# Lifestyles & Discussion > Freedom Living >  One way to convert a 4 stroke, small engine to run on steam/compressed air

## noxagol

This video shows/explains one way to convert a small 4 stroke engine to run on compressed air, in this case at least. If you get an engine to run on compressed air, it will also run on steam. 

The key is valve timing. A 4 stroke won't work right out of the box because the intake stroke becomes the power stroke, and what was the compression stroke becomes a jam since it tries to compress the steam. What is done in this video is the camshaft is modified to turn it into a 2 stroke engine. I will let the video explain the rest and am now giddy to try this on my dads defunct 5.5hp tiller engine.

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## speciallyblend

look forward to watching this!!

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## noxagol

I think im going to attempt this myself tomorrow. I think I will make a video of it.

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## ChickenHawk

This engine won't work. It could be modified to work but it won't be very efficient.

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## Live_Free_Or_Die

once you create a working cam with welding/grinding...

pour one:

http://backyardmetalcasting.com/

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## noxagol

> once you create a working cam with welding/grinding...
> 
> pour one:
> 
> http://backyardmetalcasting.com/


The only problem with that, it would require machining I can't do right now since I don't have a lathe and it would have to be cast iron, which is a lot more difficult to cast, and has to age for like 6 months before it can be readily machined. Aluminum is too soft and would wear out really fast.

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## noxagol

> This engine won't work. It could be modified to work but it won't be very efficient.


Why won't it work?

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## ChickenHawk

> Why won't it work?


It would require a large amount of highly compressed air to have any power and run time. If you injected the highly compressed air into the intake manifold as he proposes it would force the intake valve off its seat and flood the engine with compressed air forcing the piston to stay at BDC (bottom dead center). 

If you modified it, as he suggests, to inject timed pulses of compressed air into the spark plug hole that should work but the energy required to compress the air and the losses in the engine itself would combine and probably make the engine far less efficient then just running it on gas. I'm speculating a bit on this point because I'm not an expert on thermodynamics.

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## noxagol

Hmm, I hadn't thought of the valve and the pressure on it. I would use it as steam engine anyways. Well, I guess we will find out how well it works once I get around to doing it myself.

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## noxagol



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## Anti Federalist

> Hmm, I hadn't thought of the valve and the pressure on it. I would use it as steam engine anyways. Well, I guess we will find out how well it works once I get around to doing it myself.


I think the way to do it would be to change the cam timing to turn it into a two stroke cycle, and introduce the steam/air, through the spark plug orifice.

A two stroke cycle with a flywheel would work.

Starting at TDC with both valves closed, steam expands and pushes the piston down.

Bottom of power stroke, cam timing to open *both* valves while steam is still being introduced into cylinder (lots of waste here, that would be solved by rigging a slide valve/connecting rod/eccentric off the crankshaft to stop steam flow while the piston was on it's up or "exhaust" stroke)

Piston travels to TDC and process repeats.

Or, you could just modify the camshaft to open the exhaust valve every stroke instead of every other stroke and leave the intake valve closed permanently.

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## pcosmar

I have an old 2 stroke, 2 cylinder snowmobile engine in my barn I am going to fool around with
Just need to find a pair of valves (solenoid).

Might have a little generator motor.

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## noxagol

> I think the way to do it would be to change the cam timing to turn it into a two stroke cycle, and introduce the steam/air, through the spark plug orifice.
> 
> A two stroke cycle with a flywheel would work.
> 
> Starting at TDC with both valves closed, steam expands and pushes the piston down.
> 
> Bottom of power stroke, cam timing to open *both* valves while steam is still being introduced into cylinder (lots of waste here, that would be solved by rigging a slide valve/connecting rod/eccentric off the crankshaft to stop steam flow while the piston was on it's up or "exhaust" stroke)
> 
> Piston travels to TDC and process repeats.
> ...


That is what some people do. They just grind the lobe off of the intake cam and leave it sit closed then make a valve and timing system for intake through the spark plug, which is optimal. From what I've read, you can go up to about 30 psi on stock springs before the pressure forces the intake valve open. You could go to stronger springs for the intake valve, only costs about 30 bucks for them. Adding lobes to the cam shaft and using the regular intake port would be the easiest way of converting. 

I will try both, starting with adding lobes first. Then, I will just remove the lifter for the intake valve so I can keep the cam unchanged but the intake valve will remain shut. Then add intake to the spark plug. I might scrounge up another cam shaft and have it so that both intake and exhaust valves open on exhaust strokes. That would have less power loss during exhaust since you almost double the amount area steam can exit through which allows it to evacuate easier saving more energy. For that, all you would do is grind off stock intake lobes and add lobes to match the exhaust.

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## osan

> Why won't it work?


