I had this issue with my e15 distributor conversion, chased it around for ages.
As it turned out, I'd wired it wrong, I put the 2 wires coming from the dizzy to the + and - on the coil.then an active to the positive side of the coil, then a earth to the - side of the coil(to the body) WRONG
the - side of the coil cannot be earthed, or this will take the fire signal away from the coil, hence no spark.
just check that on yours.