ORIGINAL: 123Cat
I think I was up the creek about piston acceleration ,and rod length , i will just ask ,
what is the accepted rod length to stroke ratio for a model diesel?, I guess an Oliver Tiger would be a good example
The length of the rod should not affect the piston acceleration, that is set by the stroke.
I think as short rod length as you can fit is the way to go. On high performance engines they take this to the extreme with different cutouts on the piston skirt and/or crank and back-plate.
On the Rex .12 for instance, you cannot remove the back-plate unless the piston is near TDC, due to the fact that the piston runs in a slot in the backplate around BDC.