Author Topic: Need help to convert 4-stroke engine to run on compressed air  (Read 825 times)

citengr

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Need help to convert 4-stroke engine to run on compressed air
« on: November 25, 2015, 03:40:42 AM »
Hi:

I am trying to convert a Ryobi X430 4-stroke single cylinder engine to run on compressed air.  I asked a welder to help me to change the intake and exhaust cams so that the valves would open on every down stroke instead of every other down stroke.  Unfortunately, he took the timing belt out, and I have not quite figured out the exact timing position to put the belt back.

I connected the compressed air to the spark plug port, and the piston would go down powerfully.  However, it would not come back up.  Any suggestion on what I should do?

Please ignore this message after Dec 2015.

Thanks

smallengineshop

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Re: Need help to convert 4-stroke engine to run on compressed air
« Reply #1 on: November 25, 2015, 04:50:26 PM »
My guess is you need to increase the force created by the air blast, and increase the mass of the flywheel connected to the crankshaft to give the crankshaft more momentum. Have you ever seen the massive flywheels used on oil drill rig gas engine's? These engines run at very low rpm and require a massive flywheel to create the momentum needed to rotate the crankshaft between power strokes. Linear momentum is a product of mass and velocity (p=mv). Since were dealing with a rotating object (crankshaft/flywheel) we want angular momentum, which is a product of moment of inertia and angular velocity (L=lw). You can find examples all over the internet for determining linear and angular momentum. Here is a vid:

<a href="https://www.youtube.com/v/smCQ2g9L7PU" target="_blank" class="new_win">https://www.youtube.com/v/smCQ2g9L7PU</a>
« Last Edit: November 25, 2015, 07:04:52 PM by smallengineshop »
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The Small Engine Shop

Re: Need help to convert 4-stroke engine to run on compressed air
« Reply #1 on: November 25, 2015, 04:50:26 PM »