You need a set of feeler gauges that have the correct gap for each valve spring (16 of them). You will also need to know what the factory spec is, as you do NOT want to tighten more than the spec. It's not hard, just time consuming..... you have to loosen the adjustment screw with one screwdriver, then slide the feeler gauge at the correct setting under the slot, then with a different screwdriver tighten the adjustment screw untill it just touches the gauge, then tighten the adjustment screw. Do that for each valve.