Honestly I do not think automotive techs would know the answer to this question so being said from a physics stand point about the relationship between the high voltage spark on a spark plug and compression in a engine. I have had experiances where there was spark on the plugs but the engine would not start. Classic example is the 1990s hondas. I have seen examples that if the spark is weak, a strong engine with high compression will prevent the spark from jumping across the plug. Or am I wrong? What role does compression play in inhibiting the spark from a spark plug to jump the gap? I told the owner these HT coils have a weak dialectic insulation in its design. I told him because he never replaced the plugs, it loaded Coil with to much air gap resistance. The plugs had a excessive spark plug gap. The coil properly ohmed out on the primary and seconday and would fire out of the secondary of the coil using my hand to ground. The spark would not jump from the screwdriver to ground when inserted into the spark plug boot. Am I correct, that because the owner neglected to replace his plugs, The resistance leading from the top of the coil to the cathode on the plug was greater then the resistance in the coils secondary dialectric material that the spark blew a hole though it to ground? Am I correct that the coils KV also increased substantially from the excessive spark plug gap? Lastly, how is HT spark on a plug change with increase or decrease in compression?