Old Swedish inspection regulations for woodgas powered vehicles

Hi, here im going to post some regulations that was used by Swedish vehicle inspections.
This was old regulations from 1940-41, revised when oil crisises made woodgas an interesting alternative, I think this was revised 1953, 1974, 1984?, this is the last from 22 of january 2001, when ALL regulations was revised.
This comes from Swedish vehicle inspection services technical handbook-motorized vehicles.
I hope my translation is understandable.
Even if this are not current regulations, they could be taken as a good “rule of thumb” referring to avoiding risks of fire or carbon monoxide poisoning.

Mounting of gasifier should be made in that way that gas leaking into passenger compartment is avoided.
Open crankcase ventilation can NOT discharge into engine compartment, in that case it should be re-routed.
Floor and wall between engine; and passenger compartment should be as sealed up, as possible.

Gasifier and equipment should be mounted in a way that risk of fire is avoided.
If distance between gasifier and combustible part of vehicle is less than 16 inch, an insulating wall should be mounted.
Wooden parts of vehicle should be covered with a layer of sheet metal on side against gasifier.

Distance between gasifier and insulating wall could not be less than 4", if it’s less than 6", an heat shield should be mounted in between.
Distance between heat shield and gasifier; or insulating wall, could not be less than 2".

Gap between gasifier and heat shield or insulating wall should be covered with metal net, to avoid wooden fuel spill getting stuck in between, and to make air circulation possible.

When gasifier is mounted in trunk, or cargo space, sufficient air circulation should be allowed.
Trunk lid could NOT be replaced by a lid made of combustible material.

In my translation i have omitted some parts where text “repeats itself” (this is written in a very “bureaucratic” way)
There is more to come, this is just from first paper of six.


Thanks Göran,
I am working on a document that I can show to insurance, licencing and maybe police people here in the US. I should have documents in Swedish (or other original language) with very good translations. Maybe this will contribute to legal acceptance of this technology. I used google translate for @JO_Olsson’s documents, but I have to make them clear. I welcome your translation, but I need original Swedish documents too.
I think we should not have to hide.


Thanks Rindert, ofcourse im going to post the originals, only thing is they are very blurry, hard to read, probably 10th generation photocopies.
Best thing would be if i could scan them, and maybe e-mail them to you?
Anyways im going to take the best pic’s im capable of and post them here. :slightly_smiling_face:


Interesting. Althugh l dont quite get no1…

Edit Ah, l see. Probably to prevent CO rich blowby to enter the engine bay and then the cabbin


Yes Kristijan, it’s right on spot, i think we often forget the dangers of blow-by gases, that are actually over-pressure and possible to leak, when engine is running, i read in some report, that blow-by gases in a woodgas engine had been measured to contain up to 30-40% carbon monoxide, due to slow burning and heavily loaded engines.
Not to forget, when this regulations was first written there was no such things as closed, or negative/positive crankcase ventilation, often a pipe down under engine, that with a “tired” engine often smoke as much as the exhaust pipe.
Little history: during the war, at woodgas vehicles, the crankcase ventilation was often extended to the rear of the car, without correct slope/inclination there became water-pockets that froze wintertime, that led to every axle seal being shot.
Sorry for this long posting :roll_eyes:


Interesting, thanks!


Yes Positive Crankcase Ventilation was the first and Mother of IC engine emissions control. 1967.
Easy to do in concept, to route the crankcase vapors into the intake stream; intake manifold sucked and let the engine burn them up.
In real life practice?
Many issues to deal with.
First a flow variable valve (the PCV valve) had to be developed to keep too large of flow from sucking at engine idle upsetting carburetor air-fuel idler ratios. These gum up and stick from the crankcase crud. Water vapors from the crankcase can freeze as Goran said. So some systems had to be added complexity, coolant warmed. The hoses connecting are exposed to high levels of warm acid vapors and deteriorate. The best systems incorporate a fresh air make up routed back into the opposide side of the crankcase using filtered air from the air cleaner housing. American systems. They truly are positively ventilating, cleaning, the crankcase oil. Oil’s stay cleaner longer. Hurrah. The intake passageways and intake backside valve heads build up oily deposit accumulations flow blocking air and fuels. Boo.
Many of the Japanese/Asian and European systems from the 1970’s throughout the early 2000’s are not true positive ventilating.
No make up air allowed. No sweeping cleaning flows inside the engine. They just Tee flow out when positive pressure builds up in the crankcase. With that pressurized flow then not being vented to the atmosphere. Polluting the environment. Meets the letter of the laws.
Not truly crankcase positively flow ventilating this created the internal slugging up engines models Toyota, VW and Audi, and others produced too often. Owners were blmed for not changing the engine oils. Bullshit. Bad designing.
I saw this oil get dirty quick way back on my bought new 1987 Suzuki Samurai. My solution was to route fresh air from the air cleaner housing by hose in through the dipstick tube. The actual dip stick removed and under hood stored in its own hose length socket to stay clean.

