I have only done a valve adjustment once with an engine running...never again. There is no reason to do it that way. Do it once, after assembly as 76GMC said. Set your #1 cyl on TDC, compression stroke...set intake and exhaust. Rotate 90*, set #8, rotate another 90*, set #4, etc....thruout the firing order. I go only 1/4 turn after the pushrod is snug, and have never had to re-adjust. Good luck on your new engine. I'll ask you guys again in about 6 months how you like the gear drive. It gets old really fast!! I had it once, so have several others I know...none of us wants it any more...but enjoy it anyway. John