I need to maximize my RPMs in a single cylinder flywheel

[raclemai]

I am working on a flywheel single-cylinder engine powered by a 40 psi air compressor. My task is to achieve as many RPMs as I can. I have already bored two exhaust ports in the frame as shown in the pictures attached. I've done some 600grit sanding on points of contact, am using lubricant prior to air compressor connection, and am planning on shortening the stroke of the crankshaft by drilling/tapping a new hole higher up than the one shown on the crankshaft/flywheel connector. Any tips on RPM increase regarding this engine? The minimum to pass my class is 1000rpm, I am currently at 1890, and the average rpm achieved has been around 3 or 4k Thanks.

 

[berkeman]

Welcome to the PF. Fun project.

IMO, it's hard to offer suggestions without having much more information. What is the valve timing of this "engine"? Presumably the input pressure is used via the camshaft and two valves to generate output torque, right? What is the output load? Just the MOI of the flywheel? What is the total bearing friction torque once the flywheel is spun up?

Can you post your cam profile, and how that translates into your valve timing?

 

[FreeForAll]

If this will be free-running you can try to reduce the mass of all moving parts, especially the flywheel, pistons, and connecting rods.
As mentioned above the cam profile can also be a limiting factor.

 

[JBA]

Make sure that your air supply line and engine intake port are sized to minimize any flow air friction pressure losses from those sources and that you are not losing engine input pressure from approaching the maximum air supply delivery rate of your air compressor.