going from memory as it is a while since i done a set there is no clearance for them just feel, slacken the lock nut and turn screw until it contacts tappet bucket and then tighten a further 2 revolutions. There is a set prcedure so as to do 2 cyls at a time, a fairly lenghty job but can be worthwhile at the end. if you want me to fax the pages from the manual give me a ring check you email for number.