With the new reduction opening , you most surely have add to the turn down ratio.
Bob
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Bob, I was thinking 5" at first, but chickened after realising that would mean a 50% csa increase. Also, I think my grate is close enough I will brobably not benefit from it. The by-pass will probably be tighter than the actual restriction.
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5" would be awfully brave for a 2.3L 
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It will be interesting to hear if you notice any difference, in force or outgoing temperature, I cleaned mine yesterday, and see that my restriction has become smaller? Also wondering if 2 "is too little up to the engine.
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Did it shrink? How is that possible? Ash buildup?
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No, it apparently happens with some materials, the height and inner diameter change, but the outer diameter is the same. They got equal in the tests in the 60’s.
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Wrought iron JanA?
The layers in wrought iron often heat and corrosion separate causing dimensional growth.
And I have too seen this on cast iron that has continuous direct contact to hot glowing wood charcoal. The added absorbed carbon molecules, maybe.
Only ~56mm? seems very small. Even for 700-1000cc generator engines I am unhappy below 75mm. Evolved down chars bits passing for my woods like a minimum of 100mm the best. Also depend on the amount of mineral ash in the wood having to pass too.
Regards
Steve Unruh
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2" is the minum you should have for a 5.2 L engine for incoming gas line. I have proved it by adding a
1 1/2" controlable extra gas line on my truck. When opening, it makes a noticeable difference at high end speeds with extra gases being added to the engine. I know this is after the restiction opening but it is still a restiction that limits the flow.
Bob
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BobMac remember that downstream gasses flow are relatively cold and been made dense.
Gas flows through the hearth restriction are super hot heated expanded.
Plus that restriction’s Circular-Surface-Area must also pass devolved char particles and freed up mineral ash too.
It must be bigger.
S.U.
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Ok so help me understand what you guys mean when you say mineral ash? Minerals that are contained in the wood and not burned up? And if that is the case is it a temperature thing, where a not hot enough fire can not consume them to make more fuel, is it a tree/wood species thing where each has a higher or lower mineral content that has to be dealt with in the hearth? and what harm is there to let it pass through the restriction so to speak?
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I think it was steel from a hydraulic cylinder in restriction, if you look at the picture it shows how restriction decreased, driving time at the top and decrease in restriction on the line below.
Thanks Bob, I’ve suspected this for a long time.
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If something never give you trouble its too strong or or too many resources are allocated to keeping the plant running.
The danger is you can get into the mind set that something needs to only last as long as the warranty or place is so poorly staffed people go crazy from the stress and start to quit.
To some extent there is a point where this can make things lighter and cheaper without significantly compromising value…
People go to university to learn how to design things and processes that have a predictable life expectancy.
Yes it flies in the face of conventional logic to make things as strong and reliable as possible, but someone proved it was the most cost effective way to run a consumer based society.
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Marcus, yes the mineral ash is uptaked from the ground and becomes part of the cells walls. Burn away the hydrogens and carbons and the mineral ash will remain. A small amount I suppose is by the intense temperatures is vaporized (not fuel capable, but catalyst capable then).
All of cell walls ash freed up above the restriction; yes, must be passed down through. Ash with a lower melting temperatures will melt and fuse together. Clogging clinkers!
S.U.
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That is why I can heat the house with Douglas fir wood for 2 to 3 weeks before ash removal.
With alder or cottonwood only about a week.
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Or melted ash; as J.O. speculated, fuse layering at the restriction opening surfaces slowly building up? Narrowing the opening?
Chip, chip. Scrape, scrape to learn why.
S.U.
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Yes I agree Steve. And I am using a 7 1/4" restection opening on my 5.2 L engine. So it seems to me 2" would be a little small for Jan restection opening on his engine because of what you have stated.
Bob
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I’m pretty sure Jan was talking about his single 2" pvc up to the motor compartment - wether it was enough or not for his 4.3l V6. Also, our 2" pvc is only 1"7/8 ID. Some brands even narrower.
Even the OD is smaller, 50 mm, which is slightly less than 2". If I remember right US 2" pvc is 53mm OD or even more?
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For NPT sized pipes, the nominal value is for the inside diameter. A 3" PVC pipe is usually 3.5" OD. Very annoying with the Fernco rubber couplers when you use anything but PVC pipe because it’s a Nominal value.
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Cody, if this was a shallow heart, Imbertish gasifier, I would probably have kept the 4" restriction. It seems more depth to the charbed justifies a slightly larger restriction. Dwell time for gasses to convert, instead of a super hot instant reaction.
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Okay then yes the 2" gas line pipe to the motor compartment is big enough if I can run on a 2" pipe. The reason I went with more is for climbing hills and top end speed. On my auto mixer the opening is only 1 7/8" ID and not 2" ID. Adding the extra manual intake gas line pipe made a big differance.
JO do you run with a 1 7/8" intake gas line pipe or is it smaller ID on yours?
I know the math will sometimes say one thing but in actuallity it doesn’t work depending on drag inside a pipe by making turns and such like soot build up.
Bob
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