This is probably the main reason you came to this site. You have a diesel vehicle and you want to make your own fuel. Great! You are at the right place. Hopefully, I can answer most of your questions and get you on your way. There are a few factors you need to consider to determine if black diesel is right for you.
- WMO: Waste Motor Oil
- Black Diesel: WMO
- W85 (or other): A blend of waste oils containing 85% waste oil and 15% RUG
- RUG: Regular Unleaded Gasoline
- D2: No.2 pump diesel
- Micron: 1×10^-6 or 0.000001 meters- used as a filtration standard
I just wanted to point out that the older IDI (in-direct injection-mechanical injection) model diesel engines lend themselves a little better to waste oil burning. That is not to say that it cannot be done in a newer engine. When ran in an older engine, W85 can be ran up to 100% (in replacement of diesel) where newer vehicles may have to be run in a much less concentrated amount. I have heard of some running it in their 2012 Cummins at a maximum of 50%.
Some of the engines that I know of that are IDI are:
- Ford 6.9L
- Ford 7.3L (up to mid 1994)
- Mercedes 240D, 220D, 190D
- Mercedes 300D, SD, & SDL (OM617, OM602, OM603)
- Some Kubota older diesels found in Ford vehicles (Ranger and Fiesta)
- 1980-1990’s VW diesels
- Chevy/GM 6.5L and 6.2L
Oil Selection and Availability:
Having the ability to burn waste oil really doesn’t mean much without a supply of oil to burn. To make this project feasible or worthwhile, it really is important to have a solid supply and storage facility. This was also a determining factor for me. In my area, there are multiple places to get waste oil. I live in a relatively rural town. This is a major benefit due to all the ag machinery and mom & pop oil change shops in addition to my job site of wind turbines. On the contrary, there are only a couple fast food joints in town, so veggie oil isn’t all to common.
I guess I need to interject and explain what types of waste oils are relevant to this application. Essentially, any oils not containing water which are low enough in viscosity to flow through your lift pump and fuel filter without cavitating your injection pump while not adding more than 20% RUG. One other consideration is that waste motor oils and veggie oils are not compatible for some reason. They tend to congeal when mixed and can cause major issues in the fuel system if ran simultaneously.
Some examples of good oils:
- Petroleum based hydraulic oils
- Engine lubrication oils
- Automatic Transmission Fluid (ATF)
- Transformer oil/Mineral oil (PCB free)
- 2-stroke oil
- Cutting oil
Some examples of bad oils:
- Water based hydraulic fluids
- Oils containing emulsified water
- Gear oils
There are a few other items that need to be addressed. Generally speaking, this is not something that should be done in a 5 gallon bucket (more on that later). Processing waste oils into a useable fuel takes space. Earlier I mentioned that you need to have good storage facility. What that means is that you need to have enough space and capability to store the fuel that you need both before and after you process it. In my case, I have two 330 gallon IBC totes to store unprocessed oil in and a transfer tank in the bed of my truck to hold processed fuel. Next you will need to make room for your processor or filtration unit. Mine is pretty small and probably uses an area 7ft(L) x 7ft(H) x 3ft(W).
Spills are bound to happen, hoses burst, pipes break, and life gets in the way and someone forgets to close a valve. you need to consider a containment area. Pouring oil on the ground is no longer acceptable. If found during a house inspection, your house may become unsellable, not to mention any environmental violations or homeowner insurance violations you may be in conflict with. Long story short, it can really hurt you if you hurt the environment these days! Be careful and contain your project (Pig Mat is a good friend) .
It may be a good idea to check into your local laws and regulations regarding alternative fuels. It would really suck to get a ticket for burning this stuff because an officer felt you were in violation of some law when he dips your tank full of waste ATF.
Before you proceed any further, please take note that I am in no way, shape or form taking responsibility for anything you do with the following information. I will not be held responsible for ruining your engine, any fines you may incur, tickets you may get, or any other scenario that may come from using information posted on this website.
That being said, you can rest easy that if everything is done correctly and with the right precautions, WMO is a tried and true safe fuel.
