I would like to know how after market spark plug affects engine performance. Also, what is the best way to the best way to check spark plug efficiency. Any help regarding this is highly appreciated.
What matters is that apart from physical fit the spark plug has the correct heat range and gap for the application. Spark plugs have advanced greatly over the last 40 years or so copper cores and double copper cores have made the heat range covered by any particular plug type number wider together with the much higher secondary voltages of modern ignition have made cold fouling and electrode overheating virtually unknown.
First introduced to the aftermarket late 1960's exotic electrode types ie, Platinum, Double, Platinium, Iridium, Double Iridium and also multiple side electrodes have enabled the life of spark plug life between changes to be extended to in some cases the manufacturers states "the life of the vehicle" (! ? ! )
For the most part where an engine uses standard 14mm thread or old style Ford 18mm thread the recommended spark plug from a reputable generic manufacturer such NGK, Beru, or Champion will be fine --- personally NGK is always my first choice.
However the development of direct injection and other exotic engine types has caused the development of specialist designs of plugs in these cases or other where there is some unusual spark plug feature stay with the OEM plug AC Delco for GM , Autolite for Ford, Bosch or Beru for most Euro boxes, NGK or Hitachi for most Asian.
As for checking spark plug efficiency apart from visual inspection for electrode wear, over heating and cold fouling, the only way is to look at the primary or secondary voltage or primary current with an oscilloscope. You can also look at the misfire counters,
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Last edit: 7 years 9 months ago by Andy.MacFadyen.
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