Axial movement of the crank shaft within the cases isn't strictly a factor with the M20 and isn't something to be concerned about...Any axial play is taken up when the engine shock absorber nut is tightened up and the crank is pulled up against the drive side bearing..All play is then removed and the crank is fixed in position....
The position of the crank within he crank case, after tightening up the shock absorber, is a factor though...The con rod should lie centrally to the crank case joint after everything is tightened...To help achieve this the spacer between the two drive side bearings should be within tolerance (1.000"-1.005" long) and the crankshaft oil flinger plate should be fitted, unworn and flat where it sits against the flywheel and the bearing inner race...Ian
Of course. I forgot about the muffler. Thank you IAN for the comprehensive answer.
Today I will put it together as a whole and measure the axis of the connecting rod.