Woodgased BCS walkbehind

Thod l alredy started this topic, but it seems l did only in my head.

Its haying season, and time to fuel up the old BCS hay cutter. Went shoping the other day and on the shoping list was “petrol”, ment for the old BCS. I drove right past the gas station, out of principle! Spent 2 afternoons on converting it to woodgas rather thain paying for the 100% overpriced gas.

I will go more in details when l get more time but for now, l leave you guys with a short video


Was this for the hearth you posted earlier?


Correct Cody!

Its a true downdraft, ment for charcoal but able to be quickly converted to wood chip if needs be.

On the other post l mentioned the size. The engine is a slow turning 0.5l-ish engine (a bit less) so l designed it for the low consumption rate. I hadnt made anything this small in years. But it was great fun. The engine literaly started on the first pull, with the gasifier hot. This engine loves woodgas!


Is it an Overhead Valve engine or Flathead?

I need to get my walk behind brush mower fixed.


Okay enough with the walk behind tractor teaser video on char gas. I hope you video the whole build of this new down draft gasifier and have a drawing or two It looks pretty KISS to me. Now I will not be able to sleep tonight waiting.


Looks good brother! :smiley: :smiley: :+1: :+1:
I think you just set the record for fastest gasifier build.


Slow down guys, cant keep up this way. Wich other post?

Very interesting


Its a flat head, fairly low compression. Ment to run on kerosene. When l visit Tone he offered to shave the head off for me, shuld run even better.

Bob, its 5.18 in the morning and time to make our animals some hay. Will try to show whats going on here


No problem Family first, animals, job, and other important things you have to do will always come first, you know me just making fun with you. About 12 hours difference in time too.


Jakob, the original plan was to throw on a litle “throw together” gasifier, simple fire style, then l decided to make something better and longer lasting. Took quite a long time actualy as its super simple, but its all made out of oil barrel steel so welding is slow. Its super light weight thugh, the whole thing weights maybee 10 pounds empty.


Been working the machine some, now time for a breakfast break and l uploaded the videos.

Runs good, just as it wuld on petrol minus the power loss ofcorse. It seems this engines governor realy likes woodgas! It stalls sometimes on petrol because the governor is too fast and the carb is primitive and cant respond. So let be correct my self. It runs BETTER on chargas.

Bigest surprice is fuel consumption. Those engines are fuel hogs. They devour fuel by the gallons. So l expected the same with charcoal and planed for a 15min refueling interval with this tiny 2 gallon-ish hopper. Ran for half a hour and only burned half of the hopper! So one hour run time shuldnt be a problem, however for safetys sake l will probably refuel in half hour intervals.


Great work as always, Kristijan, i like it :smiley:


Excellent build, Kristijan.
With your 30% moisture content, how about downstream condensation? Also, I’m amazed the short outlet pipe before entering the filter is enough not to melt the plastic.


Kristijan , I am most impressed with how well it seems to run for you with little to no cooling , very clever downdraft design it will be interesting to see it completed when you get some more gas for the welder and hope to see it running on a mix of wood and charcoal , please do let us know more about the dimensions of your grate i sort worked it out too around 144 mm Dia but not sure for definite .


Thanks guys.

Spent the whole morning working the machine. Only one hickup.

I thod it might be better to throw away the wet towel from the pipe before the filter, thod heat might radiate off better. Well, it did not. I melted the filter, partialy. Plastic got soft and vacuum shrunk it, so the seals no longer held. Fixed it with applying some inner tire bands over the sems and reaplying the wetened towel. Ran flawless ever since.

The other “hickup” is since this gasifier is so small, it cools down extremely fast once the motor is stoped. The bateries on my fan are in poor health and there is no way of pullstarting the gasifier with the engine runing on petrol (hooked it up on a bottle of petrol). I need to install a manual air pump to be able to start the gasifier without any external help, anywhere. Walking home and back to the hayfeald to charge the fan is more tyreing thain the mowing…

But once its goind, it just needs a air setting at the start and refuel every half hour. This is probably my best working project yet.

JO, no condensation downstream that l culd notice everything is dry down there.

Dave, this will probably never run on wood. When l sayd its a true Imbert in the video, l was wrong. Its lmbert-ish. It has no restriction. No need for it when runing wet charcoal, no restriction, less drag, more power… and with such a low compression slow engine you need every bit of power you can get.

Dimensions. Sorry, l didnt measure. Nozzle circle is in the neighbourhood of 4", grate diameter maybee 6", grate made of 8mm rebar about half inch apart, fixed grate. No restriction, nozzles protrude about an inch inward.


Thanks Kristijan , just one more measurement the height of your nozzles above the grate , very hard for me to guess in the photo , and it also looks like the nozzle at 11 o’clock is pointing downwards or just might be my lazy eye playing tricks again :grinning:



No, they are all in one plane.

I wuld say about 5 or 5 or 6" also.


Great work, @KristijanL. You aspire for KISS gold medal.

What Is the mean to adjust power? Do you just open the throtle valve?


Or a gotter’done kiss from his wife? Or maybe from his goats. Never both.
I am just so jealous of his nice durable hardwood charcoal.