It might not look much, but a lot of thought and calculations have gone into producing this drawing. Bob has been hard at work putting the base dimensions together, working out the minimum rod length we can get away with to make a compact engine.

The rod length is critical as too short will have it colliding with the sleeve, but too long sees an unnecessarily tall engine. The clearance between the sleeve and flywheels is also critical, as I wanted to avoid having to chamfer them. For balance we now know that the maximum rod deflection happens 74 degrees either side of TDC.

A slight surprise to me is the overall height of the engine. Ok, so a 2.75 litre single is never going to be small, but the complete motor is looking like 30″ top to bottom. (or 75cm if you prefer). On the Dnepr outfit that puts the head level with the top of the tank!

But it’s still doable. In fact I like the fact it will look imposing, neat and different. All I need to do now is locate some parts!