etc.) and wvo. I have been using both copper and bronze for over 1 year without any problems and have heard of others who have used yellow metals for years with never a concern, but under certain circumstances the wvo can polymerize when in contact with yellow metals and air. I suspect it may only be an issue with "bad" oil, or oil that has excessive salt in it. However, if you are concerned, you may want to with a stainless steel plate heat exchanger, something like the nickel brazed here or aluminum.

3) For cold climates I recommend an electric, 12 volt fuel heater to help get your wvo up to temp quicker to allow you to switch from diesel to wvo sooner. I have seen "knock-offs" on e-bay for cheaper. If you are handy with electronics, I suspect you could make your own. These heaters also allow you to start your vehicle on svo if used in combination with 120 Volt pre-heaters (see item #11).

4) Fuel filtering and dewatering unit. I suggest you pick up a used fuel filter/dewatering unit from pacific marine exchange and plan to use this solely for your wvo fuel stream. Depending on how well you filter your oil, you will need to change your filter elements every 3 months or so. I use the FCS1136 units and they usually have them for under $10 at pacific marine exchange. You can buy replacement filter elements from any parts store, but are much cheaper online.

5) Inline fuel strainer. I also recommend installing a strainer prior to your filter to strain out big chunks and prolong the life of your filters. These strainers have SS screens that can be simply cleaned out. I bought mine from Hardware Sales and they typically call them sand filters. If you take care in your filtering you don't need one. Lately, I have simply been letting my oil settle and have not been doing any filtering (I don't recommend this) and I am still getting 3 months out of my filters with these strainers installed.

Background info: I utilizes what is referred to as tube-on-tube heating of my wvo fuel lines using engine coolant lines. The ideal application for heating oil is tube-in-tube, meaning the wvo fuel line (typically being aluminum) is located inside a larger diameter coolant line (typically copper). This works well if your desire is to heat you wvo as it travels from your tank to your injectors, but at an expense ($). However, my design utilizes a final heat exchanger and the 12 v inline heater to achieve the final temperature of the wvo (160-180 F). Therefore, I see no need to invest in tube-in-tube heating. I also do not need to invest in more expensive, high conductivity tubing unless specifically necessary (I.e. to hold shape around fuel filter).

6) Fuel line. I used standard 5/16" fuel line available from Napa for my wvo fuel line. The wvo does not degrade fuel lines like biodiesel does and you will probably not have any issues with this fuel line. However, you would be safest to use biodiesel compatible fuel line. You can buy this online and I can sell you compatible, clear, braided hose for $2/foot if you like. You will also need hose fittings. Hardware sales has everything you will need. Aluminum tubing is also good to use and has the added benefit of being chemical resistant and having good conductivity. An I recently realized that 3/8" aluminum tubing is only $1.49 per foot at Hardware Sales, therefore since this is not much more than standard 5/16" fuel line and is also biodiesel compatible, aluminum is the way to go. You will still need sections of hose to navigate some of the tight turns, and aluminum tubing can be tricky to work with (it kinks easy).

7) Coolant line. For cold weather operation, you need to trace all of your wvo fuel line with coolant lines. I used some used, nylon airline, 3/8" and this has performed fine. It does get brittle with time. Regular coolant heater hose also works well (it is also a good idea to size larger than your fuel line, especially for long runs, so 1/2" heater hose is a good choice). Copper tubing can also be used, typically in combination with a flexible tubing. Copper has the advantage of being a good heat conductor. I personally use copper tubing to wrap around the fuel filter to keep it warm and assure that it does not get plugged with solidified oils at lower temperatures. Copper or aluminum coils are also effective to submerge in your wvo fuel tank to keep this oil warm enough to flow through your system. You will also need various fittings to accomplish the coolant routing (always need to loop back for circulation), including tees off of your heater coolant lines and ideally isolation valves incase you need to work on your system.

8) WVO fuel tank. Ideally, you vehicle will have an installed, 2nd fuel tank with all associated plumbing and switching and this saves you a lot of time and money. If not, you should install a 2nd tank. There are systems out there that rely on a single tank, however in colder weather you must run a mixture of diesel and wvo, plus if you ever have a problem with bad oil, water in your oil, plugged fuel filter, etc. it gives me huge peace of mind to always be able to switch back to diesel. Plus, even with the 12 v inline heaters, it will be a challenge on your glow plugs and battery to start your vehicle on straight veg oil or even a mixture in cold weather. Therefore, you need a 2nd tank. You can go as small as 5 gallons and as big as you want. The deluxe tanks are prefab aluminum with access port and heating coils bare bones is a 5 gallon bucket with sealing lid with ports plumbed in through the wall (I can provide you a bucket for free, I get them all the time). Something in between would be an aluminum tank ( modifed with an heating coil. My current tank is a 10 gallon fuel tank with a rectangular hole cut into it and a heater core stuck inside and sealed in place with silicone. Maybe one step up from a bucket, which I was planning on using but found this tank for free at pacific marine exchange. Whatever you use, you need to get a heating coil inside, whether that is just a length of copper or aluminum tubing or a heater core does not matter. An access port is nice to get in from time to time and clean out. Fuel gages are a nice to have. You never want to run out of wvo, you will suck in air and need to purge the air out of the fuel system. Baffles in your tank allow you to run the wvo out lower without sloshing and sucking of air. I do not have one. I just make sure I keep the tank near full and do not have a problem.

9) Both your diesel tank and wvo need to have a smaller primer pump of some sorts. You can buy the hand bulb type for cheap from pacific marine exchange, the type used on portable fuel tanks for boats.

10) For cold weather operation, anywhere wvo travels, it needs to be traced with coolant lines and insulated. Good insulation will also allow yourself more time to startup your vehicle on SVO when shutdown and not plugged in (see below). Typically, without insulation you can shut off your vehicle and let it sit 30 minutes and still start on svo. Much less in colder weather. Insulation will double this time. A cold engine will not start on svo. So if this happens, you need to switch to diesel and manually flush the wvo out of your fuel system. Remove the fuel line entering your injector pump, place in a small container, and pump the primer pump (see #9) on your diesel tank until you flush all wvo out. Then hook back up to your injector pump, pump a few more times, and start. There will still be some wvo in the injectors that will need to be flushed so it will not start easy.

11) If you want to start your vehicle on straight veggie oil (svo) in cold weather, you need to include 120 V heaters and plug in your vehicle prior to starting (typically on a timer). This includes a standard block heater, a tank heater and heat tracing for the wvo fuel lines. Basically same as above, anywhere that the wvo travels you will need secondary heating in addition to the coolant heating. Remember, cold wvo will solidify.

Please e-mail me if you have any questions or comments: