I don't think excessive crankcase pressure will be an issue with this engine anymore ;). This is the one I blew up in my lawn tractor last week. I still haven't taken the engine apart, I only took it out of the tractor, but can't understand why the hole is not inline with the connecting rod. It's right off to the end of the engine. I even considered that it might have been the timing chain let go, but that's at the other end of the engine. You can see the end of the camshaft through the hole, but it's not scored up or anything - the cam looks fine (from what I can see). I guess the only way to tell what happened will be to take it apart...
The new tractor is pictured also. Ain't she a beaut? :D