RM,
did you determine the causes of the GT33 seizing?

The rebui!lt engine I just put into service seized again after 10 runs. It was the same failure mode....circlip popped off and jammed the piston. The failure occurred on the same circlip as the first time...the side of the screw port. There is an intake port on the path which does not have a rib support. A rib in the sleeve's intake port might eliminate the possibility of the circlip popping off. Or a different design is needed to retain the wrist pin.

Thats a serious design problem in my opinion. It's something OS needs to address.