CMBracer,
The problem with the seal is not the bearings themselves but the clearance between the case and the crankshafts. This has to be made very small otherwise the leakage will be too great. All engines leak past the bearings, but the A180 was so excessive it could run with the carb fully closed!
I have no idea about Mathe's, I have never seen one. But the centre crankshaft of the A180 (unless it has been changed from mine) is not strong enough. The small 2.5mm pins cannot possibly take the load (I am a Mechanical Engineer by trade and have done calculations to confirm this). Also the use of wooden dowels for crank plugs is unacceptable. The disc float is also far in excess of any I have seen on any other engine.
I hope Paul Firmin does resolve the problems with the motor, I think it could be dominant in the hydro classes, and maybe the mono classes.
Ian.