Chevy Time Band

I have a problem about three months ago I repaired a Chevy engine and as a week it loves it because the time band was burst again and we repaired valves, that I correct as a guarantee, two months ago I gave it to it, but now the band was bursting again and I will take valves. What can be happening. work or not?

What year, is it?
any photo ??

It is 1.4, 2001

Greetings, you checked the crank of the crankshaft .. ??? Over time in the teeth it becomes sharp and cuts the rubber band ... you checked that the crankshaft pulley was not folded ... ???? or the gear of the camshaft .. ??? or that the water pump is not turning chueca .. ???

greetings

Remember that to adjust Chevi's time band, it is necessary to loosen the water pump and turn it, so that at the time of releasing the tensioner it is not too tight. What band brand do you use ??? Remember that the best quality is AC delco or failing that Gates can also be one of the causes in addition to the advice of the companions.