[Vman]

This site should provide answers to many of your quetions. It is in English only:

http://auto.howstuffworks.com/channe...under-the-hood

For engines this link:

http://auto.howstuffworks.com/engine.htm

For answers about camshafts, push rod, DOHC:

http://auto.howstuffworks.com/camshaft.htm

This link explains about differentials. I think the english term for "diferencial autobloquante" might be "limited slip differencial":

http://auto.howstuffworks.com/differential.htm

I hope these help.