Long term engine wear on wood gas

Hey folks, new forum member. I just have some questions regarding the long term engine wear wood gas creates.
I see loads of videos of people running engines on youtube but no follow up video or how long or how well it ran.
I want to build a larger genset for my home. I live off grid on solar already but there is a lot of stuff you just cant do with solar and most specifically inverters. Larger induction motors like an air conditioner or power tools are bad for them. How does wood gas compare to quality ethanol free gas? Is charcoal cleaner than wood chunk? Whats the longest anyone has ran a single engine on wood gas?

Thank you for your time, actual information is hard to come by. Most of its blog spam when i google wood gas.


Hey Joshua, welcome to this forum. You came to the right place for good honest information without the “blog spam”. As far as I can remember, there are no engines that wore out because of the wood gas that ran through them. Tar on the other hand has ruined a few engines in the early days of experimentation and is still something to watch out for.



I haven’t run an engine on woodgas yet, but I don’t think anyone has had an engine fail from wear&tear relating to woodgas. A few have forgotten to account for a variable, made dirty gas, and tarred up an engine. A few engines failed for reasons that were probably not woodgas related, e.g. a thrown rod.

I think that several folks have put 30k miles (50k km) on their woodgas vehicles, but then had to replace the fire-tube, which is in sort of a Hellish environment for metals. I think that it’s mostly just a factor that few folks on woodgas are driving lots of mileage, being generally rural folks who aren’t driving a whole lot, as opposed to worrying about engine wear.

I think a few have run high hours on their generators, but again, I haven’t heard of any earlier-than-expected failures in that demographic.

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Welcome Joshua, A lot of variables involved here. My limited experience is with a 1995 Dakota 318 cid It now has 192000 miles on the engine, and I suspect it had relatively good care on gasoline before I bought it. I have put the last 37000 miles on it with wood gas in the last 3-1/2 years. I have not seen any damage other than an old motor getting older. It uses a quart of oil in 3000 miles which is not bad for it’s age and hours. I’m just enjoying it while it lasts.


Hi Joshua,
based on what l have read in some older researches woodgas is better for the engine thain petrol. Less abrasion but l think the valves have shorter lifespan.
a lot is up to the quality of gas. Hard particles and tar.
But l only drive on wood for 7 months now so i hope the pioners chim in.


Hello Joshua and welcome to the DOW

With several vehicles I may have driven over 300K the last 12 years . I haven’t experienced any more engine wear than one would expect on gasoline .

Over the years I have wore out several motors and had to walk for help a few times. They were gasoline and diesels .


Hello Joshua , I run small generators on a daily basis for about 4 hours to top up my batteries on winter days when there is little sunshine or if I need to use power tools ect , I am not off grid ,but i enjoy being able to supply my own power needs .
I run my engines on charcoal , and nearly all this charcoal comes from my wood burning fires in the house so its not like i am wasting heat to make charcoal ,i also have a large cone for when i need to make larger amounts for friends , if you want something simple to build and simple to run i would look at building one of Gary Gilmores simple fires to start , and as long as you have a decent filter as everyone else mentions there should be no harm done to your engines from the gas at all .
Largest gen set i run is 6kva right down to a 87cc 24 volt DC battery charger


oh boy this is the kind of information I have been looking for. We have long overcast winters here. I have an extra midnite classic 150 I would like to power via pma or alternator but I need something cheap to run. I have a 5000 watt champion generator but I can’t really mess with it since the whole family owns it, we all went in on it. Great generator for the price but a bit of a gas hog for what we use. So i take it charcoal is cleaner and has better run times?
I see a lot of talk about imbert and fema types. Imbert from what i read is cleaner but a lot more complicated and expensive but a fema is less picky on fuel and lasts longer because of the colder burn temps. Is this correct?
Just looking for something thats long term and relatively cheap. I know thats a case of pick one but i want to try. Especially long term. I’m a bit worried about the future.

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FEMA gasifiers are tar makers. They were designed for a quick way to get an engine moving in a situation where one doesn’t care if it’s a “one-way trip” (engines run fine on tarry gas, but once they cool, the tar hardens and seizes the engine: game over.)

In theory, with very consistent fuel and load, one could build and design/run a FEMA without making tar for long-term but that’s only a few very rare cases.


So with say charcoal, which is very low in moisture, filtering and very cool gas (from what I read thats supposed to force the tar out?) a fema could work?
The filtering doesn’t look like it would be super hard. Cooling could be done. I would imagine a good radiator block or something with a crap load of fins would do a good job. Maybe a 12 volt blower to cool it down quick.

Charcoal is the way to go if you want to be a 100% sure you will not mess up the engine. With good charcoal it is inpossible to do any harm to it no mather what you do (exept if you let it suck dust in). You allso need allmost no cooling and the filter can just be an old sock. But you have to make charcoal.
There are people on the site that made very good simple and cheap charcoal gasifiers. Look fok Koen Van Lookens designs, Garry Gillmores simple fire, Don Manns geo tracker and my Seat Arosa 1.0.


