Valve noise for toyota 93

If you are refering the "Marbles in the engine" sound, I was told that is dirty valves. It's caused by dirty gas and other dirt that gets in your gas over the years. You only notice it when a good amount of torque is put on the engine, don't ask me why. It's not a HUGE problem, but I can imagine it does cost some overall power output and should try to be maintained with some engine treatment cleaner every once in a while. I've talked to people who put it in every time they fill up, I am not one of those people. Hope that helps.