The salient point is not whether it would work, but that the goal is not sound.  If you have the means to compress the air, you probably have the means to run, say, a generator as well without adding another element to the works.  Compressed air is a manufactured energy source.  If you can manufacture that, you can probably manufacture electricity.  One wants the chain of transformation from fuel to power to be as short and simple as possible.  The more hand-offs you have between start and end, the less efficiency.

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## acptulsa

> If you modified it, as he suggests, to inject timed pulses of compressed air into the spark plug hole that should work but the energy required to compress the air and the losses in the engine itself would combine and probably make the engine far less efficient then just running it on gas.


No one addressed this.  You're right, but people here are looking for ways to make steam engines because they want to run solid fuel.  Got a fuel injector that can insert wood chips?

The thing about converting even two cycle engines to steam is it eliminates the thing that kept steam so efficient--the fact that it's a single cycle engine.  None of these engines are designed to hold pressure on both sides of the piston.  An old piston water pump (if you can find one), on the other hand might be just the thing.  The valves should be easier to work with, too...

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## noxagol

A compressed air engine can run on steam. The advantage of steam engine is that you just need a boiler with water and ANY fuel source to power it. That is why this is relevant.

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## buenijo

> No one addressed this.  You're right, but people here are looking for ways to make steam engines because they want to run solid fuel.  Got a fuel injector that can insert wood chips?
> 
> The thing about converting even two cycle engines to steam is it eliminates the thing that kept steam so efficient--the fact that it's a single cycle engine.  None of these engines are designed to hold pressure on both sides of the piston.  An old piston water pump (if you can find one), on the other hand might be just the thing.  The valves should be easier to work with, too...


Use a wood gasifier to run an internal combustion engine. Old technology guys.

All Power Labs main web site: www.gekgasifier.com
All Power Labs YouTube page: http://www.youtube.com/user/allpowerlabs#p/u

Victory Gas Works main web site: www.victorygasworks.com
Victory Gas Works YouTube page: http://www.youtube.com/user/VictoryG...s?blend=2&ob=1

STEAM POWER: Steam power can be ideal under certain conditions where the heat in the exhaust steam is put to full use. Outside of this setting, old steam technology is too inefficient to be be practical. A typical steam system will consume three times as much wood fuel to produce the same work as compared to a wood gasifier used to power an internal combustion engine.

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## buenijo

> The salient point is not whether it would work, but that the goal is not sound.  If you have the means to compress the air, you probably have the means to run, say, a generator as well without adding another element to the works.  Compressed air is a manufactured energy source.  If you can manufacture that, you can probably manufacture electricity.  One wants the chain of transformation from fuel to power to be as short and simple as possible.  The more hand-offs you have between start and end, the less efficiency.


Ah, a voice of reason. 

My advice to anyone who is serious about energy independence is to study:
(1) wood gasification for powering internal combustion engines, and
(2) small scale steam power

An ideal off grid home could make use of both technologies. An ultra-reliable low power steam system can be operated almost continually to provide basic electricity, battery conditioning, water distillation, fuel drying, space heating, and even air conditioning using an adsorption chiller. A wood gasifier can be operated intermittently where high power is required (i.e. charging a large battery bank, powering a tractor, etc.).

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## Anti Federalist

> The thing about converting even two cycle engines to steam is it eliminates the thing that kept steam so efficient--the fact that it's a single cycle engine.  None of these engines are designed to hold pressure on both sides of the piston.  An old piston water pump (if you can find one), on the other hand might be just the thing.  The valves should be easier to work with, too...


Yes, that.

No matter how you slice it, converting any IC engine to steam will result in a wildly inefficient engine since you cannot introduce steam on the back side of the piston.

Good information to have in an extreme pinch, but you'd be much better off either restoring an existing single expansion (or double or triple) like these folks did here,

http://www.ronpaulforums.com/showthr...d-power-system

or building one new from scratch.

It can be done you know, with phenomenal results.

This 100 mph locomotive was newly constructed from scratch, her first run was 2008.

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## buenijo

Old steam systems are generally not very efficient. But don't confuse thermal efficiency with mechanical efficiency. A double acting engine will have a higher mechanical efficiency than a single acting engine (all else equal). This can make a big difference in net efficiency when the thermal efficiency of the system is low (like old steam systems tend to be... hence, old steam engines tend to be double acting). 

An internal combustion engine that is converted to steam is going to likely see very low efficiency primarily due to thermal losses. IC engines are designed to radiate heat. Steam engines are designed to retain heat. Some internal combustion engines could be converted to steam power with good results, but definitely take care to insulate the hell out of them. For example, a three cylinder stationary Diesel engine in Australia was converted to steam provided by a solar concentrator. It saw a thermal efficiency of 22%. BTW, it was a single acting engine.

http://www.rossen.ch/solar/wcengine.html

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