engine fires every 90 degrees of crank rotation.The cam moves at half the speed of the crank.One half of 90 = 45,which is the amount the rotor moves.So the distance between terminals in the cap are spaced every 45 degrees.If your timing is locked at 36,think how critical it is to have the rotor in the right place.36 degrees at crank is 18 degrees of rotor rotation;which is almost halfway between terminals.So where is the spark going to jump to if the rotor is halfway between trrminals?And if you have vacuum advance the rotor is moving 28 degrees and that is over halfway the distance between terminals.