The heat has always been the reason the condensors are made the way they are: normal electronic condensors (while being MUCH more efficient, like in Delta's setup) cannot withstand being heat-cycled rapidly to as much as 300 degrees F (I've measured close to that much on my own 750 points plate on a hot summer's day here) and then be expected to not alter in value. The automotive versions actually melt the insulator material slightly (used to be wax, now a polymer) but hold it in place so when it cools it is still OK. Typically, after about 1000 miles of use on our bikes the insulation shifts slightly in position and the condensors' value changes: depending on HOW it shifts there might be more, or less, capacitance. That's why the testers developed over the years to check capacitance value and determine if the insulator became damaged. The old wax versions, when left in deep cold for too long, drop in value about 30% until they get heat-cycled some more, which most often restores it to at least the minimum value. Since the SOHC4 capacitors were purposefully mounted sideways to reduce the heat-induced changes, their life can be much extended (in years) by swapping the lower and upper ones regularly, as this will 'flip' over the direction the insulator will move when heated. It's just another way to extend the life of these intelligently-designed (not computer-wrangled) parts.
Electronic capacitors are just made differently, usually more compactly and with more accurate tolerance of the capacitance. A worst-case X7r wrapped-package capacitor, which can take high temperature and low freezing, will shift in capacitance almost 40% over the temperature spread, and will change value as it heats up. Those of you who might remember the old 5-tube AC/DC AM radios remember having to adjust the station dial slightly as they warmed up: the better radios then avoided the use of these cheaper capacitors. But, cheap ones used the X7r temperature range parts because they were 40% the cost of the 'good' ones. I made part of my living in the 1960s and early 1970s "fixing" those venerable, good-sounding radios with better capacitors (and filters) before transistors took over. This was part of that 'tech'.
