Yup 0.35".

I can't remember who wrote up what was wrong with the E3s but it amounted to the alignment of the electrode and the spark actually being distributed properly... with other materials, "single platinum" ones only have one part tipped and degrade quickly on the distributor-less ignitions and there are problems with being in the correct heat range.

 

As has been said, Champion coppers, keep it between .035 and .040. I did the ACCEL tune up kit and the plugs that came in it are standard coppers so mine's been happy.

 

im all about 0-60 and i had bosch platinums(heat range 9 i think) in for 30000 miles. they ran good but when i pulled them out they were all white and chipping. never that again lol. Put the new champions in gapped to .040 def more power but thats with the msd ignition coil.

 

Good to know. This is what I was thinking of but wasn't sure, so thanks

 

heh!
fify lol

 

Thi is good info.

 

So is .50 the magic number now haha??

 

Never seen any point in running fancy plugs in a simple engine. The Champions work great in a 4.0L. Change em once a year if you want to spend more money, you'll get more benefit than you will with fancy plugs.

 

A long time ago I had the urge to try out these fancy bosch plugs in my 95 they were very expensive 4 tips made out of unicorns whatever they are lol. The jeep ran like crap. From there on out I've used plain old champions and the jeep ran like a top whenever someone asks me what plug to run I always suggest the cheapest ones. Champions or autolites. Spend your $ elsewhere on the jeep if you really want to improve performance.

 

Ok ok the e3's were not the best. I took the whole 15 min and swapped em in and took it for a drive and my Jeep was misfiring and at stops would drop to about 250 rpm out of no where then go back to about 700ish. Yes all the plug wires were connected correctly along with ends on cap. Well after that i swapped back in the good ol' champions slabbed a bit of antisieze on em and gapped to .50 due to my upgrades i have. Jeep runs awesome now, pickup is a lot better along with idle amd startup! Next is a better coil and i should have a pretty good setup i hope!!

 

i have a walker down pipe stock dia but w/o the pre-cat. then high flow cat into a 2.5 flow spr44. also got a cold air inake. what gap should i run?

i run coppers @ stock gapping. good to go

 

0.035". Don't bother messing with it unless you upgrade the fuel and ignition systems.

 

X2. Champion copper or any other good copper plug are fine. The 4.0s do not like platinum plugs. As another member stated, its really a waste of money unless you upgrade the entire ignition system to match.

 

I run regular platinums and they work fine in my XJ

 

Coppers at .50!