Kristijan, I have a grate, but it does not cover the entire space, maybe I should put in a ring that holds the carbon better.
Mayby i should put in bigger coal.
Excuse my bad English.
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Now I have put a ring on the grate so that the carbon does not roll down to the bottom.
How should I drive the car so that it does not carry carbon to the cyclone when I have an automatic box?
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In the first picture, is the grate resting on the charcoal that carried off the grate, or through the grate? What is the diameter of your grate? With your size engine at 2000 rpm, the velocity I think is somewhere around 35 litres per second. That will carry a lot of light charcoal. How close to your reduction is the grate? I hope it does not plug up with that ring.
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Jan, I admire your persistence 
Slowly Just try keep as low rpm as possible. Open up the air valve and add gasoline if youāre in a hurry. Thereās no way this little gasifier can satisfy a 4.2L engine at WOT.
With reasonable power demand and enough empty space below the grate char will stay put. As soon as char shows up in the cyclone you know that space is probably full and time to rake out.
Hard to tell from the pics but your grate may have somewhat wide slots. Drive very carefully for a couple hoppers and let things settle. Ash and soot will fill any unnecessary voids. Try not to disturbe the charbed, apart from careful cleanouts.
Thatās all I can think of for now.
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The roster is on the macadame (ground) just to show how it looks.
The second picture is from the inside, from below.
The ring is about 16-18 ā.
The gap between ring and reduction will probably be 7-8ā but to the 9" pipe ca 3-4".
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Jan;
The gap between the bars in the grate (roster) are too far apart-- especially the center gap. I have run two different grates in mine; both worked well. The simplest to explain was made out of 3/8 rebar. Made a circle about 9" in dia, then welded my bars to it. Spaced the bars with a 3/8" gap between themā¦ Picture at about posting 196
Posting197; it looks like you have 10 nozzles in there???
Posting 215; I would definitely go with JOās inner hopper. Yours looks like it would send the radiant heat right from the nozzles ( oxidation zone) up to your lid. JOās the radiant heat can spread out and be absorbed, before it reaches the top or lid.
Posting 230; Unless you get Mr. Wayneās book and want to start an entirely new build, I suggest you forget about trying to make your Imbert work like a WK. I just ruined my engine doing exactly that. With my version, it ran better than I could have ever hoped it would run on woodgas. BUT-- tarred my engine up. (this was NOT by WKās design)
Posting 234; JO has mentioned a couple of times that yours is a āsmallā imbert. Yet you say your dimensions equal mine. Mine, I would say was closely built by the book.
Posting 246; You say the ring is about 16-18". I assume that is in circumference(5-6"dia). From the picture then, your entire grate is too small. It should be atleast the same as the 9" pipe. Then mount the grate right up against the 9" pipe bottom. āThe gap between ring and reduction will probably be 7-8"ā. Do you mean gap between ring and RESTRICTION will probably be 7-8"?? If I am picturing your gasifier correctly, that will make your reduction zone the lower part of a pyramid with a 9" base and 7-8" high, which may still be too big.
TomC
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Hi Tom, thank you for writing, yes you and I have pretty much same size of the unit, apart from my 9 ātube.
How fast do you usually drive with your car, and how much wood did it eat per mile?
I still think I have a leak somewhere that burns some of my gas.
Now your questions
yes, I also built it after the book, the difference is the 9 ātube instead of a 12-13ā tube, and I think it is the error that the wood does not run down,
I think the gap between the bars is about 3/8- 1/2ā.
post 196, No it is the cone you see, i have 5x10mm nozzles, holes you see is for the cirkulation.
pos 215 i tested to do a cone with 45 degrees like JO, but it wasnt better for the bridge or for the temp.
post 230 i only curious of the WK , because of missing of tar with the big restriction.
post 234 I have also tried to build mine after the book, but think I have too small nozzles and fire pipes.
post 246 The ring is 16-18" in dia, yes you have right, it is between restriction and grate.
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A little interesting, went about 30 km last night in the forest, was barely over 1500rpm.
This morning the throttle was almost solid, had some pine and spruce in value, but no more than about 15%.
First picture is the ash in the cyclone, second from the hopper.
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Good morning Jan; First I want to say, I am not as knowledgeable as a few of the others that have been advising you. I am just looking at the one that worked best for me and comparing yours. My truck had no speed-o so I donāt know how fast it went or how far. I drove on the interstate and did not pass too many cars but I kept up.
What do you mean? You couldnāt push the accelerator pedal down with your toe? The stuff you got out of the cyclone was āperfectā. Just what you should always get. I suspect driving at a slower speed didnāt make so much gas speed across your char on the grate, and only picked up the fine material. The stuff you got out of the āhopperā was way too big in many cases. That was gas that you ānever madeā not that leaked out or burned in the system.
First I want to repeat myself and say, āforget about the WK design.ā It is a totally different thing. I ran a 9" fire tube. If you look back at post 196, the first picture you will see that my ānozzle tip circleā is 9". In the second picture you will see that I put a shroud over the nozzles which made my āfire tubeā also 9"; just even with the nozzle tips. With your 9" fire tube, make your nozzles as short as possible so the nozzle circle will be as close as possible to the 9" mark. ( 9" is not the utopia for nozzle circles. Iām just trying to work within the fire tube you have.) Make your nozzles as long as possible, and still maintaining as close to as possible the nozzle circle. Grind the threads off the first part of the nozzles so they stick into the air chamber before the threads pick up. This will give you more velocity to your air in the oxidation process.
Now back to the grate. From your picture and the dimension you have given me, I āthinkā you have about 1 inch between the bars. That is allowing the large char chunks to fall through. Like I say I donāt know everything, but make that simple grate I suggested or something similar. Those chunks when they hit the grate they are red hot and the air coming through the restriction hits them and makes woodgas. If the red hot char falls through the grate it just lays down there and cools off below the temperature that would make gas.
