ls vtec timingbelt issues

[acb16a2si]

I just finished the build, but when I start the engine it runs for a short period of time, and then the belt gets very loose, and begins to flap around. What could be the cause? The water pump, as well as the oil pump are out of a SI, and I'm running a GSR timing belt. Could that be the problem? Thanks.

[teamshotokan]

what kind og vtec head are you running? if your using a head from an si, you should get a si timing belt. if your using a gsr vtec head then all i can say is just make sure everythning is lined up correctly and your timing belt is tight enough... not too tight.

[acb16a2si]

thanks im using a si head but i got it the tensionor keep loosenin up