Jan, the gasifier breathes easily. No high hopper vacuum readings. The tary crust in the preheat area was irrelevant information. Almost impossible to avoid smoke backing out at shutdown. Happens to any wood gasifier.
There’s only one more place to look for burning leaks - and that’s the crossover section. I would hate to cut it apart though. The gasifier will end up looking like Frankenstein’s monster when I’m finished patching it up.
Ok, I did that kind of intake on the air with a flap that falls back when you release the throttle, the diameter was the same as I had before and the flap went very easily, but removed it after the first uphill, the car did not run well at all, with that resistance on the intake air.
Hi JO, I followed your thread back to the beginning, but there is no picture anywhere showing the fresh air supply pipes from the heat exchanger to the hot zone, well, if these joints are welded, there is considerable expansion due to the high temperature and therefore large forces between the inner tubes and the outer casing, which could cause cracks in the material.
The wood gasifier still produces a lot of gas when we stop the engine, the only way to prevent the tar gases from spreading through the fresh air pipeline and the wood gas pipeline is to close these pipelines somewhere airtight, and open the chimney, which is installed on top of the gasifier, it must not be too large, for this size of the gasifier, a diameter of 1" is sufficient, this will prevent the deposition of tar in the system.
Tone, the air travels from the heatexchanger to the gasifier via a 12×12×2" finned path/slot/void/gap on top of the crossover.
I agree with all you mentioned. Even a hopper chimney obviously works well on something like a tractor. But on the car or the truck, parking in town, I would be afraid the smoke would repell female admirer. We can’t have that 
The female admirer you want to attract, most likely enjoys the rustic smokey smell. The smoke is repelling all the attention from unwanted females.
JO, I’m really glad we can talk about the wood gasifier and its features again, don’t get me wrong, I’m not going to spare you the problems you’re having. When building the gasifier, I adhere to the principle that it is built simply, so that I can quickly dismantle it, the hot zone is just placed in the bed and sealed with ash, and below it is attached with a non-return valve for the air supply. It will be interesting to see pictures, if you post them, how you connected the air to the hot zone.
When the wood gasifier is heated and full of wood, it produces combustible gas for quite some time (10-15 minutes), which burns nicely at the outlet through the chimney, if we add a larger pipe at the top, which is open at the bottom, the flame burns “intimately” in this pipe. and the wind doesn’t bother him. If the gas is not released at the top, it will spread throughout the system, cool and condense on the cold surfaces of the cooler and filter, but some of it will still escape into the environment. The hot zone with charcoal cools down faster because it is cooled by humid gases and not only cools, but also eats up the charcoal, you can notice that when you restart the gasifier, the contents of the hopper collapse quite a bit. Lately, I’ve tried short stops (10-15 minutes) when I was digging and loading soil, by turning off the engine and opening the chimney, then restarting on 100% wood gas and driving, after about a minute of operation, the engine was a bit tired. but he quickly recovered, well, if the tractor stood for half an hour, he needed the help of diesel fuel.
I can’t tell you how much I liked reading this line Tone. Not that I know exactly what you are describing but because you are “intimately” aware of things that is outside the scope of what us " weld it together and hope for the best" builders can understand. I would enjoy being in your company and I don’t like hardly anyone. 
J.O.,
Almost looks like there could be some “termite” holes here? Hard to tell, may just be shadows. 
Hi Tone, unfortunately this is a welded shut gasifier. I hope you can make heads and tails outof these pics and figure out the air path.
I think hes got a copper spiral tube hidden there somewhere 
Mike, I’m sorry, somehow I missed your post last session. A shadow behind a small lump of weld it is. I’ve examined that critical joint all around with my sharpest reading glasses and I find nothing wrong with it.
Told wife I’ve come to a critical point in my investigation and I don’t want to be disturbed. I filled the crossover air path with half a gallon of water and waiting for any water to drip down into the dropbox section. Two hours and nothing so far. Hard work
If you had another chair I could help 
Nice shop. Looks like you could eat off the floor. You probably know where everything is as well. Your making me feel bad about myself. 
Thinking about making a new unit, and have looked at the ones you have made for the mazda and volvo,
How do these work, they are quite different, is there a big difference between driving the mazda and the volvo at low revs, or both at high revs?
Jan, the Mazda thrives at relativly low power. Rapid responce, good idle and not picky at all about the air-mix. Not much different from running gasoline.
But in the other end of the spectrum it lacks some power. No point at all reving more than 3000 rpm. 80-90 km/h at 2500 rpm is ok for about half an hour, but after that the charbed can get dangerously coarse. Ideal then is smaller fuel or charcoal added (rocket fuel).
While the Mazda’s gasifier has internal dimentions on the small side, the Volvo gasifier has the opposite. The Volvo runs the best when it can really stretch its legs. The idle isn’t 100% reliable and when accellerating from there I experience severe hesitation sympthomes for the first 5-10 seconds.
I had quite frekvent problems with the throttle not moving freely until I mounted those three lower nozzles. Obviously that huge charbed couldn’t keep the heat up at low demand.
Excellent J.O.
“Compare and Contrast” is reality based.
Too much Idealism in the alt-energy and DIY endeavors. That leads to snipped, edited all’s-well books and YouTubes. When reality all-is-not well&easy. But instead plenty good enough. Useable by a willing to work it Owner-Operator.
Good C&C is an antidote to the Idealism spin-head, bobble-head games.
Regards
Steve Unruh
Thanks JO, I thought you would say exactly that when I looked at the drawings of your units, I think I understand then why you hesitate and that the volvo runs worse at low revs, thanks.
I need a unit for the Saab engine I have in the garage, I’m thinking about whether I should make one that fits the Chevan and take the Chevans to the Saab, it’s probably a suitable size.
Is the Saab engine a replacement for the Iller, or something else?
