spark plug ?

rod · 11-29-2011, 11:17 PM

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

Tom Turner · 11-29-2011, 11:50 PM

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

Adger Smith · 11-30-2011, 10:28 AM

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

Jim B · 11-30-2011, 02:31 PM

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.

vic guilmino · 11-30-2011, 03:19 PM

my plugs have been in the mustang since 2003

Tom Goldman · 11-30-2011, 03:52 PM

Quote:

Originally Posted by vic guilmino

my plugs have been in the mustang since 2003

but you change rocker arms every other run!!

Bob Don · 11-30-2011, 04:41 PM

Maybe not with the new rocker arm rule!

Dyno · 11-30-2011, 08:37 PM

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

Bob Mulry · 11-30-2011, 10:28 PM

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...........

larrylomascolo · 12-03-2011, 09:41 AM

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

11-29-2011, 11:17 PM	#1
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 313 Likes: 0 Liked 20 Times in 15 Posts	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

11-29-2011, 11:50 PM	#2
Tom Turner Member Join Date: Jan 2005 Location: Lake Tapps, Washington Posts: 137 Likes: 0 Liked 0 Times in 0 Posts	Re: spark plug ? Is this a "pop quiz"? I really hate pop quiz's!

11-30-2011, 10:28 AM	#3
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: spark plug ? Heckeee durn it....I guess that is telling me to toss the old faitful Champion spark plug blaster. OH, Well!! __________________ Adger Smith (Former SS)

11-30-2011, 02:31 PM	#4
Jim B Member Join Date: Dec 2008 Posts: 100 Likes: 0 Liked 1 Time in 1 Post	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. Last edited by Jim B; 11-30-2011 at 02:51 PM.

11-30-2011, 03:19 PM	#5
vic guilmino Senior Member Join Date: Dec 2001 Location: wv Posts: 884 Likes: 42 Liked 56 Times in 21 Posts	Re: spark plug ? my plugs have been in the mustang since 2003 __________________ Vic Guilmino 1129 STK

11-30-2011, 04:41 PM	#7
Bob Don VIP Member Join Date: Oct 2002 Location: Greater Boston Posts: 1,494 Likes: 1,108 Liked 893 Times in 190 Posts	Re: spark plug ? Maybe not with the new rocker arm rule! __________________ Bob Don 128 SS Last edited by Bob Don; 11-30-2011 at 05:48 PM.

11-30-2011, 08:37 PM	#8
Dyno Senior Member Join Date: Dec 2002 Posts: 912 Likes: 1,123 Liked 674 Times in 201 Posts	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

11-30-2011, 10:28 PM	#9
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	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........... __________________ Bob Mulry 7516 STK A & M Motorsports

12-03-2011, 09:41 AM	#10
larrylomascolo Member Join Date: Nov 2008 Location: Ontario,canada Posts: 440 Likes: 70 Liked 66 Times in 29 Posts	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