Nozzel size for engine CU IN

I have just spent a few hours on the forestry forum reading up on a MEN build.
The link: Wood burning truck! in Alternative methods and solutions

I didn’t realize that nozzle size played such an important role but in hind sight it makes sense. The MEN build in the link provided was as he admits a little overkill and his engine was a 302 at 300 cu in. My V8 is around 215 cu in so would I be right in assuming nozzle size would be about the same?

He provides the following info from MEN:
Then, to solve the bridging problem, we oriented the
outlet tips of the manifold pipes so that the “odd” eight point
straight upward …and the remaining “even” nozzles aim inward,
toward the center of the hearth opening (see the illustration). The
benefits of this arrangement are twofold: The horizontal jets provide
combustion air for oxidation at the entrance level …while the
vertical outlets reduce the size of the chunks of wood about to enter
the hearth by cutting away at them like miniature torches, thus
eliminating the possibility of having a “logjam” block the flow of
fresh fuel.
the 250-cubic-inch powerplant used in our Chevrolet truck
(which turns at about 2,800 revolutions per minute at 55 MPH, the
speed at which most of its mileage is logged) requires an overall
nozzle area of 1.237" (horizontals 0.36", and verticals 0.26" in
diameter) …a nozzle-to-hearth separation of 5-1/2" …and a hearth
restriction width of about 5-1/4". (Generally, the total nozzle area
should be 5 to 10% of the overall hearth area.) To size the openings
in the nozzles, we simply drilled holes of the proper diameter
through 16 pipe caps, and threaded them over the feed-tube outlets

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Tim, I’m using MEN style nozzles design for a 2.2L i4 engine that I’m building a gasifier for. I am using 10 nozzles in the alternating fashion just as you described. My nozzle hole size is 1/8". The advantage of plumbing parts and using pipe caps or plugs is you can change them out if the orifice size is too big or small.

Edit: I misremembered, my nozzle jet size is 1/4"


Thanks Cody
Is that 5 of each alternating making ten total? Or 20 total?

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5 of each alternating, 10 total. I used 90 degree iron street elbows in the 3/8" NPT size. For your V8 I’d suggest to use the 1/2" NPT size.

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