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K2, While all you have written about grubscrews and cams is correct, have you calculated the magnitude of valve train loads in a model engine? The scale factor is cubed for the mass of the parts and squared for the acceleration of those masses. I have seen lawnmower engines, many times the size...

My phone contains many photos of blackboards, whiteboards, other people's notes etc.

Not to worry. I started a thread on another forum 13 years ago and I haven't posted there for over a year. I still haven't finished the engine!

Seems like a very small carb for the size of engine (56cc IIRC?).

Ooh yes - tiny parts! Stirling engines seem to work well at smaller scale.

Hi Ray, A couple of ideas to stop your lifters from rotating: Most simple is to offset the roller from the lifter centre, so that it castors. Note that this will produce a small change to the cam timing. Another method would be to put a flat on one side of each lifter and fit a ring into the...

Our two cats like to come into the workshop and sit on the seats of motorcycles, expecting attention from me. Both of them prefer to sit on the Triumph Tigers (a '53 T100 and a '72 T100R), which seems apt.

Have you already made the 1/4 scale mill, or is that next?

Yep. Don't let perfection get in the way of good enough.

If I were to embark on a sleeve valve engine, it would have to be the Bristol Perseus... But I think we should let Foketry complete this project before we start pushing him further.

William, if you are aware of any engine which has a 7 outlet distributor, I would be very grateful for the pointer.

Yes, I have a strimmer engine and it's piston ported! Enough speculation now, I've designed a rig for testing reeds - a simple piston pump using the reed for inlet and piston port outlet with a cheap anemometer to measure air flow rate.

The intended application for the radial engine (which this distributor is a part of) is a Morgan layout three wheeler. I have it designed in CAD, but no building until the engine is up and running. The trike has a bit of a trick up its sleeve. But that's another story entirely.

FRP is fibre reinforced plastic. Strength is not a problem.

Ok, I'll bite... What is a "whipper snipper"?

Works for lawnmower engines!

Gordon, I have no doubt a model engine will work fine with a 3d printed cap in almost any plastic. However, my 2.3 litre radial is intended to be mounted on the front of a road vehicle, so it will need to tolerate weather.

The Cox reeds work a little differently to others. The reed is allowed to "float" over the port with it's lift limited by a wire clip. It doesn't need to bend to open the port. My design must be fixed at the centre to keep the petals aligned with the port openings.

The "shim" to which I refer is a specific spring steel developed for use in shock absorbers. It's very resistant to fatigue, but I can't get it in less than 0.1mm (4 thou) thickness.

Ooh, I like the magnetic pole switching idea!