Using the engine intake suction as the gasifier system flow sucker you must bypass, defeat the factory PCV systems and go back old-school to just natural draft crankcase venting.
And you just broke the USofA, EPA factory emmisions system anti-tampering law. Broke many States factory emission systems laws too.
Mums the word here.
Do what you must to make it work for you.

Yes I do tear off all annoying, scratchy pillows, blankets, and fabrics labels too. Lock me up and throw away the keys.
Steve Unruh


I never had much of an issue with my PCV hose remaining connected on the Mazda. Though my valve cover breather was open to the air with a filter to keep dirt out as well.

Is that okay for the engine to leave the PCV as is but the valve cover not going to Manifold or air cleaner?

Best should be to connect it to air cleaner, to get cleaned air, and if suction/ pcv dont keep up, any blow-by gases end up in air cleaner to be sucked into engine and burned.


the American term here we call it the slobber tube :grin:


In Sweden the oil/moisture “goo” that comes from crankcase vent often are referred to as: “mayonnaise” :stuck_out_tongue_closed_eyes:


Here comes the regulation papers untranslated, sorry for the bad quality, this are probably, photocopied, fax-ed, and e-mailed, at at time when you couldnt use telephone and internet at the same time. :roll_eyes:

Page 1

Page 2

Page 3

Page 4

Page 5

Page 6


Some more translation:

Ashbox, made of non-combustible material, with well-sealing lid, atleast 8" deep, and with a width, equal or more, of width of ash clean-out port; should be carried on woodgas powered vehicle, at a stipulated place, out of way of combustible parts of vehicle.
At local, public transport, the ashbox could be omitted, if sufficient equipment are placed along the route.

Poker and ash-rake should be carried, in a fire-safe manner, outside the vehicle.


Fire Extinguisher must be a minimum of 25kg and contain propellant. You may substitute the equivalent carbonated beverages such as beer. (The beverage may be appropriately processed if you are either Canadian and/or familiar with the movie Strange Brew. )

1 Like

I’m a bit of a Constitutionalist. Having said that, in the US we are guaranteed use of our highway systems unhindered in any way for private use. That means if I wanted too I could mount a 454 in a little red wagon and speed off down the road if I so choose. Be careful about talking or agreeing to any kind of regulations about stuff like this. The Government only does one thing well and that’s make itself bigger. We both know that once you give up a right to a tyrannical government you will never get it back without bloodshed.


Errrr. I agree there is such a thing as bad government, bad laws, regulations & etc… I served in the USMC and could still pick up a rifle and do something if necessary. Sic semper tyrannis!
And I like to think I can regulate myself. I like to think I live by principles, not rules. But I know that even I have been mistaken from time to time and have had to have things explained to me. LOL
But I have known several people who justify the things they do by saying “it is not illegal” or “don’t do that or you’ll go to prison”. These people live by rules. I may not like them but I’m a fool if I pretend they are not around.
We are going to have rules, laws, regulations, whatever. But they can be clearly worded and they can make sense. Too many of our laws don’t. If people like you and me get ahead of the game and have our [email protected]# together in advance. Heck, if we do this real well we might even become known as ‘the good guys’. Wouldn’t that be worth something? I see a huge opportunity here to promote the use of wood as transportation fuel. And there is no good reason we should have to hide what we do.

Btw, I wouldn’t take your little red wagon away even if I could, as long as you don’t endanger others. And if you want to do crazy stuff, blow yourself up, make a big noise and a bad smell, well there are places where you can do that, such as race tracks & etc. Just sign a waiver saying that you can’t sue. Ain’t America great!!!


I think your on the right track Rindert, if you could show, look here; other countries have rules and regulations for this stuff, it’s known technology, it should made it harder for authorities to just say; i dont understand this junk you mounted at your truck, easiest is to say its totally illegal!


Thanks Göran. You’re in Sweden, aren’t you? Here in the US we tend to have a negative attitude toward government. And yes, there are quite a few cases where our government has let us down. I know that it is not like this everywhere. My relatives in Netherlands have a very different attitude. However, the way I see it government is there for me. Heck I pay for it with my taxes. And for the most part this is actually true. I love to read the constitution of the United States, for instance. The language it’s written in doesn’t bother me, since I grew up reading the King James version of the Bible after supper every night. Why can’t all our laws be clearly written and make sense like that?
The only answer I find to that question is that we just don’t put in the time and effort to make it so.


Yes, im from Sweden, and i think we are much alike in attitude to our “governments”, anyway in Sweden it seems like people on the countryside are much of this opinion.
Anyway i meant about regulations and rules on smaller scale, as in local vehicle inspections or roadside inspections by traffic police, seems to me they often classifying things as “illegal” if they dont care about checking things up.
Anyway authority persons always like papers and regulations right?


My experience is that only a few people are actually bad. And people in government are no different. My strategy is to ‘play it straight’, as we say in the US. It is hard at first, but once they figure out that you don’t want to cheat, and want to actually ‘do the right thing’ one or a few of them may come forward to help you. That’s when the hard work starts. Don’t screw up your relations with these people, they are the ‘good guys’. Work, and work, and work. You actually can get things done sometimes. But realize that none wins all the time. Be ready to recover and do it again. Life is hard, but good.