Warning--Pilot Automotive Nitrode Spark Plugs SP-NP28

int77345

Active member
scout II 345 4bbl carb, igniter ignition 400,000 mile engine...

this post is kind of a continuation of my last post on my misfire problems. after curing the misfire with cap, rotor, wires, plugs and coil, i saw an add for this fancy Nitrode Spark plug claiming more spark and claiming to be the best anti foul spark plug ever.
my 400,000 mile engine tends to foul plugs every 2 years or so, i think most of the problem is the engine is worn out, and the rest of the problem is all the elevation changes the scout sees. from about 5,000 feet to about 14,000 feet regularly. if you want to see some pictures of our camping and trail riding look up coloradoscoutii on Instagram.
so i ordered a set of these fancy spark plugs, installed them went for a drive and immediately noticed my idle was down below 500rpm. pulled over adjusted the idle back up, i like it just below 700. also the engine was not running smooth at all, and my vacuum gauge was reading lower then normal. pulled over again and adjusted the idle mixture, but could never achieve normal idle vacuum. continued driving for about 30 min and the motor ran worse and worse till it was misfiring, back firing out of the intake, barley accelerating. got back home, next day took a look at the Nitrode plugs and all 8 were totally black with soot, and some had raw gas on them. so bad that i though my floats were stuck open and raw gas must be dumping down the intake. took a look at floats, floats seemed normal, gas level in bowls was normal. tossed the Nitrode plugs in the trash and reinstalled the NKG spark plugs, and went for a drive and the scout ran perfect. had to re adjust carb back to old settings to get idle to come back down and get normal idle mixture vacuum

long story short beware of this Nitrode plug, save your money and get the plugs that have been around forever and work. maybe the Nitrode plug would work with way more ignition voltage or with coil packs like modern cars have. but for 70's style ignition systems, this plug is a total failure
 
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