So you have a good source of oil, room for oil storage, and a containment plan, maybe you even looked into some laws and regulations. Lets get started!
I did a lot of research on this topic and I will preface this with a note that there are many different ways to do this. I can honestly say that there may not be a single processor out there that is exactly the same. However, what is the same about all good processors is that they keep in mind that the most important thing is immaculate filtration. Filtration can be done in a number of ways:
- Hydraulic/oil/fuel canister/cartridge filters
- Whole house water filters
- Bag filters
- Plastic mesh filters
In addition to the above, you can also vacuum filter or pressure filter your oil.
- Vacuum filtration: This style of filtration “sucks” the oil through your filters and into your barrel.
- Pressure filtration: This style is where you “push” the oil through your filters and into your barrel.
There is some controversy over which method works better, however I would have to say that the pressure method is by far more popular. Each method has its own advantage. vacuum filtration will not allow you to bypass your filter and will cut flow off once a filter plugs. This method is slower than pressure filtration. Pressure filtration, although faster, has the ability to build much higher pressures. If you are not careful, filters can over-pressurize and explode or bypass the filter completely (impossible to tell without a pressure gauge and an initial reading).
When using filters, I like the canister style filters the best. I think they provide adequate filtration while being affordable and easy to service. They are easy to get and come in all sorts of sizes, efficiencies and micron ratings. I also prefer to use the vacuum filtration method since I feel more comfortable with lower pressures.
The other style of filters work at a range from ok to great. I do not have personal experience with the bag or whole house filters. I chose not to use these styles for a couple of reasons. Initially, they seemed cheap and mis-purposed for WMO filtration. Whole house filters will filter down to 1 or 2 microns, but are intended for water. I am not certain how they would hold up to the corrosive elements of WMO, nor am I certain of their efficiencies. For what they are, I can just as easily get a caterpillar 2 micron absolute fuel filter for a similar price. As for the bag filters, they would suit WMO just fine, but not my application.
I personally use bucket screen filters. However, this is just a very large micron rating so that my more expensive filters do not get plugged. I would not trust them at a smaller micron level than maybe 75 microns.
Last but not least, the filter of all filters: the centrifuge. There are two main types of centrifuges:
- Direct motor driven (open bowl)
- Pressure driven
A centrifuge is a way of force settling heavier materials out of a liquid. For oil, this can mean sediment, sludge, water, and carbon. They are said to be able to have filtration powers down to 0.5 micron and many consider this the only needed step.
Both styles are great and work great, but in my opinion, the direct motor driven style is probably better. Do not discount the pressure driven centrifuge, it has it’s perks as well. From my research, it seems that the open bowl style centrifuge requires a much simpler system. If you have adequate headroom, all that is needed is gravity to feed the centrifuge. While the feed rate can be relatively slow, I believe that some are able to clean their oil in just one pass. It also has the ability to remove free standing water in small quantities. The largest disadvantage to these is that they cost roughly $1200, almost double the cost of a pressure driven centrifuge. There are guys who have made their own, but just beware that a piece of metal rotating at 3450+ RPMs becomes a grenade when it forms a crack or becomes off-balance.
I own a pressure driven centrifuge and I will admit that my setup was much more complex than the open bowl style. Pressure driven centrifuges need a pump to feed the centrifuge. As the pressure builds, jets push the rotor faster and faster until it reaches 80-90 psi. I believe it would take roughly seven to eleven passes to get a solid 99% of the oil through the centrifuge once without any bypass. It is also important to not run any free water through your centrifuge since it will become emulsified.
One last point about centrifuges that I want to make is that they do what other filters cannot. If you run 5 gallons of waste engine oil through three filters, down to 2 micron absolute, you would think everything would be “clean”, right? Well, not really. there are some things that just can’t be filtered. Sludge and carbon from blow-by are some examples. Centrifuges exploit the laws of gravity to filter those things out and it is the only way beyond months of settling your oil to deal with it.
