Oil gasifier idea

I’ve been trying to figure out a method to make a waste oil “gasifier” so to speak. I know it’s been talked about here before, but I have a few ideas I wouldn’t mind running by you guys to see what you think.

This guy seemed to have success. By success I mean the engine actually ran, admittedly poorly ran, but it ran nonetheless. I’m sure the first wood gasifier powered engine didn’t run great on the first try either, but if it will fire even a couple times then it’s safe to say it can be made better.

Obviously this guys setup is incredibly inefficient, and some improvements can be made. Here are some drawings of what I’m thinking of…

So my idea would be to have the exhaust, after passing through a catalytic converter, heat oil in a heat exchanger. The heat exchanger would most likely be a coiled up copper or stainless steel tube, although if a guy could get his hands on an old EGR that would most likely work just as well if not better.

The oil would be pumped through at a consistent rate, the pumping rate fiddled with and tuned for the best heat exchange rate. Once passing through the heat exchanger it would go up to the “carburetor”. In the carburetor there would be an inlet and return line, so that the “bowl” will not fill up 100%, instead leaving space above the oil level for the hot smoke (vapor) to separate out. A needle valve of sorts would be installed in order to tune the air/fuel ratio for the best results.

The hot oil can then return to the pump, not the tank, where it can be recirculated through to be heated (vaporized, gasifier) once again. An orifice plate can be installed on the outlet from the oil tank so that the system can replenish itself of whatever oil is being used up to fuel the engine. My thinking behind using the orifice is that you will achieve more “gasification” by reheating as much as the hot oil coming back from the carburetor as possible, rather than having to heat the colder oil from the tank every single time. It probably wouldn’t be a bad idea either to have a liquid to liquid heat exchanger installed to use engine coolant to preheat the oil before it passes through the exhaust heat exchanger. The engine coolant is waste heat anyway, so why not put it to good use first.

Obviously there are a few drawbacks to the system. From a cold start with no exhaust flow the system couldn’t build the heat needed to gasify the oil. I think there are a few possible solutions to this. Number one is have a “dual fuel” sytem, where you can start on gasoline and once everything is up to temperature switch over to oil. The other could be to TEE in a sort of oil burner near the heat exchanger which could be used to heat and gasify the oil that way until the engine is producing enough heat on its own and the oil burner system can be shut down.

I’m not sure if this idea has any merit or practical feasibility whatsoever, but I do like the idea of using waste heat from the engine to achieve the gasification. Catalytic converters get extremely hot, the “smoke point” of most oils, which is the temperature at which they will combust, is usually somewhere between 400f to 500f. This temperature is usually far exceeded at the outlet of a catalytic converter. My thinking is also that it should be almost self regulating as it were, meaning that at low engine load, your exhaust temp goes down, which in turn will gasify less oil, but hopefully still enough to maintain what is needed for the engine. At high engine load, the exhaust temperature goes up, which in turn will gasify more oil, again hopefully enough for what is needed by the engine.

We know from the video posted that it is in fact possibly to run an engine on oil smoke, maybe with some good tweaking and effort it can be made to be practical.

Anyway that’s my idea. Please let me know your thoughts, or maybe problems that I have failed to think about. :slight_smile:


Oil uses a lot longer carbon chains then gasoline or even diesel, basically industrially they ‘crack’ it to make the chains shorter and use a ceramic catalyst.

You will have much better luck doing an oil drip in a charcoal gasifier which will crack the oil. The shorter the chain, the lower temperature of vaporization, and easier ignition. There is some crossover in chain lengths between gas, diesel and oil. but essentially If you want to go that route, you probably have more success using timings and compression tuned for diesel.


Hi Sean. Yes I’ve read about Gary gilmore using the oil drip on his systems with great success! Apparently brings the system very close power wise to a straight gasoline system.

I am aware of people using waste oil to power a diesel, it’s a very interesting system. However my goal is to see if this could be used to run a conventional gasoline engine, since they are far more common, both in vehicles personal stationary equipment such as small generators, wood splitters, etc.

My main purpose is to see if this could be used as a standalone system without the use of an charcoal or wood system. I do understand that the oils will crack a lot easier doing it that way, but it would be interesting to see if it could stand on its own two feet so to speak. As I pointed out the video above proves that oil smoke can in fact run a gasoline engine, but is it possible to make anything better than what he accomplished or will it simply be a waste of time.

Obviously the goal would be to try and make a system that can do this using nothing but the waste engine heat from the cooling system and exhaust, but perhaps that’s just a pipe dream.

If it turns out that the waste heat from the engine simply isn’t enough to accomplish this, I did have another idea of making a small waste oil burner that would provide the heat to bring the oil to its smoke point. I know it seems like a waste since much more oil would be used in that system, but waste oil is either free or very cheap anyways, so in a sense who cares if you need to use a little more of it. It’s way better than paying almost $2.00 per liter for gasoline (Canadian dollars).


