David Ayers' Project

We’ve yard saled up the welders, and the torches, and are a mask, and a tank of argon from starting on the? (Once we get our welding licks down). What we think we might be starting on, is a one ton Suburban with 4wd and a 454. The plan is to bob the Suburban into sort of a Avalanche, with a short stakebed, where the rest of the Suburban used to be. These rigs are laying all around for next to nothing. We might spend extra on a good one, or pick up a beater and stroke it out to a 496. Probably we will stroke it sooner or later, anyway. I’m just curious as to why big block Chevys haven’t caught on with this crowd, and hoping there’s not a good reason. And wondering why I don’t hear undersquare engines mentioned here? A long stroke and high compression seem like a natural to me. Is there something I’m missing? So, I’m going on the mountain to pick huckleberries, and hope I find a good answer, when I get home.

Makes prefect sense to me. That sounds like a good combo it sould be a torque monster. It seems to me that with a slower burning fuel such as wood gas the longer the stroke the better and more power one would get out of it. High torque at low (slower) RPMs sounds like the best canidate for a wood gas engine. Maybe some of the experts here will chim in and correct me if am wrong here.

i’ll be trying this unit on a 305 chev… can’t see why it won’t work.

Hi Dave
I think the 454 would be a good choice problem around here they are like gold
all the street rodder’s want them. My cuz has an old dragster engine i think it’s a keith black 591 cu in alum block and heads but some thing tells me he won’t go for that LOL
I went to an 1800 rpm gen set and i thing works way better on wood gas then the 3600 rpm one i first tried
good luck

Hey DavidA.
454’s have been done; in the progress to being done. Look at Dutch Johns running 74 project here and the separate discussion on the fellow building a Chevy for 7500 foot high altitude. This second may only be in the Builders Discussion section.
DavidA and SheldonG,
Arvid is correct start a separate topic lines on both big block Chevy discussion and undersquare versus oversquare engines for woodgasing and I promise I would participate in the second and with historical and current use try and convince you oversquare will hands down beat out the other on woodgas anytime, anywhere.
Ha! Ha! TomM. YOU want to be fuel sourcing and prepping for one of these fuel hog monsters? You know this well now man. Roger on the highly loaded, lower RPM for woodgasing IC’s. 3600 RPM is doable OK but at the cost of a nervous breakdown.

Steve Unruh

Moved to a new topic… carry on.

Thanks Chris, I love this site. I learn something new everyday. So which is better longer stroke or bigger bore for wood gas engines?

only substitute for cubic inches is more cubic inches… I have heard of talk of over bore and under bore… I think the out come of that talk was over bore was better but i can’t seem to remember why… I’ll ponder it some and see if i can remember

hi Arvid and all
I agree if not worried about fuel comsumption and engine life cu inches are cu inches.
When I was young and dumber then i am now if thats possible haha I had a semi with a 250 cummins in it they were slow so i had the bright idea that i would put a 400 hp gas engine in it and set the road on fire TEE HEE Besides not being able to start a load very good i soon realized that the rpm needed to get the 400 HP would only yeald about 500 mile engine life I knew there was a reason my daddy called me sunshine LOL Soon i went back to the smoking cummins and life went on
I don’t know that much about wood gas just my little gen set seemed better when i went to an 1800 rpm set up ofcoarse there were probably other factors the figured in that i may have missed
either case i can’t wait to get my nissan on wood
have fun Man I like this site

Hi guys on the IC engine configuration for wood gas. Well anything can work as shown by the over 100 years useage with anything possible from flathead/valve in block to overhead cams to blown 2 cycle German industrial diesels.
What would be best today? Comparatively oversized for the power, overhead valve with a bigger bore to stroke but still a long rod engine with the best breathing possible.
The combustible wood gases molecules are simple and easily combusted. Fast burn H2 blended with slow burn CO, both modified by the presence of min 40% N2 and 8-12% CO2 and throw in a dash of 1-4% CH4 methane.

Other factors for the engine envelope like mixture flame front burning speeds and cylinder filling with air (and fuel gases with propane, methane and woodgas) are just as important.
Compression ratios, ignition timing and combution chamber/piston head shaping can change the flame front speed as dramatically as the fuel base type.

Gasoline molecules are complex and need comparatively more in cylinder time to be completely broken down and combusted. VW/AUDI’s long stroke 5 valve gasoline engines as the modern extreme to this for efficincy.
Diesel and heavy fuel oils are the most difficult to completely combust of all and need the longest in cylinder residence time. 178 RPM ship very big slow long stroked engines as the extreme for heavy fuel IC engine efficency.

This is why the directions each dedicated fuel type IC engines evolve into. And the more they are power to weight, and power to displacement developed for a specific a fuel the harder to run on anything else.