Hello Joshua,

When we are talking Imbert or FEMA we are talking wood gasifiers. Charcoal is is a different setup. A bit simpler. Then you don’t have to worry about tar at all (if the coals are well cooked).

I don’t belive tar can be filterd. If you run a wood gasifier the gas has to be tar free when it leaves the gasifier. Filtering is just to remove soot from the gas.

EDIT: Ops, Kristijan! Typing at the same time :smile:


So does the temperature of the gas affect how much tar is in it? Will cooling it to room temperature or close help?

Also on a side note the mechanics of this forum, the way its posted and set up is amazing.

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If the temp in the glowing heart of a wood gasifier is high enough tar will burn and not slip through. Cooling is just to condence moisture out of the gas and make it more denst.


Hi Joshua.

About 4 months ago, I had a goal similar to yours, and was entirely new to charcoal gasification.

I built a simple fire charcoal gasifier and had a generator running pretty quick (you can build a simple fire in a weekend).

Since we are at similar stages of learning, you might find it interesting to look at my thread.

There are people here with decades of experience and knowledge on this subject. You have definitely come to the right place.

I will give you my thoughts on your project to help get you “jump started.”

  1. I would strongly consider a charcoal gasifier, such as the simple fire, for your first gasifier. These work well in a “generator” setting, and they are significantly easier to build than a wood gasifier, and you are very unlikely to damage your engine with them.

  2. I don’t know how big of a generator you want to build. I just built another one, which you can see near the bottom of my thread. If 7200 watt continuous, 10,000 watt peak sounds sufficient for your needs, then you might want to try something like that. I am very pleased with it. The only change I would make is to go with the larger v-twin 22 hp predator engine, if you want to make full rated power from charcoal gas. You could build such a generator (gasifier and all) for around $1,300.

However, you don’t have to “tear up” your existing generator to try it on charcoal gas. It is pretty easy to adapt it to charcoal gas, then go back to gasoline. You can build a simple fire for probably $200 if you scrounge up some parts, and try it. It is very unlikely to damage your generator in any way.

3 The only problem I have not solved yet is the life of the “nozzle” for the gasifier. You will be reading about that. There is a seperate thread which discusses nozzles for charcoal gasifiers. If you want a quick solution and want to stick with the simple fire design, look at Dave’s nozzle. He basically casts refractory cement around the nozzle. He reports a life of over 100 hours on those nozzles. Which is not bad. If you want to consider significantly changing the design, then I would think about a “hearth” style nozzle, which admits intake air from the bottom. That is probably what I will try when I build my next gasifier.

Good luck with your project!

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Well long term is the end goal. Honestly since wood is “free” if i want it to be or VERY cheap (under a dollar a gallon equivalent) I’m not super concerned about the fuel efficiency. Was thinking of a ford 300 inline v6. 1200 rpm and lowered compression. I’m pretty sure when its all said and done it might be 25-30 hp. I would probably run a alternator/harbor freight engine combo to start though. I am pretty sure my family does not want me touching that generator. The engine might cost over 1000 on its own. If i hit my favorite junkyard supplier I could find a low mileage engine of a different model for as low as 200-300 bucks. I have a generator head but its 3600 rpm. Lowest i can find online is 1800. My grandpa is a pretty smart guy, he figured out how to build a regulator (which pretty much works on just about any shaft driven power source including hydro) so i think I can make it keep a decent 60 hz. The only thing I would be missing is AVR. Not sure if it would be possible to add my own. I could skip the whole generator and use a PMA with my charge controller and just use it to rapid charge my batteries.

So the nozzles are the weak point? 100 hours is…pretty low. I’d be putting 10-25 hours a week on it.
Would higher grade metal work? Like a high temp grade of stainless steel? I have a local metal supplier that can get just about anything.

Generally, with the simple fire, you build the nozzle port so that you can just screw it out and screw another one in. Also, I understated Dave’s results. I think he actually reports 150+ hours. So, you would just be changing nozzles every 2-4 months. No problem. Just treat it as a consumable. It is not an expensive part.

People have experimented with many different metals and many different nozzle designs. I don’t think stainless helps you much. I tried one, and it lasted about the same as the black pipe. But your mileage may vary. We are waiting to hear results on a titanium nozzle. I was tempted to have a tungsten nozzle milled, until I found out it would cost $800 (yikes).

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Here is the nozzle thread.

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I have a metal nozzle in my charcoal gasifier with about 6000 km on it so that is wery doable. I think Koen has some great resalts sllso.


Welcome Josh, To get to all the tech stuff you really need to consider becoming a premium member, well worth it. I don’t know how much of the charcoal is on the premium side of the site. If your plans are to run auto type engines Wayne’s design is the way to go.