Ok, Educate me please:

Need to know what the Ackronoyms "TDC and BDC" Represent? Something that I have NEVER done is work on my engine. It loses compression or what have you when stuff goes wrong, I end up replacing it.

Yes..I know. I"m pissing money way. I'd love to get the 411 on engine repair and maintenance. It'd be helpful. (or at least a source where I can be educated further about engine care and maintenance)

Thanks!