Practical terms of todays V-8 American engines for woodgas:
The Ford last genrations of SEFI FI 302, 351 and 460’s
Chysler/Dodge last generation of Magnum Port SEFI 318, 360 and the pushrod valve Magnum V-10.
Chevy the last port fuel injected Vortex actual small block 350 and 454’s. These last port injected factory 454’s have amazing manifolding you get for free with the engine.
I think these will woodgas beat out anything expensive, exotic as a daily (YOU SOURCE, PREP AND CUT THE FUEL) user than anything hot-rodded together or the later factory OHC V-8 factory engines. Maybe with the exception of the Gen III and some of the GEN IV LS still pushrod valve Chevy V-8’s. Real interested to see when someone woodgases one of these.

Steve Unruh


the above i couldnt have said any better, and learned a thing or two reading it

the summation of all my research leads me to believe modifications to your intended engine that you would do for increasing torque or overall efficiency seem to be in favor of a more reliable stronger well behaved woodgas engine

things like porting, since this fuel is a “gas” like air, getting the engine to breath, cross sectional area is important, larger valves and a free flowing port with some swirl, the swirl can improve exhaust gas exiting the cylinder aswell as complete efficient combustion
raised compression ratio is one of the best ways to increase torque/hp numbers fuel knocking is the limit here, along with heads material ally or steel
cam, id say mild to rv oriented, i think the poor vacuum characteristics of big cam behavior kill its gasifier pull until the engine is screaming, IF the woodgas will even spin it that fast…
hardened valve seats, a must for dry fuels
id say long stroke engines give better results since the stroke determines the mechanical advantage on the crankshaft, larger stroke is bigger torque
fuel injection, for reasons listed in the premium side aswell as ease of fuel control on off bifuel
i would say forced induction aswell since this pulls the gasifier harder, sean shared his experiences with me and the boost can kill the gasifier but i believe if the boost was limited to 5-10 psi a stout gasifier would hold up
oil quality/cleaning/changing is important, this leads me to consider oil centerfuge for my application
computer system and intake material, intake dual plane or single plane, distributor or coil packs, timing, exhaust system,
engines are air pumps
many other things can vary results but i tried to touch on the things im focusing my 460 efi build on

I guess, I was thanking that any wood gas engine would run based on what I’ve be reading here below 3000 RPMs 90% of the time. So if one could make maximum H.P. and Torque below that threshold or somewhere close then it seems like that would make a good wood gas engine. But like ya’ll said there are a lot of varibles to thank about.

Fellows don’t be disappointed - again, almost ANY IC engine can be made to run on woodgas.
Kinnda the trend of this topic has been what configuration would be best. And as TomM. pointed out what engine configuration will LIVE a long productive life and not just be a 500 hour disappointment.
This last relates to piston speed versus connecting rod length which is related to it’s working/pressure angle and what this does to piston side thrust.
The OEM’s know this stuff to a fine level. They know when they step outside of certain hard experienced learned parameters on these factors, yes, they may have the power but then an engine only living in real life for under 100,000 miles or a 2000 hour service life.
They knew the 400 cid small block Ford and Chevy factory motors with there long strokes short connecting rod length ratios would have the pistion/ring/cyclinder wall side pressure and bearing loading to not be 100K plus long lived. Put them out due to marketing sales pressure. Opposite this this is the reason 366 GM, 345 IHC and the Ford equivalent were set up to have such long service lives in school busses, service and rental fleet trucks. But these NOT anywhere the best to woodgas with having restricted breathing for the best gasoline fuel atomization. Fleets wanted long service life with the best fuel economies possible.
The 178 to 300 RPM ship engines have a yards/meters long stoke and long, long rods. The pistons speeds to cover this amount of distance is fast, fast, fast the same as a V-8 engine screamer set up. The combustion flame front has to be fast enough to exert a usable working pressure on these fast moving pistons. FAST piston speed engines again not near the best to woodgas with. CO fuel gas component is too slow and still burning when the crankshaft degrees turning is now driving the piston back up. Burn pressure energy now fighting rolling momentum energy. A waste resulting in heat and severe pressure and wear on the parts.
Good race IC engine builders know this stuff too. Their goal is to take all of the manufacturers built in longevity factors out and trade for power with just enough durability built in to last the race or series. Slow and durable does not win races. Over the edge set ups does not finish the race at all.
All of these same factors applies to 4 and 6 cylinders IC engines too. Many NON-Valve INTERFERENCE SEFI/Port FI engines would be excellent to woodgas fuel. Dual overhead cam piston/valve cruncher engines NOT. Exceptions always of course.

Steve Unruh

Thanks Steve, I always look forward to learning something from your posts. And I always do. I have a 536 ci Ford engine in a Fire truck that I plan on making a flat bed farm truck out of for hauling hay and feed on. I hope to work on it over the winter. And make it a wood gas inhaler.