Heating and Blending:
Heating is a great way to speed up the filtration process and evaporate any emulsified or free standing water in your oil. When and how you determine to heat your oil will be up to your preferences. If I could do it over again, I would have two heaters in different stages of my filtration rig. I should mention that heating is not necessary, but is a means to making WMO processing much easier, especially in colder months. Some heat prior to their centrifuge, some heat after, and some do both.
I will recommend blending with RUG no matter what. I prefer it year round. My recommendation is that RUG be blended into your fuel AFTER you heat and cool your oil. I think we all know what happens when you leave a gas can in the sun. Also, if your RUG is evaporating ($$$ loss), your blend characteristics will change. Finally, when it comes to blending, i think it is always a wise choice to add in a cetane booster with injector cleaner. Side effects of WMO is something I will have to post on later.
For more information on using WMO and black diesel, please go to my Dropbox page. WMO Dropbox
My Filtration Setup:
Now that we have covered all of the topics that I can think of, I wanted to share my setup with you. Like I mentioned earlier, I don’t think there are two alike. While I believe I have a good example of a processor, feel free to copy, expand, or create your own. We can only benefit from moving forward and trying new things.
I Used plastic 55 gallon drums for my processor, mostly because they were free and available. They are also the easiest to modify and work with. The first drum is where the process begins. It goes through a 75 micron bucket filter and fills the drum to my desired volume.
Once I fill that barrel to the desired height, I open my valves and turn on the pump to suck oil into my polishing tank. The first filter is the 23 micron (nominal) hydraulic filter, followed by the 10 micron (nominal) Goldenrod water separator, and then the 2 micron (nominal, high efficiency) fuel filter.
After the 2 micron filter, the oil will get pumped trough the centrifuge bypass pipe into the finishing barrel. Once all of the oil has passed into the finishing barrel, I can close the valves from the filter side and open the valves to the centrifuge. At this point, I will heat the oil and circulate it for 24-48 hours, depending on how dirty it is.
My heater is a stainless steel submersible 120VAC heater. I bought it on EBay for about $18. It doesn’t have any info on it, but it works well. Someday I hope to het it hooked up to a thermostat so I can regulate oil temps better.
At this point, the oil has been filtered, centrifuged and maybe even settled. It should be relatively “polished” or clean enough for use as a fuel. The next step is to blend your oil to make it useable as a fuel. If the oil is too thick, your in-line fuel pump and injection pumps will not be able to keep up with the fuel demand. This may cause surges in the engine and can be damaging to the pumps. Likewise, fuel that is made or cut too thin may also ruin the pumps due to lack of lubrication.
If you weren’t aware, injection pumps (particularly the Stanadyne DB2 found in Ford and Chevy IDI’s) are very particular pumps that require fine fuels and good lubrication due to their small tolerances. This is yet another reason why filtering is so important.
To blend your fuel means to add other products. In this particular scenario, the usual products are Regular Unleaded Gasoline (RUG) and injector cleaner. RUG is a natural solvent in oil and will break the intermolecular bonds in oils and will thin the oil and reduce its viscosity. I add RUG at the rate of 10-15% of total volume. Some feel comfortable using up to 20% RUG, but I feel that may be a little too much unless you have thick oil or it is really cold out. I also use Power Service Diesel Kleen injector cleaner (silver bottle) to blend because it has cleaning properties as well as cetane boost (any can be used). The rate at which I add injector cleaner is 0.66 oz/gal (total product). This is listed on the back of the bottle as the recommended dose for cleaning your engine, essentially a double dose.
The math behind figuring out how much RUG to add is relatively simple:
The total gallons of RUG to add to your oil is equal to the total gallons of oil divided by your RUG percent minus 100. So, 15% RUG-100 is 0.85. This is also how the term W85 was created (85% oil). Then subtract your total oil and you will be left with the amount of rug you will need to add to your oil.
Next, we will look at the Diesel Kleen equation:
Now that we have figured out the proportions, they can be added to the finishing barrel to be mixed with the oil. At this point, I like to blend or mix the fuel for another 24 hours. After it has been thoroughly mixed, it is ready to pump into your vehicle for fuel!