MR-12 Break in
You need to have a good supply of fuel/oil during the break in period. What you might want to do before starting the engine is to have the piston down (free play) as opposed to tdc. I use mt12 and rb x12, followed manufacturers and the document found in the link I mentioned. Never had problems. Also, remember that you "might" use more than one glow plug before you are done with the break in.