Anybody have any particular performance spark plugs they prefer to use? Their for my 89 5.8. I was looking at the E3 Diamond Fire plugs...but there really isnt anything special bout them...other than the "diamond fire". I like iridium plugs but their expensive as hell.

 

Basically any plug will work, even the cheap motorcraft and autolite. All plugs do the same thing no matter what compound, 50,000v goes through any plug, and the more expensive plugs only still put out what the coil sends it, besides, you can get as many miles out of a reg plug as a high dollar plug, just pull them out and clean and regap, good as new. I got about 60,000 out of a set of motorcrafts in my old truck, and had another 40,000 until I sold the truck.

 

What ever plug you buy dont buy Bosch platnum plugs. Everything else seems to be pretty good. Bosch plugs can fall apart in the cylinders and cause all kinds of problems. First hand experience with that a couple of times and on different vehicles. The ceramic seems to get brittle after about 20,000 miles.

 

Ditto! Took out 2 cylinders. 8 C-notes later, I went to ask a Ford Mechanic I'd met about it & he said Bosch Plats can't take the heat. He said he gets 4-5 / year however most are in twin OHC's 4 bangers. As w/ mine (94 escort), the insulator & center electrode break away and raise hell. Anyway, on my 87' 302, for a stock gap plug, I really liked the AC/Delco 2x Plat Finewires. A friend who worked at a wholesale supplier recommended them to me, offering to buy them back if I didn't like em. I was very pleased w/ em. Sometimes while waiting at stoplights, I would swear the engine stalled as it idled so smooth. But, cause I always wanted to try it, I went to stock Motorcrafts, sidegaped them and stretched to gap from .044 to.056 and next time I change plugs, I'll try .058. I noticed I can only get 14 BTDC w/Plat plugs w/o ping @ 89 octane. With stock sidegaped Motorcraft I can do 16 BTDC w/ 89 octane but I use 91 just to be safe. This is w/8.5 wires/ brass C&R & the 60K Coil.

 

Awesome thanks...great info, I don't have a whole lot of experience putting a wider gap on my plugs so thisll be something good to try. Explain what sidegapping is.

 

Here's the scoop on sparkplugs. Theory/function, minus all the B.S. & Hype:
http://en.wikipedia.org/wiki/Spark_plug#Heat_range Here's the scoop on Sidegapping: http://www.performanceunlimited.com/...degapping.html Motorcraft stock coppers are the best for Sidegapping because their thermal transfer properties enable them to transport combustion heat away quickly. This allows you to inscease your rate of compression (and horsepower) by further advancement of above stock base time of 10 BTDC (I run at 16 BTDC). Coppers allows much more advancement than Plats. They don't last as long as Plats, but I like to see what my plugs are up to a lot more than once or twice every 50K anyway. If I read this, I'd ask:"If sidegap motorcraft are so good, why don't they make one?" Well they do! It's a limited production (last time I checked: $8/ea.), special application (haulin ***) plug. Ya have to special order them. This is about where Octane should come into the conversation, but thats a whole other can of worms. Note: I don't recommend anything I haven't personally Guinna Pigged. I've run @ 16 BTDC (stock is 10 BTDC) w/ .056 sidegapped (stock is .044 standard gap) for a little over 10K miles. 87' 302, 2WD w/82K. 17/23 mpg/89oct.(91 if going thru both tanks nonestop or towing). It does require some extra maintenance prep & minor ignition system upgrades. Hands down, the most bang for your buck & quite safe when done carefully and correctly. The amount of additional advancement depend on the condition of each particular vehicle & there are some that don't handle stock base timing well (require higher than 87 octane not to ping at 10 BTDC because of combustion chamber deposits, clogged injectors, poor coolant circulation thru block, habitual misuse (according to Ford) of higher octanes at stock base time, ect...) If you want more info, let me know. My experience is w/ distributor ignitions, If your running powerpack, I believe the only way to advance base timing is chip/programming. If this is incorrect, I'm sure someone will correct me much sooner than later. There ya go!

 

I just prefer teh Autolite Double Platinum and I dont change the gap....

I havent tried teh E3 plugs yet....but even in the DP plugs I get a good 7-9 years out of them with no issue...for long plug life and cap and rotor life I leave teh gap as set...of coarse i check them for being even....

I use Autolite because they had/have the lowest resistance...meaning they get teh most voltage to the spark...and the racers all seam to use them...those and NKG (no good kind) and Denso...both of which I dont like because they dont like to be fouled and when they do they usually wont come back...Autolites will....

a wider gap means a hotter spark but it is also harder on all the components of the ignition system...it but build the spark before it can jump...so everything gets hotter and wears faster...

lower gap is alot easier to fire and will cause less miss-fires and the system lives a long happy life with minimal wear...I usually set everything at .045 and run with it...I have several vehicles daily driven and even when I check there is little wear...last car to get plugs, wires and cap/rotor went 9 years before the cap started to miss fire once in a while...

as stated dont use Bosch...I have had tons of bad luck with them...gotten cars in with them and I couldnt get some of them out...and they broke off...new ones wouldnt go in easy when another plug screwed right in....I just find them to be cheaply made...

 

What a great post to read immediatley after puttin Bosch Plats in my fiances car.

Back to the store I go!