RE: Beginner Engine Help!
Garfield,
No! There probably is nothing wrong with your engine.
Please read in the first posts of [link=http://www.rcuniverse.com/forum/m_1850473/tm.htm]this RCU thread[/link].
The piston does not 'refuse' to go over TDC, due to high compression...
It probably does so because this engine has a tapered bore; and the sleeve's top is a bit too small for the piston to move into freely.
The removal of the glow-plug proves it is neither a hydaulic lock, nor an excessive compression ratio; because it would otherwise have turned over without it.
Take the engine out of your plane; mount it in a test-stand and give it the proper break-in it deserves.
To get it running you would need to heat the head and the top of the cylinder, with a proper heat-gun
There is, however, a very remote chance that the sleeve in your engine is warped/deformed, resulting in a slightly elliptical form at the top, when cold...
That would justify having the warranty work for you, if it is still in effect.
You did not inform about how, or even if, this engine ran prior to April this year...
You called it "My old Megatech nitro Airstrike with a Megatech .46 engine" after all... So, has it run and has it been used?