Personally I would rather use the waste oil in a heater or furnace to heat up water. I don’t think running the oil through the exhaust is a terribly good idea, lots of thermal stresses and risks of cracks in the system. Big chance of fire right under your vehicle and spilling onto the road.


Gary wasn’t the first that did oil drip, there have been several and some even with wood gas.

Here this article will be helpful to you and get you going down some rabbit holes:

If you poke around, you can find a tuned zeolyte catalyst for sale. It has a specific name, which I don’t recall off the top of my head. It ends in like -75 or something like that.

I believe sulfur gums up the catalyst as well.


Hey Cody, yeah that route might not be the best idea, but if needed I supposed a separate oil system with a superset heat exchanger could be used that isn’t a part of the exhaust?

Are you talking about using the oil system to heat water and then use that water in a heat exchanger? Or just in a general building heating application? I actually have a waste oil heater in my shop and it works very well, but in this instance I’m looking to see if there’s some feasibility to using it as Otto cycle engine fuel source.

Just in a general home use. Hot water heater for either a boiler, or just to have hot water for the house or a mixture of both.

A lot of garages save the oil just for that purpose, to burn it in the winter and heat the garage that otherwise would be too expensive to keep warm due to poor insulation.

Also forgot to add, I’ve used waste oil in my charcoal gasifier and I didn’t like the flames that would come out of the nozzle intake at idle and shutdown. Even with a flame arrestor it would slip past and ignite. I didn’t see much power gains and felt like water drip to me and the suspicion it wasn’t cooling my reaction down by much either.

Used oil also has a lot of grit and carbon in it, you’d have to process it to not damage any pumps to keep the oil moving. I want to say Bruce Dualfuel has a topic on it, I’ll find it and link here.(EDIT: It’s on the premium side, sorry about that). He processes it to use in a diesel engine.

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You have to crack it to gas. You can use it to melt steel though depending on what you want to do in your shop.

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These are Hot bulb or semi diesel engines.
They work by inject at low presure a stream of fuel into a hot precombustion chamber where the fuel vapourises…
On compression enough air is introduced into the precup for the mixture to ignite.

They can burn any oil or fuel as long as its relatively dirty free and flows…

Not really much of an advantage to any other method of using heavy oils or waste oils to run engines when compared to this simple direct injection method.
AS a side note these will happily co-fire woodgas at ratios diesel engines can not tolerate


Thanks Wallace! Yes I love these engines, I’ve read that they could run on just about anything. I’ve also heard these referee to as semi diesels.

Unfortunately these engines are hard to find, especially in my area. They also have an extremely low power to weight ratio, hence why they were so enormous for their power output.

But I think these also prove the point that if you get oil hot enough it will run an engine. Now the question remains whether you could make a spark ignition engine run on the vaporized oil/smoke.


Spark igniting oil or vegetable oil has challenges.

I actually heated with waste oils for a while. I converted siphon nozzle torpedo heaters to burn used vegetable cooking oil - something that has health issues. I built a babington burner to heat my home an entire winter. Then I designed a very successful waste motor oil burner that only needed low voltage to operate a metering pump.
It was my experience that the using heat to vaporize the oil distills the light fractions to vapor and this is what makes vapor carbureting systems appear to function for a short time. However - eventually the heavy fractions build up in the vaporizer over time. Typically the heavy fractions becoming carbon that needs to be cleaned out of the vaporizer.
Using spark plugs for ignition has issues as the carbon that invariably collects on the cool surfaces conducts electricity - shorting out spark plugs and in the case of continual burn systems - the ignition transformers burn out when the spark plugs short. No matter how hot a style spark plug that I used or created - I simply could not get them to operate hot enough to burn off deposits.
I burned out a number of ignition transformers before proving to myself that burning oil in a low pressure environment was all about achieving a high temperature environment. I ended up using silicon carbide hot surface igniters from clothes dryers for the torpedo heaters with good result. Down side is that they are fragile.
Running engines that consumed oil had similar challenges. Oil collects on the inside surfaces of the engine - slowly migrating to the spark plug where it vaporizes off the insulator - resulting in carbon that shorts out the plug. Non-fouling caps could be fitted to the spark plugs to attempt to shield the plug from the oil and allow the plug to operate in a pre-combustion chamber. Ignition timing should to be advanced to compensate for the delay in flame propagation. I changed from D-16 to D-23 heat range spark plugs. I even found some hotter plugs - D-27(?) at an antique car swap meet. Better but those were still not hot enough. I modified the non-fouling caps to accept the more open style autolite 46 spark plugs used in my Ford 200cid engine. I would then buy the hottest version of those spark plugs that I could get.