Picture Of Water Jacket Failure Into O Ring On Side Housing
 

Just tore down my old engine to rebuild it and found the source of the coolant issues (coolant consumption, and overflow) looks like the cold side of the o ring groove failed into the water jacket on the front side housing. This allowed the o ring to bulge into the water jacket. The front rotor housing had quite a bit of carbon buildup as well. The engine always ran great, but was consuming coolant. I was expecting a toasted o ring failure, is this groove collapse a common problem? there was only about 1/8" of iron under and outside the o-ring groove which seems a little on the thin side to me. In any case I'll be needing 2 rotor housings and a front side housing to do the rebuild- if anyone has very good or new ones at a reasonable price please let me know
tom

Tom,

Did you try the block-weld trick on this motor? I'm wonder if would have worked?

I have seen it before. Guitarjunkie even has a write up on how to repair it, on here some were.

I did blockweld it, and it worked for a while including a few track days, but then got worse. I'm surprised the engine ran with that 3/4" long piece missing. I suppose I could get someone to tig weld it but it would be a little tricky to re machine that curved groove back in there. probably be cheaper to get a new housing.
t

I had something close to that happen to me. I was shocked how brittle the o-rings were after being fried.