Next with a new grate, I strongly suggest mounting it up tight to the bottom of the 9" fire tube. With it hanging so low, the velocity of the gas coming through the restriction and through the reduction zone, is fast enough to blow the char off the top of the āchar coneā that forms on the grate. At high speeds you have just proved that this velocity is carrying it up into the cyclone. The grate has to hold the hot char right up in the reduction zone. There the velocity is forced straight through the red hot char, making it into gas. As this char makes gas, it gets smaller and smaller until it falls through the grate making room for more red hot char. Bean size char in the ash pit is good.
I think I had something else to say, but my memory fails me a lot lately. (keep that in mind as you read what I write). TomC.
Oh! PS I still donāt like the inside of your hopper. You are wasting space for wood.
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Thanks for your advice Tom.
Think itās very interesting, because you have similar things to me.
What bothers me is that I was able to drive the car at 100kmt (60mph) before, although I almost always drive at 70-80kmh.
Therefore, I think I have a leak.
Yes, the throttle was stuck this morning, probably because I drove so slow for so long.
My Hopper is clean, no funnel at the moment, it seems to be the best.
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Hello again Jan. I donāt know how to proceed here. I donāt want you to think Iām a know it all. I fear that if I say much more and my suggestions donāt work, Iām going to appear to just be some loud-mouth. But after reading your last post I feel more convinced that I have been on the right path for you.
So the throttle stuck. You made tar. Tar is generally made when you āunder pulll the unit. Driving slow yesterday was āunder pullingā it. Now we know you donāt want to drive slow all the time, but if you speed up you pull char into the cyclone along with lack of power. To me, this is all proving my point. You need a new grate as discribed, mounted up against the bottom of the 9ā fire tube. A new grate will hold the red hot char from falling through. Putting it up against the fire tube forces the air/gases THROUGH the red hot char pyramid on the grate instead of blowing off the sides of the pyramid. With the air/gases going THROUGH the hot char, you will make more gas from the hot char before it drops through the grate. Forcing the air/gas to go THROUGH the red hot char will break down the TAR into more gas.
Good luck. I am probably going to bale out now, hoping that the other guys will jump in and tell you if I am wrong before you spend to much time re-doing things.TomC
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Ha, I guess in writing, we all struggle with this issue trying to give advice 
Iām convinced we all made tar at some point, but
with both my gasifierās being on the small side I donāt think I have ever made tar driving too slowly or idling for too long.
However, pushing the gasifier too hard, burning all the fines and slipping char faster than it can be made, are probably the main reasons for my sticky throttle events.
Jan, Iām trying to point out the possibility your tar was made because of what happened the day before. When your cyclone suddenly was filled with 10L of char itās possible raw wood passed your heart faster than it could be properly charred.
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I donāt know much at all, but I think I know how this stuff works, (in the gasifier inside my thick skull). I think Kristijanās grate-less worked well because the glowing char was confined in a small space and acted like an extra-large reduction zone. I think J.O.'s works about the same way, char has more area to spread but is still confined. Jan A., I think Tom C. is right. Your char bed escapes and needs to be confined, (like with a grate) keeping a proper reduction zone. Your char escapes into the cyclone , (before making a solid, continuous, hot char bed) being too cold to react there, and your reduction zone gets compromised. Finding the right grate design and distance from nozzle ring will be the trick. Like Tom mentioned, I think the cast iron grille openings are too big.
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Hi Jan, After looking at your grate, I agree with Tom, and the others, those are some big lots in the grate. I have a down draft charcoal making retort and my grate for dropping the cooked charcoal into the catch camber has opens that big.
I would suggest you could take a piece of steel plating cut to the size of your grate with holes drilled into the plate and place it onto the grate the side ring will hold it in place. This will keep the larger pieces of charcoal up in the reduction zone where they need to be for the gases to convert to H2 and Co. From the picture that I hear you said about driving with to rich or to lean gas you are losing your charcoal bed on harder vaccum pulls. I would think you would only need about 3/4 or less of the grate spacing you have now. You could keep drilling the holes out larger until you find the right size for your grate opening for operations and to slip the smaller charcoal pieces and ash.
With the side ring in place do you have a 3/4" gap between lower pipe of the reduction zone and the top of the grate ring?
Bob
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Hey ,yeah.
Drop on grate plates works great.
Iād suggest though grind slotting that plate with slots instead of drilled holes if the object is to keep the most char chunks in the hottest active area.
As BobMac says open up the slots widths until you get the results that you want.
Go too far, too big? Make another plate slotting that one back to your best results.
Regards
Steve unruh
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Was out and drove 30 km the day before yesterday after putting the ring on the grate, the first picture soot from cyclone the second jumper.
Went about 15km in 70kmh 15km in 30kmh.
Checked the grate there are about 15 mm gaps.
But divided the pieces of wood into smaller pieces, and they were wet inside, can explain the heat at the top of the jumper, gets hot from the steam.
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Can explain the low power and sticky throttle as well. Wet wood will steal a lot of heat to steam off the moisture. The wood can never get too dry.
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Tried smaller pieces of wood this morning, it seems like I can run earlier on the gas, and it does not get as hot in the jumper.
Nor was there a bridge that I needed to do anything about.
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Found this I think it is very good information
the wood needed to be cut into chunks no bigger than three inches long and two inches in diameter. It needed to be dry, meaning it had to be cut at least six months prior to being burned and stored out of the rain. Finally, hardwoods like birch and oak were preferable, while resinous woods such as cypress were to be avoided.
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How do you seal the ashtray?
And do you have any clever way to check if the whole system is tight?
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