RE: NITRO ENGINE HELP
There's a good motor section here at RCU that many people have contributed to concerning hop ups. Lots of the car guys are really into hop ups also, and have started a few good topics...i've swiped ideas from them also.
I like to dismantle and work on motors also for my boats. Usually its because I've bought them used, some with very little run time, and just never put away properly.
I'll do the same as you and do careful stock removal to help airflow, but been finding the patternmaking of all the newer motors is quite good, and theres usually only small steps that need taking care of but its satisfying to know at least its been looked at.
Your right about the sleeve fit, some of mine by the time I've removed the sleeve and cleaned the case and sleeve for assembly, it will have lost some of its fit. If that is the case, when the block is warmed up to put new bearings in, i'll slip in the sleeve at the same time and use a rolling paper cut to size and layed onto the exhaust side surface. It forms just enough of a gasket to seal it well, but not enough to distort anything.
I always upgrade to stainless steel bearings, and some I will be trying ceramic bearings in the front where vibration occurs due to flywheel balance - hopefully to time and match the wear that the rear bearing sees.