NZ_AE86 wrote:Well you must have no idea what you are talking about! Cambelts become loose, slackness between pulleys which will hurt performance, only a little but it does happen! Stretching causes the same problem, it not only plays with your cam timing but with you ignition timing as well.
i agree with the become loose
and i agree with the fact they do sometimes need periodic matainace
btu if you look after your car properly it sould never be a issue
we did a strech test on a cambelt at uni we got just over 1mm of strech over the entire belt before it broke
in the real world 1mm wouldnt even cover the backlash in the cam drive gear
and would not even change the cam timing as much as a good skimm of the head
maybee your thinking of timming chains ??
just my thoughts
v