Cracked rear iron... I think

[Rotary Evolution]

probably would have been a good idea, the 3 piece 2mm cast iron seals just look for a reason to take out a rotor and housing so this may actually be cheaper than the alternative.

BUT

without reinforcing the block i find that they break irons with less trouble after having been rebuilt recently. the mating surfaces are usually etched together and more difficult to twist on older engines.