Thread: would hi-mileage/worn spark plugs cause KR at WOT/PE?

curernt running AL103s with the spark plug mod of cutting the electrode arm in half(search for it) and regapped it to ~0.040 since its also what the mod instructed(gap 0.010 less than the normal gapping range). i honestly dont remember how many miles was put on it, but the drawback to this plug mod was having the life of the copper plugs shortened even more. i think i put approximately 2-3 oil change miles on, meaning ~3-5000 miles on them.

pardon my noobish question, but would the extended life of the spark plugs be causing my KR recently occurring at WOT above 70% throttle? my WB's at a decent 10.3-10.6 which is alright for my mod list. IPWs were ranging in the 18-19 with the 3.0" pulley and 42.5# injectors. i did not log a scan, but from glancing over to the palm's LS1M, i saw as much as 4-5* of KR. motor's still good and no SES nor misfires occurring...yet , but thats for another topic. my question again is, would worn out spark plugs cause KR at at specific area such as in PE/WOT only?

thanks for reading this long question

I run sidegapped plugs as well but mine are 605's. But I definitely believe that with how they wear a little faster that it could be a source of KR. Ive seen mine wear the center electrode at a 45* angle. I hate to give up the good spark exposure though.

But I do have a suggestion for you to help out if you desire to keep using the sidegapped plug. If you have a cryo treatment facility near you, give it a shot and have them cryo treat a set of plugs for you after you have sidegapped them. I can get you some information on that if you like but it is supposed to greatly extend the life of the plugs.

cryo spark plugs? you have cryo on the brains......

that would kind of defeat the purpose. it would be cheaper to just by a new set of plugs and replace, and wallah!! no more KR.

Yeah, its definitely a possible source for some if not all the KR. If you think about it, the wear on the plugs causes a wider gap which makes the spark harder to ignite or weaker when it does.

Though, in all fairness to that idea, I would expect you to see a richer mixture because of it and it doesnt seem that you are.

wouldnt you run a little lean? if the spark is not igniting all of the fuel in the combustion chamber? all the compressed air that is constant with unburned fuel?

more air to fuel?...lean?

Not necessarily. You would have more unburnt fuel. Vapors of that unburnt fuel would make it to the O2's and they would read that extra fuel. He's probably sparking, just pretty weak if the gaps are wider than they should be.

Try the new plugs only gapped and scan. Then if you want, side gap the plugs and do it again. My car did not like the AR 103's and they had the cut back electrode. Those were the only plugs out of all I tried that it did not like.

However, most say the AL plugs are only good for 10K so cutting back the electrode reduces the life even further, You're probably close when you say two oil changes worth of time.

Yeah, but its worth it to me. I made it my mission after using my first set of sidegapped plugs some time ago (long before the GP) to find a set of factory made sidegapped plugs or plugs that used that principle. I thought I had found it in the E3 plugs but I ended up shorting out two of them internally so instead of getting a new set I just moved on.

Im hoping the LGS plugs will be what Im looking for as they seem to have all the principles of sidgapping incorporated.

I figure if sidegapped plugs are good enough for top fuel cars then they should work just well for me.