spark plug ?
 

let's say you just made a great run, pulled the plugs and each looks just like you want them to. you check your log book and find that your predetermined number of runs on that set is at your limit. you go home and toss the plugs in the dist bin. next race, it's a new set. sound right?
OK. what i want to know is why did you toss them. if there was no physical damage and no miss fire, what makes them worse than a new set?
is there some chemical or electrical change which takes place?
i want a serious answer/discussion, not a 'just cuz i don't want to take a chance' answer.

thanks rod in AZ

Re: spark plug ?
 

Is this a "pop quiz"? I really hate pop quiz's!

Re: spark plug ?
 

Heckeee durn it....I guess that is telling me to toss the old faitful Champion spark plug blaster. OH, Well!!

Re: spark plug ?
 

Don't forget that the service/replace cycle of any part or assembly in a race car is established by advice or practical experience. Aluminum rods, ring and pinion, and all wear/breakage prone components have a car/engine combination specific "replace" number of runs to ensure a minimum number of failures and or loss of performance. Although a single additional run over a valid cycle number is very rarely going to result in a failure, adhering to a schedule is simply good procedure that results in fewer "surprises". A far as spark plugs are concerned they have been cycled in the past rather than properly cleaned and dressed because they were frequently part of a parts deal and were free. Once plug cost is out of pocket Adger's method is a good cost cutting procedure to lengthen (not eliminate) the cycle number. (As long as you are not paying retail shop labor rates!!! lol)
You want to be sure not to get to the point like the guy who took such long steps to save wear and tear on his $40 shoes that he wound up splitting his $75 pants.....a round loss due to falling off a few hundredths because of overused spark plugs would fall in that category.

Re: spark plug ?
 

my plugs have been in the mustang since 2003

Re: spark plug ?
 

but you change rocker arms every other run!!

Re: spark plug ?
 

Maybe not with the new rocker arm rule!

Re: spark plug ?
 

I saw a S/S hemi pick up 50 horsepower on the dyno last summer with a set of fresh NGK plugs. Not mine. Dyno

Re: spark plug ?
 

Don,t forget known good vs. new...........

While working at the dealership all of the good techs had known good parts vs. new..... Sometimes the electronic parts out of the Parts Dept. in a factory sealed box didn't work....

With the QC we have today, new doesn't mean good...........

Re: spark plug ?
 

With the QC we have today, new doesn't mean good... Friend of mine put a new set of plugs in his 340,,ran like he had 1 plug wire on wrong,told him put the old ones back in and start from there ,ran perfect,,bad new plug or plugs