I was concerned about the size of your chunks going through the restriction, but if by the time it passes the nozzles it is down to pea size, that certainly is no problem. BUT, now I wonder how the char is getting so small so fast? Is it too much oxidation, or is the reduction starting that early and almost playing out by the time it gets to your grate. That would explain why you had to raise your grate. Just thinking as I write, would larger nozzle diameters increase the oxidation and give more heat to the char to keep the reduction going deeper into the grate??. Honestly, it is running so well that I wouldn’t worry about anything until you actual see a problem.
I of course am envious of your build as I am of Don Mannes, because I feel like I am driving a semi when I drive my big clunker. I am trying to follow your and Mr. Max’s conversation on cooling tubes and condensate tanks. I could take a lot of weight off my truck if I got rid of my big preheater and those 4" horizontal cooling pipes. TomC
Hi, Jan-Ola and Tom!
24. of july 2016
This latest note triggers me to repeat:
The upper hearth is 1,67 times the volume it would optimally have for 1/2 cigarett pack fuel size.
Photographing skim after skim downwards can tell the bit size and the change in color, dull / shining, as free oxygen finishes…
Nozzle-tip-circle … 6.6929" = 170 mm
Height,
Restriction >> nozzle plane … 2.62" = 66,5 mm
Rising the restriction, to new higher position
and diameter … 3.5" = 88,9 mm
The restriction could be an ID 3.5" full-threaded nippel in
a flat nut, welded on the restriction plane… SS
The volume … 903,844 cm3 = ~ 0,9 liter, or some less than 2 pints
The coolig steps need considering.
That’s it for now.
8-10L (8-10%).
1L of water is 1kg. Don’t you just love metric 
Latest news:
Just got home from a 40km (25 miles) trip. Ran like a champ. Crused at 50-60 mph on the big road mile after mile with little effort, less than 1/4 throttle at a steady 8:4 in. vacuum. These speeds I usually struggle to keep sometimes pulling close to 40 in. with a flat hayfilter.
So what is done?
Grate is raised another inch. It’s now at 4" below restriction top.
Restriction insert is gone and I’m now running 3.5".
I also built a manual grate shaker, but with this ratio there is no need for it.
My first test run was yesterday evening and I started to get back to 5:1 even 6:1, but that was with my old fuel (50% of it more like yolks than whole eggs).
Today I sorted out some bigger fuel from my new batch that is not even properly dried yet. After only a couple of miles i was down to 2:1. Temps are about the same, maybe a little higher.
Thanks Max and sorry Arvid for not believing in your short reduction suggestions.
These are pictures from yesterdays event:
Below insert is removed:
Reduction and grate plugged big time.
We live, we learn…
Good to hear it’s coming together
Great to read such positive resaults!
Is that slag on the grate? it looks like my charcoal gasifier slagA!
l have a cuple of questions about your build if you dont mind.
What is your hopper volume?
What is your fuel consumption at 60 mph cruze?
What is the hopper temperature?
Hope you dont mind the curiousity 
his wood will be around 15 to 20% (european standard for carpenter lumber)
1 liter is 1 kg 
saturated air at ambient temperature, about 3 grams water per 1000 liters air, ( 1 cbm)
saturated air at 80°C almost 200 grams
i love headaches
Jo,
great job… join the LOS (land of smiling…)
LOST= Land Of Smiling Travelers. 
Please, go ahead ask.That’s what this forum is all about.
No, i think it’s only a mix of ash and very small char (dust). Falls easily apart like wet sand that has dried up. The whole reduction was filled with it. Only wormholes left for the gas to travel through. Didn’t even come out by itsef when I removed the grate.
Only 45 cm high (18") and 40 cm dia (16"). About 5 cm around the perimeter (2") is monorator void. Usable space for wood is only 30 cm dia (12") and 40 cm (16") mm hight. That’s 28 L or 7.4 gallon. About the volume of a short WK firetube
One hopper takes me about 40 km (25 miles). Most of my wood is bulky alder. A full hopper of that ways 6-8 kg (13-18 pounds). That means 1,5 -2kg/10km (0.5-0.7 ppm or 1.4-1.9 mpp). I haven’t seen any differences on light or heavy load yet. It kind of runs for half an hour no matter what.
