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Yes I have a 3mm ball lap. It was not cheap but hopefully improves the consistency. I have probably lapped 10 seatings so far, I reworked all my existing pumps.

Some information on ball vaves that might be useful: https://www.precisionballs.com/ball_valve.php http://ibls.org/mediawiki/index.php?title=Design,_Care_and_Feeding_of_Check_Valves

This is my go to book on welding. It is available but is European. https://www.amazon.com/Workshop-Welding-Step-Step-Hands/dp/1565237412

The 4mm3 limit is the full mechanical pumping stroke of around 1.5mm. It is designed to be 2mm but for various reasons and tolerances including my timing adjuster it is a little reduced but is still more than sufficient for the 2mm3 maximum for a 20cc engine. The variation in output with speed...

Thank you all for the comments. The first engine was started in the 70s and was slowly finished when I had access to machines tools. I then went in different directions, motor sport, narrow gauge and model railways, old buses etc. I started building engines again when we moved back to...

A few thoughts based on my experiences. The compressibility of diesel fuel is not a problem in model injection systems but trapped air/gas is. An air bubble of similar size to the injection volume will completely stop the injection. The complete system needs to be designed to minimise the...

Thank you for your kind comments :) The 25cc engine is 25mm bore and 50mm stroke.

Part 2 A 12cc two cylinder four stroke. Initially with a 180° crankshaft and a constant depression (SU type) carb. Then with a 360° crankshaft and fuel injection. Finally some videos: Original engine 3cc engine. 25cc engine with fuel injection and load tests Four stroke...

A few pictures of my engines: The 25cc horizontal engine I started building in school. It will run. A 3cc vertical four stroke. An upgraded version of the original 25cc engine A metric version of Huff and Puff. A 20cc two stroke diesel. This ran but not to my satisfaction...

It’s an interesting problem to know what is going on when the fuel is injected into high pressure (and hence high density) air. My initial experiments with needle type injectors with various orifices from 0.2mm – 0.5 mm seemed to produce good atomisation but were not successful when installed in...

Excellent Progress :)

It is the Model Engine Maker Forum: https://www.modelenginemaker.com/index.php

Thank you both I have a couple of sources of diesel information, some older versions of the ‘The Modern Diesel’ and T D Walshaw’s ‘Diesel Engine Design’. (Washaw published model engineering things as Tubal Cain). Diesel Engine Design by Walshaw T D - AbeBooks The Modern Diesel - Fifth Edition...

Some thoughts and suggestions on small diesels. I have got as far as a runnable 20cc, 25mm bore 40mm stroke, 4 stroke diesel. This runs on standard pump diesel. The video is a warm start, opening the fuel rack as I start to crank. The atomisation from the injector is not very good yet. At...

I usually exist on MEM. I have made a few IC engines however I am currently working on carburettors and fuel injection systems.