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My cylinder liner is just over 4" long but at 20mm bore I had to cut from both ends so the 'step' was in the combustion chamber.

Back in the days when people had steam engines or petrol engines to power their workshops Henry Greenly gave a design for a compound condensing engine with a flash steam boiler which was claimed to require little attention when in operation. The book I have taken these couple of pictures from...

Nicely done 👍 👍 I am interested in your use of ball races for the main bearings in a built up crankshaft but conventional split bearings for the big ends.

I am slowly building an single cylinder opposed piston two stroke diesel with side pull rods for the top piston. I have question about your plans to make a single cylinder version of the Gobron-Brillié. As I see it the two pistons stop the top yoke from twisting, if you only have one piston it...

Excellent, you obviously now have enough compression. If there was oil in the blower it could have produced a mechanically atomised mixture that would fire.

Holding a burning diesel soaked rag in front of the air intake is a traditional way of starting cold recalcitrant diesels. You can't plug in heat gun in the middle of a field.

Good luck with the next steps :) When I built my two stroke I had to reduce the combustion chamber to about half the original calculated value to achieve ignition. I had compensated for the port position but the clearance between the piston and head was more the planned and I think heat loss...

It is certainly being starved of air. Can you add the blower/compressor or is that too much work? Have you measured/calculated the actual combustion chamber volume? Tolerances can build up in the wrong direction.

I have two engines running with petrol injection. The full details are on MEM. Both use manifold fuel injection with the same design of mushroom/poppet injector I use on the diesel and have slide throttles. The 25cc single has a variable stroke pump where the speed - leakage characteristic...

Those are some interesting thoughts I got out my compression tester, a small thermocouple and the smallest O rings I have, 2mm bore 1mm section. I think I could open the nozzle out to 4mm bore to take an O ring however I don’t think I could get the thermocouple in as well. I might make a plastic...

I agree with continuing with the fuel pump, that's working in the direction you want to go. Munich is around 4 hrs from me by car or train if you are interested in meeting up. There is also a German model engine maker I know who lives just south of Munich.

Thank you :) I will look into that. I have been using a ss ball in a lapped seating as I do for my injection pumps which seem to work well in an oily environment. As the compression tester is dealing with hot air another solution maybe required. I am interested in your temperature measurements...

Difficult, as you already have a pre-chamber purging the burnt gasses around the sparkplug well enough to get some fresh mixture in to ignite may be a problem.

This is my compression tester, I have tried to keep the non return valve as close as possible to where the injector nozzle would be. I have had problems getting the ball to seal properly at the end of a deep hole.

I first ran my two stroke diesel on petrol to confirm that the ‘two stroke’ induction worked. It was designed to allow this so there was not too much work involved. You may have rather more work to reduce the compression ratio and get a sensible gas flow to a spark plug, probably a new cylinder...

I guess this is referring to my cylinder liner. Yes, it is designed for water cooling and will have a water pump to allow load testing if it ever runs well enough. The engine build is here: https://www.modelenginemaker.com/index.php/topic,8690.0.html I load test all my engines when they are...

The Acrolaps are quite simple, there is a cone shaped piece that screws into one end of the brass bush to expand it, the other end of the bush is screwed onto the mandrel. The expander and mandrel cover a range of sizes, in this case 15 – 25 mm which covers my range of engines. To start lapping...

I guess this is referring to my cylinder liner. Yes, it is designed for water cooling and will have a water pump to allow load testing if it ever runs well enough. The engine build is here: https://www.modelenginemaker.com/index.php/topic,8690.0.html I load test all my engines when they are...

Some interesting questions. Firstly, I am an engineer on the Autistic spectrum so I need to understand how things work. I have some experience with small full-size engines via motorsport and preserved narrow gauge locomotives. Before I start an engine design I will see what I can research and...

Lapping the cylinder liner for my Junkers CLM: