94 f150 5.0 130,000 While watching the rotor for movement and turning the crankshaft pulley from side to side. I got my marks on the harmonic balancer, divided the distance between my marks by the circumstance of the balancer and multiplied by 360. I did it three times and got between 6.5-8.5 as I didn't have a super accurate marking system. The question is when is it time to replace the chain/ when will it start causing functional problems by throwing off timing? I know there is some slack in the gearing of the distributor too and that slack was also including in the 6.5-8.5 figure. Can anyone offer any input?

 

8 is about the max, if you have 10 or more you should replace it.