I read a lot of stuff regarding Engine Timing,and since i am still learning about mechanics,i have the following questions,for example:

-SLIPPED OR BROKEN TIMING CHAIN
-WORN TIMING GEARS
-INCORRECTLY ADJUSTED ENGINE TIMING
-WORN OR BROKEN CAMSHAFT GEAR
-WORN OR BROKEN CRANKSHAFT GEAR

when i read all the above,in theory i understand that it will affect all the combustion process,intake,exhaust,performance...etc
as i ask some mechanics they get devided into two categories;the first say YES all that could cause driveability problems,while the second would say NO its impossible to happen it will damage the valves and pistons...

As far as BMW`s are concerned,how much is this true/false?

I would really appreciate any info on this topic in any simple words i can understand,or any reference or write up.

TIA

jj