RE: Can't Get new Enging to Turn Over
Not every single nitro engine has a tapered piston and sleeve. Some, [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXVB97&P=0]like this,[/link] are ringed. But, yes, if they are not ringed then they must be tapered to have compression.
The problem with the new OS 30 is simply too much pinch. It's a common problem with new engines and can be very frustrating to get past. If that bump box you bought has been sitting for years then the rubber wheel could have dried out/hardened some and be compounding your problem. You might see if you can get the hobby shop people to give you a new wheel. One method I have used on extremely tight engines is to pull the glow plug out, put several drops of oil in the cylinder and turn the engine by hand a dozen or so revolutions - just be sure to keep it well lubed.
Just take your time on break-in, try not to get frustrated, it will be worth it in the end.