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You'd need a double-ended ignition coil, but those are easy to find as they're used in all kinds of small 2 cylinder engines.

In that case don't forget about filling up the crankcase volume so your crankcase compression ratio is high enough. You might have to use flywheel type crank just to take up the volume.

If your engine is 2 stroke, how is scavenge pressure provided?

Do you have the convergent part of the nozzle too? It's not in the drawing.

Curious that it won't start if too advanced. Is it kicking back in that case, like ignition is way too early? Regarding the exhaust spooge, it kind of sounds like your engine is wet stacking, which can be a problem for full sized diesels too. Usually a symptom of the load being too light for...

A bit of a tangent, but has anyone tried a De Laval turbine? Seems like a better match to normal RPM ranges and retains the simplicity of a pure impulse turbine. Though you would have to make a multitude of tiny blades.

I spent today doing some odds and ends parts of the engine project. The crankcase has been drilled and tapped for mounting brackets so I can bolt it to a base, I made a new washer for the timing gears, put the nylon cap on the front end of the cam, and made a starter dog and driver. After...

Have you tried advancing your injection timing? 20 degrees?

Don't give up on your metal rings, they'll bed in and improve greatly if the engine is able to run.

Almost all diesel injectors are hydraulically actuated. The detroit ones just locate the pump on top of the injector, rather than having a pipe connecting the two.

It's worth noting that modern automotive diesels are partly operating on the second cycle. Premixed combustion is preferred because it produces less pollution, but longer mixing times produce a more violent initial combustion so a trade-off has to be made. That's also why compression ratios of...

Ideally the tangential speed of the gas should be zero at the exhaust, it should be flowing entirely radially or axially depending on the turbine layout. Take a look at a turbocharger turbine and you'll note that the blades are angled away from the direction of rotation at the exhaust- that's...

The behaviour of any turbomachine has a lot to do with the pressure ratio across it. Tesla turbines are impulse turbines, in that the pressure drop occurs entirely in the nozzle and the resulting jet of high speed gas then transfers its momentum to the turbine wheel. The velocity of the jet...

propane has a wonderfully high octane rating, it's not unheard of to inject it into the manifold of diesels as an auxiliary fuel, in which case it doesn't ignite until the diesel is injected and its ignition sets off the propane. What was probably happening in your trimmer was that some deposits...

After some trials, tribulations and a redesign, here are the rockers fitted along with the pushrods. I like this system of rocker pedestals and trunnions, it turned out very nicely and I'd certainly use it again. I would however beef up the middle of the rocker a bit, I managed to squash one in...

What component is this?

Low surface area to volume ratio is definitely an issue. Heat loss rates are higher relative to the total amount of air. Likely more an issue for cold starts than once the engine gets going.

The downside to spiral taps is that in my experience they are easier to break than a standard tap (also they don't seem to work so well in small sizes). Spiral point is good for through holes but awful for blind holes. And of course fluteless is useless for brittle materials and plastics. Horses...

Anyone who single point cuts a thread when they could have used a tap or die has waaaaay too much time on their hands. I say this as someone who has single point cut a lot of threads. What's even better is when you can cold form the thread with a fluteless tap. No stopping to clear chips, just...

I don't often have time to do machine work during the week, but the 3d printer is at my apartment so I can sometimes print a part. I just did the rear gear cover, from carbon fiber filled nylon 6. I think this is the best part I've ever printed from this material, must have finally got the...