I have done quite a bit of upgrades (cheap upgrades) since swapping out my cam. New coil, split fire plugs, and 8mm wires today. The plugs came gapped at .040. I had Autolites in before, and had been experimenting with the gap. Started at .032, then up to .035. Tried .040. The more I gapped the plugs, the better it ran, but the plugs cleaned up and turned back to almost white (some had white powder on them). Dad always said to look for the brown paper bag color. Anyway, should I keep the .040 on the Split Fires now that I have a bit more voltage? Also, how long do I have to drive on new plugs before they start to show colors, so I can see how I am running? I drove about 5 miles, hard miles, then revved to 3500 for 30 seconds before shutting down, but the plugs still looked brand-new white. No information to work with.
I've always heard that to check plugs for color you need new plugs, run it hard like down the track and then cut it off without idling it. I've also heard that with today's gas it's hard to get good color on plugs. Also that if you're using ignitions like an MSD it's real hard to read the plugs. Do a search though as I've seen several charts on line about reading plugs. clint
If your engine is basically stock, go with the recommended gaps, etc. It takes some miles to show patterns on the plugs. They don't happen right away, with the exception of real problems like oil fouling and being a very rich mix. The upgrades for the wires, coil, etc are good choices, but I have reservations about the SplitFires. I tried them on an older motorcycle I used to have and they weren't worth the powder to blow them up. I have heard the same from several others that used them on various makes of cars. Personally, I'd stick with Motorcraft or Bosch. Another thing I recently learned is that the platinums won't make a significant difference on an older engine. Don't waste your money.
I kept the old plugs, as they were in real good shape, just in case the splitfires dont work out for me... Only takes 10 minutes to swap out 6 of the 8 plugs, then 30 minutes each for 2nd and 3rd cylinder...damned shock towers!
Split fires were quite expensive, but I was willing to spend $50 to (maybe) pick up some horses. So far, only 30 or so miles into it, I am not dissatisfied. I don't think there was tremendous gain, since I didn't get to the track today to verify it, but it "seems" like they run a little better. The back end tends to slide around corners, which it did not do yesterday. But that could be the coil...I don't know?
Plugs Splitfires are just a sales pitch. Anytime you change to new plugs it'll run better. That's their trick. Plug gap will depend mainly on the ignition system. Points or electronic. Points can't make the power to jump wide gaps. Wide gaps produce more spark. Some electronic systems use as much a .054" gap. Points .038 is about max.
There will be absolutely no horsepower increase. But some people have plenty of money to spend, so to each his own...
splitfires.. always thought it was a cool marking dealo. use to run them in one of my motors that use to leave alot of oil on the pulgs (oil fouled, it was an old motor) but you know what... with the splitfires the plug were cleaner hands down and this is even over extend period of time. so i'd say they worked for that engine. now on the other hand i ran them in my wife's sentra just for the heck of it. within less then three months the plugs burned down the the ends of the diode unevenly (hense the "V" shpae). it must have crated some sort of condition and made the car ping like heck. i ran them again just to see what would happen. it did it again... i sent them back and they game me my money back. now i run nothing but bosch platinums in that car. never had that problem again. sorry it was off the subject so back to one of the questsions; i'd just run the factory suggested gap.
I put Splitfires in my Yamaha and they actually helped get rid of some resonance at certain RPMs. I got em on sale, and with the prices on motorcycle plugs what they normally are, they really didn't cost any extra. They don't really do as claimed in most cars though. For those with some memory, there were surface gap plugs that were the same concept that went all the way back to the 60s.
I don't know if it was the plugs, wires, new coil, recent cam swap (last week) or what, but when I used to start it up in the garage, my wife would bit...er, complain that the house and all my clothes smelled like gasoline. My dad would walk in and say, "yep, reminds me of how my ol' 69 Road Runner smelled." It stunk so bad, I was actually thinking of puttin on catalytic converters. Now, just this week, I can start it up inside the garage, with the choke on, and smell hardly any gas. After it warms up and the choke kicks off, I smell nothing. I drove it to work two weeks ago, and after starting it, had to back it out of the garage and then come back inside, change clothes, then drive to work so I wouldn't smell like a grease-monkey during my meetings. Something has changed that is causing better burning of the fuel and MUCH less smell, and my eyes don't burn when I run it in the garage anymore. Which of my improvements helped? All of them?
