Scott Bunn wrote:As we are talking about spark, should one be considering upgrading the coil for better spark? I have seen some with Mallory distributors and Hyfire coils. I am not looking to race professionally but would like the most bang for the buck. My opinion mostly is if is not broken dont fix it, but again....
My mostly "academic" understanding of what you get with an aftermarket "hotter" coil are these things:
1) presumably equal or better construction quality to original (many ignition coils still operate after 20 years, so original parts are probably sufficiently good for most drivers. If a designed-for-racing coil worked better, but only worked better for 2 years until it left you stranded on the side of the road, most people would agree that any beneift gained was more than lost when that happens.)
2) the design parameters of an igntion coil are selected to make a "good spark" easier to happen within a certain engine speed (rpm) range.
{ for example: An ignition coil designed to work really superbly at idle could potientially have "weaker" performance at the highest engine speed the motor is rated to run. That would probably be the best design choice for a city street taxicab. Such a coil would produce some really great spark for starting the car despite a weak battery and below freezing temperatures. Most likely at 5000rpm, the spark quality would be compromised, affecting maximum power output. That is the other result of the design choices made - optimizing the performance within a certain range. }
a fancier looking aftermarket igintion coil might be designed to be more optimum for race use engine speed ranges, a use wherein the performance of the ignition at idle speeds might be deemed unimportant. Such a coil would be advertised as being "better for high rpm," but would not be advertised as being "worse for low rpm." Both traits would likely apply.
3) heat capacity/dissipation - continuing high rpm use, as a road racing car might be used, generates more heat within the coil itself. High heat damages the internal components of the coil. Coils are usually filled with a medium like oil that passes the heat from its electrical components outward to the case of the coil, which dissipates the heat into the air. A fancy aftermarket coil is likely to be larger in size, contain more oil, and have a case with greater surface area to dissipate more heat.
Given all of that is true, which is just my unproven understanding of the system, it's likely that a coil designed for road racing use actually contains design choices that make it less suitable for normal street driving use than a nice condition original coil.
There are simple electrical tests you can perform with a multimeter in order to get a pretty good idea whether or not your ignition coil has become deteriorated or not. So far, in this lifetime, the only ignition coils that I have tested and found to have deteriorated are the compact inside-the-distributor models that some (mostly Japanese) models moved to in the 80s and 90s. Your experiences may vary.
I'm not the type of person who thinks that the factory has optimized the performance of every component on the car, in fact I usually think that while replacing a damaged part, one can spend 100% - 500% of the cost of the original part and further optimize the system, however in the case of ignition coils, my experience is mostly that the factory part works well, has a long service life, and is usually the part that leaves the least opportunity for improvement of the whole ignition system.
