Help to choose engine

Hello everybody,

I’m new in this forum, and took the decision to take part in it because I’m kind of lost right now.
My name is David and I’m involved in a project of a technology transfer centre of the Technical University of Catalonia (Barcelona).
We want to build a pure mechanical gasifier capable to supply enough energy in a small hospital in a isolated zone of Africa.
The first part of our project is to choose a genset about 10-20 kW which runs with woodgas…
I have realized is almost imposible to get a genset capable to work with this gas… So our target now is to find a genset that works with natural gas, gasoline, or diesel and later we could modify the engine in order to make it work with syngas.
I have heard that diesel engines are the best to be modified…Other say that the best is to adapt NG engine…etc

Can you help me on this? I now that your experience on this toppic will probably help me more than a lot of literature…

Thanks in advance,

Kind regards,


Hi David
Welcome to DOW.
I have a WK gasifier powering my saw mill.
I have a Chevy 4.1 lt I 6 motor powering a 80kva alternator producing about 25kw.
In my opinion if you need the reliability nessary for a hospital a diesel generator will be the best, but you run it as a duel fuel system.
You start and run on diesel but you add wood gas once running, the governor will back off on the diesel until you are using a little mor than an idle. The main power will be comming from the wood gas. If and when you have a problem with the gasifier the diesel will take over and you won’t be left in the dark with a patent on the table !

Just my 2 cents worth.
Thanks Patrick

Hi David;
It’s not impossible to get a genset to run on woodgas. You just need a properiy built and operated Gasifier. I have a propane Onan genset converted to woodgas and it runs well. My unit is rated 13kw on propane and so far on woodgas i’ve hit 9.2 kw. My Youtube channel is If you would like to see video’s. Dan

Hi there!!

First of all, thanks for your answers!

Patrick, I have hear this dual fuel system, which uses diesel for ignition and for idle…
As far as I know the changes in this engine to work with syngas are:

  • Installation of syngas feeding system
  • Modification of inlet valve to allow smal quantity of diesel entering the chamber. (I heard something from a kind of governor from woodward)
  • Reduce the compression ratio to 16 (removing material from heads of the pistons)

Do you know if this is right and it if is “easy” to do it? Maybe is something that an expert mechanic can do…


Reading your reply I guess “properiy built and operated Gasifier” a gasifier capable to supply good and clean gas…
Did you modify the propane genset somehow to adapt it to woodgas? It’s interesting you only lose 3.8 kW.
It seems that modifications could be quite easier than a diesel engine only by the fact it works with gas fluid.

Sorry for my big response and thank you both!!!


Seems like it would be much easier to add a second (or third) head gasket and longer head bolts (if necessary) to reduce compression rather than machining pistons.

If you search for a turbo charged Diesel engine you will find they have a lower compression ratio. Woodgas will run well at 17 to 1 compression, if you can find an engine around 2 to 2.5 litres running it at 1800 or 1500 rpm will give you the power you require.

A lot of work has been done on using Diesel to ignite the gas but it is not successful, look at adding spark ignition to the engine.

Simplest way is to find a generator designed to run on natural gas, the compression ratio will not be as high as the ideal 17 to 1. but conversion to woodgas is very simple by just adding a valve to control the intake of fresh air to control the mixture. Search for information on woodgas carburettor and you will find lots of examples, it is really simple.

Hi Gary,

Thanks for your answer.
Do you know companies which sell GN gensets?


Hi David,

The major manufacturers make large ones but I am not sure in the power range you are looking at. I would try google and also Ebay etc as they would not be highly sort after you may pickup a bargain if you are patient.