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Anyone have blueprints or designs for a practical, full-size steam engine ? Answered

A groups of friends and I (15 years old) are looking to re-create a steam engine to power a survey (we're thinking something along the lines of a steam-punk carriage powered by this steam engine)  we are designing. It does not have to be fast or very complex, just something to propel our vehicle forward. It must, though, be large enough to push at least three hundred pounds and operate for a good amount of time without needing to be refueled or tended to. After searching Instructables, I have found a ton of good steam engines, but they're all mini or meant for demonstrations. We need plans or ideas for a real, full-scale, functioning engine.

Any advice, plans, or ideas someone has would be greatly appreciated!!!!

Thank you all for your help,



Have you guys got good shop skills ? The boiler is probably the scary part: It MUST be properly designed and certified - even model engineers get their boilers hydraulically tested.

What you are looking for ideally would be a double(or triple) expansion marine engine. Not many engines were built for road duty !


Check out greensteamengine.com Green is the designers name. The plans for a two cylinder engine cost about $40 and the parts to build it come from your local hardware store. Cost is about $100. It is a low pressure steam engine and the boiler can be a pressure cooker. This unit should be powerful enough to run a small cart. It will operate a 5kw generator. If you build one I would like to see your progress on Instructables, especially if your teacher helps and makes suggestions or modifications. I am thinking about getting the plans for myself. I am wanting a backup generator for off grid power that does not rely on gasoline or propane. 


Hey guys,

I've got ideas for you. You need to find a BIG two cycle engine, the bigger the better. The neat thing about these is that steam engines are also two cycle engines!!! You won't have to worry about "building" the engine. You just need to convert it to steam/air.

The steam/air could be injected into the intake( where the carb. is mounted). This would be a single acting engine. Or, you could inject the steam at the spark plug port; you would have to seal off the intake port with a relatively heavy plate and gasket. The pressure would be released via the exhaust port as usual. This is about the cheapest way to go. Short of actually building the system; that I have been able to find. Yes, before you ask; I have been thinking about this myself for a long time.

I wish you good fortune and hope you will let me know if I can help you with any other ideas. Waiting to see what your group comes up with.

Building an engine powerful enough and safe enough to drive a carriage like that is a major undertaking.

It will cost thousands of dollars in materials and tools, plus months, possibly years of work.

But, there's nothing stopping you trying if you *really* want to give it a go:




might be able to squeak it under 500 bucks if prebuilt components(i've looked, they're available and cheap) can be found.

Actually, we're getting in touch with our shop teacher to go over whether it's possible to try to make one with his supervision. The more we look into it, the more "explosive" the engine is becoming....

Thanks guys! We'll make sure to do a lot more research into this, try your ideas, but in the end it looks like faking it will probably be the way to go. Thanks to everyone for their answers!

Prohibitively-expensive I think, big means high-pressure and paperwork - fake it instead.


What country are you in?  IN the US any boiler large enough to power  your surrey will have to be inspected, certifies and may have to be operated by a certified boiler operator.

Google "steam engine forum" and join a few to get really good knowledgeable answers to your questions.

It's doable.  Pre made castings for the cylinders etc. are available.  The problem is that steam engines take ALOT of steam to make their power and the higher pressure the more efficient they are.  The higher the pressure the more dangerous (deadly) they become.  Hence the requirements that it is a safe design and run by someone who knows what they are doing.