remove dist cap and turn the engine over via large wrench on harm. balancer nut. once you see the rotor turn, stop and go back counterclockwise....if it takes a while before the rotor starts to turn the other way, you have mucho slacko in chain. I just replaced one on a 258 2 days ago.... If you pull the cover at all (even to just inspect it, go ahead and replace it.) If you have a timming light, you can see if the mark jumps around several degrees.
1975 CJ-6 1983 CJ-8
1986 CJ-7 Laredo 1986 TJ-7 Trail Jeep
2003 Inca Gold TJ Rubicon