To raise compression you can lap the head and block mating surfaces and install without a gasket. Lap head and block on plate glass with valve grinding compound and use a tiny amount of gasket sealer between when bolting together. I found this suggestion from a guy who has done this on many engines without failure.
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We have done that a lot to our 50ccm 2 stroke mopeds. On the moped l converted to charcoal l ground the head down about 2mm, wich gives a theoretical compression ratio of 13.5/1. It run great on chargas.
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Hi Kristijan, on your 2 stroke how did you oil the engine running on charcoal gases? Do 2 stroke 50ccm mopeds engines have a crank case to hold oil for lubrication?
Also did you have to advance the timing?
Bob
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I have also used something like this:
An inline small fuel filter might work or a chainsaw fuel filter.
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Nope, no crankcase oil. The mopeds run on premix. Some more modern 2 stroke engines use oil injection via small crankshaft powered pump so l replicated that. I extended the shaft on the engine (where the magneto was) and fited on a scuter oilpump. It wuld meter oil in the gas/air stream. But that wasnt the most bulletproof solition, its easyest to just drip oil in.
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Pictures of the lubrication system
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You worked on it in your kitchen?? TomC
Oh god no 
thats a room we use as a pantry, wine cellar and buchering. I moved the moped in at the time for it to dry before painting.
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What’s wrong with working on engines in the kitchen? I rebuilt a Toyota engine in our living room. Great conversation piece. That was nearly 40 years ago in our first apartment as a young married couple. I don’t think my Cathy would go for that today.
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You answered your question. Many of us have done such things but usually before our Mrs.'s came into being.TomC
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Hi TerryL.
I did try on some self-made intake “lowest restiction flow” Y intake mixers to do anti-reversion steps. Tryed length tuning too. I think it did work . . . but . . .
just like 2-stroke exhuast tuning then made the engine very, very RPM power band tweeky, sensitive.
After doing some actual old 1920’s thru early 1940’s Onan electrical generator history reading evolutions then I finally realized just why they later in the 1950-80 simply went to a two cylinder opposed engine design for their military/industrial units. No more 3600 rpm, versus 60 cycles electrical harmonics voltage flickering.
I moved onto to V-twin aircooled and then virtually all of the problems went a way. These start as 4xx cc and go up to ~1000 cc in industrial lawn mower generator sizes.
Ben Peterson moved on up to the inline watercooled small natural gas Kubota engines for his pumpable H in his CHP projects and all of the intake pulsation and power pulse flikering went away too. 532?-972cc engines
I kinnda’ think this is why he made his book-system as large as it is for an engine required best-use basement that would restrict out single cylinder gasifing problems.
The easiest problems to solve are those you just step past, and around and move forward past.
Regards
tree-farmer Steve unruh
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OTC engines ( Onan style Opposed twins ) deliver less flicker, smoother less vibration,
Downside is almost almost all are flat heads and the fuel burn rate is high.
They were designed to be compact and reliable.
If you find a J series stationary plant you have something with more compression better breathing and lower fuel burn.
Here is a very nice JC 15 kw unit.
This shares a lot of parts and castings with the DJc 12.5 kw diesel varient.
I think its possible to do a simplified wood gas conversion of these engines,
Be prepared to pay.
Not cheap…
Guys who own them talk about them like they are their children.
Considering costs Onans are expensive.
There are alternatives.
Here is a slide show from 1959 introducing the Slant 6 one of the best inline sixes I think ever found its way into a north America car or light truck.
Inline six for smooth low vibration running, nice long rods for light side loading, wedge heads, easy to service.
I think a fellow could easily make a very good wood gas conversion of this or an industrial/marine version.
I think it could reliably make 30 hp on wood gas and generate the desired 15 kw at 1800 rpm most would want for home ( plus the heat from the cooling system never forget that )
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I had a standard shift Dodge (Dart, I believe) with this engine. It had 155,000 miles. I put 50,000 hard miles
on it and had no problem selling it at 205,000 miles. The Dart had a tough steel body, like a little tank!
One of the best little cars I have ever owned.
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This machine looks so efficient. It’s going to be my next project. I have watched several YouTube videos about it. Thanks for all your work and sharing, Gary. This is the kind of project, along with a charcoal maker, that I would recommend to a friend. I’d like to learn all I can about it.
Current state of the charcoal retort. I put the layer of rock wool in between the barrels rather than on the outside.
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What a butyfull retort! I can hear the charcoal ringing.
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Yes, beautiful set up!
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How did you get that wool between the barrels ,poke it from the top with a stick?
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I love your build quality i can just see from your work you are a craftsman at what you do , it puts my held together with string and sticky tape to shame .
I built the same same retort this winter for cleaning up all the fallen branches and leaf litter off the ground , but had the insulation on the out side and its now destroyed from rain and tipping the drum over , but the one thing i did that i consider was a better way was at the bottom instead of a 90 deg bend out the bottom of the drum ,i went straight down and also took the gas pipe down as well , i then sat the drum on a low stand and lit a fire underneath instead of the rocket type pipe that needs constant feeding , the burn chamber under the drum could accept a lot of uneven sized twigs leaves and anything else that burns .
Well done on your work first class !
Dave
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I 100% agree with your engine assessment opinions Mr Wallace.
The flathead opposed Onans and Briggs ARE fuel hogs with very limited compression increase possibilities. Poor, torturous gas flow pathways. Huge HC’s emissions making internal quencing surfaces.
However there was once a very good set youtubes of an inland central California fellow’s woodgas DIY system conversion build up of a cast iron flathead B&S generator unit. He was happy with it.
And on the old Lister Engine Forum there was a guy with a Latin screen name converted a Dodge Slant 6 in his basement with boosted compression and timing changes to 1800 RPM run on street natural gas easily able to quietly, smoothly, generate a solid verifiable live 30 kW electrical if/as he needed AND give him a lot of pumped hot water H for his home heating.
His next steps was to farm for exhaust water heating. His engine radiator, and engine external heat warming his basement to rise up into the undersides of the occupied floors above. Toasty warm feet for the family.
He used to laugh at many of the 950 pound CS Lister single cylinder guys struggling with their hop-away and ground shaking problems. I think they finally banned him off?
GregC,
I did intentionally buy a new 2800 watt Yamaha Inverter-Genrator unit as the smallest I felt I could reliably woodgas fuel off of my own personal Victory hearth gasifier. The engine is a Yamaha 172cc single cylinder four stroke. This operates variably between 2800-4200 rpm depending on electrical loading. The internal inverter converting the wild three-phase generated AC (~150-300 vac) to stable regulated 60 hertz, single phase,115 VAC output.
My gasifier is the original #1 prototype smaller internal sized hearth versus the enlarged production Victory hearth models. I have very much the same internal volumes and spacing as your biult up Ben Book system. And I have lots, and lots of exprieneces with this particular unit.
You CAN do this with yours too.
Just have to wood inputs fuel and operate for the low gasifer heat/volume loading as I had described.
A multi-cylinder engine, hard drawing gasifier experience is easy. Easy to get heated up and gasifing well. (Easy to heats overload to too hot, too; with big engines demanding!)
Contrary to wishes&hopes: it is the little ones are HARD on every step of it.
tree-farmer Steve unruh
Regards
tree-farmer Steve unruh
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