Have been messing around with increasing the Gap on my plugs. And, yeah, I was running the Splitfire Platinum 2 plugs with the smaller electrode.
:oops:
I experiemented with Gap from .35-.55 (set from factory at .35 and shouldn't be adjusted, so they say). And I did seem to findthat the Platinum plugs could be gapped higher than their preset and the engine seemed to run better. Only thing was I ended up accidently damaging one of the plugs when reinstalling (badly cracked the ceramic-type material around the electrode). So I had to get another one. Go to my local auto parts store and they have practically every variety of plug listed, but only about 5 or so varieties available, none of the Split Plat 2s.
So I figured it was a good time to check out some other plugs, non-platinum, non-Splitfire. Ended up going with the 99 cent Bosch copper core plugs. The store had the 4 prong, $6 Bosch plugs but I had already tried those a couple of years ago and they were of dubious value, at least that I kind tell.
Anyway, the word going around here about Platinum plugs (let alone Splitfire platinums) not working great in Jeeps might have some merit it to it. After a couple of days, the cheap Bosch copper cored plugs I installed seem to have changed the general throttle response and torque on my YJ4 for the better, at least between about 800-3000 rpms which is where I do most of my driving. And, I gapped them out to .55 since I am running a hotter coil.
Since I bought the hotter coil a few years ago, I have only been using "trick" plugs, ie. Spitfire, Splitfire 2, Bosch 4. I believe that all of these except for the regular Splitfires are Platinum electrode types. Platinum has superior wear characteristics to Copper, but it is about half as a good as an electrical conductor.
Anyway, Jeep seems to be working great (enough so that, with 29" tires, I am not really thinking about messing with any other power upgrades). Locker is a different story though. In sum, I am probably sticking with the copper core plugs, unless Iridium or Silver-cores turn out to be a true new "magic bullet."
