Re: CAMBELTS why cant design be better ?
I suspect that alfa made a mistake in the design or spec of the belts resulting in the failures and lowering of the service interval to cover themselves. Probably a much simpler and cheaper (for them) solution than engineering a fix. Fo rme the question isn't so much as why belts but why make it such that they are a pain to change. My dad had a number of vauxhalls in the late 80's to late 90's (8v) engines and the cam belt change was a simple job. The belt was always easily accesible and could be changed in an hour or 2 so you didn't mind having to get it done. With more complex engine designs it seems the cam belt is more difficult to access and as a result more costly. The result being people missing the change at the required interval.
As for which manufactuer use which approach belt or chain, it isn't normally that simple as many will have engines using both technologies out at the same time. eg the GM 2.2 petrol was a chain but the 1.8 and 2.0i's I believe are belts as was the V6