I use a zinc additive...can't hurt! The spring pressure in these won't be too great whereas you eat up lifters and lobes like a car! Don't use a multi grade though. The thin stuff does not stick where it should. Remember, these are splash lubed, not pressure lubed. I use a non detergent 30wt oil, but I know the racers sometime use 40 or 50wt oil. Stay away from synthetics as well, unless formulated specifically for splash lubed small engines. If you can find a 30wt with zinc, I feel that is ideal!