So my thoughts are to make 9.5mm bore engine with a 10.5mm stroke. It will be a steel liner, iron piston. So far I am thinking of making it a simple with drilled holes schnurle type transfer system, with a side exhaust. As I will throw the model with my right hand, it will have a Rh side exhuast. I am thinking of the carb being like amills type, but with the induction under neath the exhaust port, so piston ported.
Initial timing numbers are the transfer around 120 deg and the Exhaust around 130 deg duration. Induction will be in the 110 to 120 total induction range, but thinking closer to the 110 at this stage. All the transfer passage volume will be in the liner wall, a bit like the OS12 engine does. The liner will have the cooling fins cut in like Cox engine. But will have a screw over Ali head for the comp screw. The outer Ali part will be 4032 . Not sure of the case material yet. May make it as an experiment in loss wax casting and get it cast in LM13. Been thinking of making the liner from A2 tool steel. Rod will be 2024, wristpin will be a needle roller and a press fit to the piston. Crank I am looking at either 4340 or H13, and nitrided for the crank pin hardness, but masking the threaded area. It will be a bronze bushed case.
I wont be starting any making on this project untill, sept / October or so.
If there is any real stand out issue with materials I have chosen, it will be appreciated to have suggestions for better materials.
Neil