I will be also converting my NT.16 to .18 size engine. My local hobby shop says that for starting any new/rebuilt tight engine for the first time use a hair dryer to warm it up (~190F), loosen glow plug 1/4 turn and always mark the flywheel to indicate piston in the down positon. The piston should be in the down position after every run to protect the piston/pinch of the cylinder. I will try their advice and see how it goes for my conversion.