SOHC'S V hearth gasafire

Hello, I am new here, I started this project a wile ago when fuel prices went super high, I live out in the wastelands in the bush so wood is not a problem, I have skills that are now useless such as blacksmithing, repair of vintage vehicles and welding skills that are not used today anymore, I thought I would give building a wood gas car a go, I still need to find another suitable vehicle witch has a distributor and has a engine of 2500cc or bigger.

I made this video instead of taking lots of photos


Wow that is going to be some heavy beastie of a machine when you get done , and it looks like your well on the way to getting it sorted , you seem to have all the skills needed to complete the job and i am sure the wood gassers here will certainly help with pointers to getting it done , so welcome aboard mate .



Welcome! If you can’t find a donor car, it might be a candidate for a stationary generator. It isn’t like electric is cheap there either.


Its going to be very heavy just like the old WW2 ones, I got some sizing charts from a Swedish guy and this apparently can be adjusted like a tailored suet, I am going to add a hot filter now after he sed they improve fuel consumption a lot,

I made the cooler way too small, going to do a triple row filter from something like copper tube and make the enormous gas scrubbers under it,

We have a fast growing hardwood that has no bark on it and it is long and thin, I think this would work well and be easy to process


All l can say is wow. You know what you are doing. Keep it up.

Just one correction. Actualy you do not want a high reving engine. Woodgas is a slow burning fuel and at higher revs the flame speed, system drag etc take a great cost on efficiancy. Allso higher rpm runing engine needs a gasifier with greater turndown ratio in order to perform well and be able to idle.
I did gasify a 2006 1.6l Chevrolet Lacetti and l run in exactly those problems.

Allso, the gasifier seems big for a 2.5l engine? Whats the restriction dia?


Welcome to DOW. You certainly do seem to have all needed skills to finish the project, and have about 2/3 of the fab work accomplished.
You’ve certainly come to the right place for final design and assembly info to make a working system.

You state in the video you have a Volvo with an automatic transmission, but think you need a manual for best results. If you look at the examples of builds here, most are automatics. And the best performing conversions are low rpm, bigger displacement, over powered engines for their application, though Mr Olsson in Sweden may want to comment, as he’s run 2 quite successful systems of smaller displacement, higher rpm.

A gas (petrol) powered tractor shouldn’t be discounted as a candidate.

You mention discussion with a fellow in Sweden - what design parameters are you working from? I assume Imbert dimensions, and calculated on what flow / displacement engine, at what rpm? What are you considering for hopper design? Members here like cross sectional sketches, and pics.

Hopefully you have an engine based design calculation, and @gasman can help check fundamentals. Although, the essential calculations are clearly laid out on the site under DIY.

Btw, cones can be fabricated easily from flat sheet steel. A pattern can be derived by making 2 half circles representing the large and small diameter in light plywood, joined by a piece representing the height. When rolled on a flat surface they will describe 1/2 the pattern.

The grate you show might be improved on. Experienced members can guide you regarding spacing and shaking. The shaking is usually a rotating or sliding action, and often proves unimportant on a vehicle mounted system. Spacing is important to slip the right size of char. The optimal heat resistant grate design is inverted light angles to allow ash protection from above, and heat radiation to below, and solidly attached alternately on one side only to avoid warping, though many grates here are just stainless plate torched through, hung on chains for movement.


Garry, not to put words in JOs mouth but the vehicles he drove and still drive are rather slow turning. I think l remember he mentioned the Rabbit run at 2200rpm at 100kmh. Mazda somewhat similar?

I too found my Mercedes (2100rpm at 100kmh) likes woodgas much more thain the moskito engines l previously gasifyed. It just runs nicer and has more torq even thugh weight/power ratio isnt wery different.


Yes, let’s see what Jo says. My experience with smaller trucks (Mazdas) is that they are running over 3,000rpm at 100km. I would assume the Rabbit was similar given the small displacement. The Mazda may be lower rpm, as it’s a larger displacement engine.


Hi again Rudi i forgot to mention , have you been following the adventures of a fellow Kiwi on YouTube
Just in case you had not seen him .he builds some great automated add ons

All the best


Welcome Rudi,
I agree with Garry and Kristijan. Big, slow turning engines with high torque at low rpm are probably the best woodgas candidates. However, they are hard find. Only a small minority of people, in a remote area of the world called USA, have plenty :wink:

That would have been my guess too, but for some reason quite the opposite actually.

My 1.8l VW Rabbit pickup ran only [email protected]/h. That motor liked to rev on gasoline but combined with the little 8" gasifier, best torque was around 2200rpm. A good match, since most open roads here have 90km/h speed limits.
The 2.6l Mazda pickup is actually geared higher. Something like [email protected]/h. It pulls best around 2500rpm on woodgas.


Good morning Rudi and welcome to the DOW.

Looks like you are well on your way and a good looking job.

For wood gas vehicles I like the auto trans. The first truck I gasified was a manual but all after have been auto.


Hello thank you for the replys, I meant fast idol by keeping the RPM up to keep the system working not high RPM like an engine pulling 14,000 RPM, I am looking for a big old 6 cylinder

I dont like running an automatic at fast idol, it puts stress on things when you put it in drive at 1500 RPM.

As for the hearth ring it has a restriction for a 3.8 ltr engine at the moment, I have made a much thicker smaller one witch has not had the hole cut in it yet, it lifts the restriction up higher closer to the nozzles for around 2500cc


Smart. Very smart.
tree-farmer Steve Unruh


Welding skills not used any more?! sounds like your crazy… maybe but crazy cool! that’s an awesome rig you got going on!

1 Like

Hi rudi, welcom too dow, I was wondering what you thought you need hi RPM s too keep running. a good working gasifier can idle at normal 700 rpms and put a automatic trans in gear with no clunking from idle too motoring down the road.maybe i read your report wrong, wayne keith can drive his v10 dodge around his farm at near 500 rpms for over a half hour, before needs the gasifier warming back up a while by driveing truck back up too speed awile.keep up the good work, looks like you got the builders skills.


Hi Kevin, Rudi also has a Imbert style gasifier which does not have the turn down ratio we have in our WK gasifiers. But I sure he could use a automatic transmission like you say.


Don’t a lot of the guys, even ones with the WK design, have a knob under the dash with a string/cable to the accelerator pedal, so they can turn the knob and wind up the cable to pull the accelerator pedal for increased idle RPM’s? TomC


I use mine just to keep the RPM up to about 650 to 700 RPM for idling. My WK gasifier will idle for a long time. Lots of stored heat in the unit for turn down ratio. Some of the Imbert designs had to keep the RPMS up much higher to keep the temperature up for reactor to work properly. Preheating the in coming cold air is a big improvement for idling purposes.


What Bob said .

I open my throttle just enough for the motor to idle the same speed as gasoline . ( Maybe just a little faster .)


Haven’t done much but have been planning, and collecting more stuff, a friend of facebook is using a late model Chevrolet V6 engine in a pick up on wood gas with good results, it was fuel injected before,

I am going to build a new cooler / condenser using this heat exchange tube, I will use a big dia like 35mm ID so I can get a brush down them for cleaning and about 2 rows of 8 tubes or more.

Need to get something done,