As john mentioned, the secondary ignition parts are the first suspects for your trouble. The rotor can develop a hole from spark hunting a place to go. The hole will be fom center of rotor where dist cap contact touches through to underside where it sticks onto shaft. This effectively shorts out spark.
If, when you say "no ignition" you mean no spark out of coil wire, then you needn't look at cap, rotor, & wires. Then look for arcing coil top. The coil can develop an internal short where the hole where coil wire inserts gets a crack that allows the spark to jump to one of the other leads killing spark. OR your hall switch is defective. If the hall switch or the hall switch (hall switch= sensor assy. inside dist) connector is the problem then you will see tachometer die INSTANTLY when problem occurs, i.e. tach drops to 0 before the engine actually quits turning. Corrosion at the power stage connector (black and gray unit wire connector behind and a few inches below headlight level on driver's side inner fender behind air cleaner if it's a non-turbo) will cause it to die with instant tach loss also.