As long as there are wood above the funnel area it stays at around 80 C (176 F). I run it no more than until 150 C (302 F). Not because the wood is to low but tar is getting hot and temp climbs very fast above that temp. My probe is at the very top of the void.
Hello, Jan-Ola!
25. of July 2016
By all means, Tank you!
It seems the lower part starts to handle its task as expected!
The upper part is still about 1,6 times as big as half cigarett paks need, comprising of an char-coke cone and a flat “WK cylinder” upon it.
This seems to be successfully circulating the pyrolyse gases and keeping the returnloops around the nozzles free and dry from tar-coking.
It may now handle fuel bits of a tennisball size.
If a newer set of pictures show changes in the upper part, please show the new pictures!
If “flattening” is needed, the threaded 3.5" ID nippel in a welded-on flat nut is a handy way of regulating the cone height.
Yes, that’s the size of the biggest ones I used. Probably the very upper limit. They are after all going down into an 8" firetube. I remembed the old rule of 1/4 of firetube dia for a maximum.
Going back to work shortly. If there are any further changes done I’ll let you all know. This has been a different kind of vacation. (To my wife that is)
Thank you so much again.
Rick Bates, where are you? Now I have done it.
I was planing for a longer trip today and I thought it might be a good idea to flush out the coolers before I left. I put the hose into the top of them and started flushing. I remembered I didn’t open the outlet on the condence tank but decided to wait until it filled up, for even better cleaning.
I flushed and flushed with my mind on other things. Suddenly I saw a couple of drops coming out of my bottom lid on the cyclone collector and I knew water had started to rise and flow into my cyclone. Well, I had to empty it anyway - no big deal.
When I opened the bottom a lot of soty water came out. Hm… Could water have risen and poured in to the gasifier? I couldn’t belive it, but to be on the safe side I opened up one of my auger pipes on the dump. A cascade of water and char came out on the bed. Hm… Could water have risen up to the grate? I couldn’t belive it, but to be on te safe side I put my poker down to the grate and pulled it back up - it got wet. Hm…
I decided to light up and exercise it a bit do drive out the moisture. After blowing up and down for a while i shut the lid and started pulling through the nozzles. A strange bubbleling sound could be heard. Hm… Could water have risen up to my nozzles and flow down into my preheat void? I couldn’t belive it, but to be on the safe side I drilled a small hole into the bottom of the void. The gasifier started to pee.
I can’t belive how I managed to light up beeing wet up to the nozzles, but I knew this would require some major smoking. I drove out to a field where no one could see me and made smoke for a full hour before I got good enough gas to be able to drive home without gasoline.
Ooops… that sucks
A lot of “non believing” going on there. Your luck is sounding worse than mine. I still haven’t made piece with my truck since the auto show. Got a new clutch hydraulic cylinder and worked and worked to get it bled. Found the new plastic cast had a high pressure leak at the mold parting line. Ordered a replacement today. Maybe we will make piece tomorrow. Sorry about you problems. TomC
it probably wasn’t funny at the time but it sure made me chuckle a bit . put that one on the don’t do again list.
but glad to hear your all dried and running .
Question
Did you plug the hole you drilled in the preheat void?
Is this what you were talking about the other day when you said “it won’t be long”?
I made threads and put a bolt in (good to have if I ever have to drain it again 
)[quote=“don_mannes, post:278, topic:1928, full:true”]
Is this what you were talking about the other day when you said “it won’t be long”?
[/quote]
Exactly. But I hoped it would take longer than just a few days 
Hi JO,
sorry to hear about your accident, have you ever concidered joining the firefighters? 
sorry l had to 
I have a nother question. What is the aprox weight of your gasifier?