Twin cambelts?

I just had one of my daydreams thoughts...:lol: You know how the fan belts are often twin belts so that if one snaps, the fan and water pump etc will still keep going until you replace the belts? Well why dont they do that with cambelts? A lot more important than the fan belts etc...

how much extra cost for 2 belts, i reckon at least 50%? if 1 snaps and goes un-noticed ( given there are people who dont know how to do basic things like fill washer bottles or change tyres, this will happen) and then the other snaps, you are still in the same position. i do like ur thinking though, 2 belts should last longer and offest the cost a bit

I like your thinking but I'm not convinced it'd work to be honest. Bear in mind that the belt is running under a fairly close fitting cover in most cases so there's a very strong possibility that the broken belt would get dragged into the works, get tangled up, and cause the other belts to jump the tracks anyway. Quite often with modern cars it's the tensioners or water pump that go and take the belt (and the engine) with it.

Wouldn't work, a few modern car's run balancer shafts to balance the engine when its running and these generally are driven by seperate belts by the crank, so on these engines there are two drivebelts inside the timing belt covers, I have seen quite a few engines which have suffered with snapped balancer shafts and every time bar once they have interfered with the cambelt and destroyed the valves!

Timing chains just seem to make so much more sense. A wider stronger belt would be a good idea though.