Wooden pistons BS or fact

Just for a bit of a laugh, I looked up if their had actually been any hacks where people had turned up some wooden pistons and used them for practical purposes in combustion engines. Much to my amazement Beech and Oak had been used during the second world war where supplies were short. The application where wood was used always had either an aluminum or lead flashing on the crown to dissipate the heat, and was used in low compression engines. yarchive.net...

I also came across a blog where it was at first considered BS, but turned out to be a factual account.www.bikechatforums.com...

a reply to: anonentity

I just learned something new. I would never have guessed you could do that. That’s really cool! Nice find you

There's an extremely tough slow growing woody plant here in Oz called Mulga which has been used for automotive applications in dire circumstances like no spare parts dealers for 100s or 1000s of miles. Uses like clutches and brake pads are somewhat common out there in the never never so making a piston out of it wouldn't be so much of a stretch of the imagination if the fine engineering tolerances could be achieved with 'bush tools'.

a reply to: Pilgrum


I probably think that if the wood was dry and then soaked in engine oil. It would be self lubricating and would probably not need rings, would still need a crown of some metal to dissipate the heat, I doubt whether the average guy could turn them up on a wood lathe, but a metal lathe would do the trick, bearing in mind wood would have more give when it went into the bore.

I dunno. Isn't it all about compression? Can wood achieve a high compression, being partially porous? Won't the wood change size as it dries from repeated explosions and heat? Wouldn't it need to be perfectly dry or else the moisture would shrink the wood and ruin the compression as it dried in use, and perfectly dry wouldn't it burn?

a reply to: hombero

Yes I'd think a metal crown of some sort would be needed to prevent the crown being reduced to carbon and eroding away. A normal metal piston is not perfectly round, being a slightly oval shape when cold that expands to a perfect round fit in the cylinder bore at operating temperature. Piston rings are required to maintain compression when the piston is cold so I'm not sure how the expansion characteristic of wood compares to that of metal but a piston without rings that fits perfectly in the bore when cold is almost certain to seize up when the temperature rises.

a reply to: hombero


When ignition occurs at top dead center, its really hot , then its pushed out through the exhaust valve, but when a new charge of gas and air comes in, its really cold, so it cools the top of the cylinder. So if the buildup of heat can be kept below the ignition point of the wood, then I guess the thing would probably work. It seems some one has done it.

a reply to: Pilgrum


Original cars didn't have piston rings, just a gas tight fit , like half a thou difference between the piston and bore size. If it was tighter it would seize. but wood is far more elastic than metal, and has more give. So if lubricated might go down the bore at the same size. Lignum is as strong as aluminum, so might not be the best choice, but it was used as bearings in submarines up until recently, so it proves some woods are pretty strong.

Imagine using a gassifier setup in a totally wood block an piston setup? Flintstones anyone?

a reply to: Disenchanted1


You might laugh but I read a report of a guy that made the whole engine of wood, the bores were old galvanized water pipe, it was low compression and ran on kerosene.
But this Russian guy made a good job of the pistons but didn't crown them with anything, he might have been a bit on the rough side.jalopnik.com...
However futhermore it appears original Seagulls had lignum pistons who would have guessed.saving-old-seagulls.co.uk...

a reply to: anonentity

This thread is awesome, that is all...

Wood and plant fiber are pretty amazing things. There's lots of things you can do with wood you wouldn't expect and there's a reason there's wood buildings a couple hundred years old that are still standing and looking better than some metal and concrete ones built in the last ten years.

This is pretty cool thanks for sharing.

a reply to: Pilgrum


I saw a guy on a U tube vid, cutting threads on a wood lathe, by hand, so I drilled and threaded a bit of oak at ten mm. Then screwed a metal bolt into it thinking that it would be easy to strip the thread , but no way it held just like as if it were metal.

It´s not about how "strong" wood could be or if it´s similar in strength to the common pistons like the ones made from aluminium and metal.

There are many other factors to consider. Heat resistance, oil resitance, shrinking factor (can´t remember the term) gliding coefficient and what not. If this is a composite material, well, then we are not talking about wood, since wood grows. It grows in fibers. A piece of wood is a dead tree carcass.

a reply to: verschickter

There are varieties of wood which actually do have the required properties in all of those categories to be workable.

As pistons especially without metal caps they definitely have a short lifespan, but they can and will work for a time.

Sorta like engineered obsolescence on steroids.

Edit to add: For me this is especially interesting because of my experiments with the Lloyd Tanner friction boiler. I'll be going through the links to see if I can pick up interesting or useful information that will help me in my pursuit of that project.

It's already got the wheels turning in my head on a few things though.

a reply to: roguetechie

I get that, I also saw the video, it ran on low compression for some seconds, sure it´s tuneable...But I foretell that the maintenance cost of one of those pistons burns through will eat that small marge that you gain by buying common ones.

The financial side will kill it, even if it´s more eco-friendly (I guess it is, since the supply chain would be way shorter for wood.

originally posted by: verschickter

shrinking factor (can´t remember the term) gliding coefficient and what not. .

co-efficient of expansion.


recently assisted in the engine rebuild of an Austin seven 1932. tiny engine but a pleasure to work on.
uk has zero piston procurement so a fresh thumper was sought from Australia.

with regards to the op I foresee an issue with the con rod to piston connector (grain split) unless a steel sleeve and pin are utilised even then not sure how long it would last.
without compression rings and oil rings I suspect a short lived unit due to contamination of the sump without a good seal.
I have handled lignum and would say that it is do-able with correct machining and piston rings in a dire scenario.

cool thread lol f

Perhaps ceramic crown would work.

Certain clays would do and might make a decent piston if having a hard wooden cradle.

a reply to: verschickter

Oh yeah you definitely wouldn't want to run it long term.

But say you're someone like me who has machine tools etc on hand and you need to make a vehicle run you back and forth to work until next payday when you can buy real parts.

It'd work just fine there.... Hrmmm now I'm thinking about brewing up a Laywood type 3d printer feedstock out of sawdust and high temperature engineering PET 3d printer filament / using some of the options available now to coat prints in thin metal cladding.

Totally useless and probably redundant but interesting nonetheless.

a reply to: roguetechie

Sure in your scenario it would make sense. You know the saying, provisional solution often last the longest. I fixed my 3D printer with a metal strip. The spanner that keeps tension on the toothed belt broke. Printed the broken part right away and it took me more than one year to replace it because the printer was running fine.

But I needed back those 1.5cm I lost on that axis so it became necessary. But until then, I got it CNC´d by someone, so I still have the PLA part flying around somewhere.