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plug failure thread

7K views 82 replies 29 participants last post by  Wikdsvt 
#1 ·
With all the failures over the Yrs of plugs


Everyone who has had a failure post up what cylinder or cylinder it was

Post up your fuel rail setup

Post up regulator setup
 
#16 · (Edited)
Back in the day. several times.

plugs 3,4,8 (different times)

tr6 and tr6ix plugs, i dont recall exactly which or when.

All had opened gaps and cracked /missing insulators

Stock block, 15-17psi with kb2.3, 91 oct, stock fuel system with 255 pumps and 60LB INJECTORS

All happened at either on freeway kickdowns or extended WOT runs of 120+mph
 
#22 ·
Tr6 pump gas
97 rails and Aeromotive regulator
255 pumps stock lines
litter every cly but 3 I think

Br7ef same system 6 and 8
 
#23 ·
Does plug failure also count for blowing out the head?

If so last cylinder passenger side. NGK plug (can't remember the number of the plug) stock fuel system.
 
#26 ·
Yeah not sure where this is going :smt102. There are so many scenarios of plugs and/or combinations and failures associated from so many different things. Weather it's not enough octane, too much heat, wrong gap, fueling or lack of, blow by, etc... I would hate to have to list all the plugs I have burned up in 25 years of racing. We all know why it happens !!
 
#27 ·
Well so far what we have gathered is 4 seems to be common

Local setup recently had a failure of 4&5
Timing mark was middle of bend on strap
Timing was 14*
Afr showed 10.8-11.4 thru run
Had SD 80s
Br7ef plugs

All plugs had similar timing marks
But 4&5 showed no fuel ring what so ever and part of electrode was slightly melted

Which we were pointing fingers at fuel supply of rails and regualtor setup

Seemed as closer to the loop the less fuel on the porcelain you seen

This was all verified by cutting threads off the plugs and reading them


So thread was made to gather as much info as possible as many tuners with good reps all have issues... So what is common denominator
 
#29 ·
I would establish the correct cylinder numbering. I have seen more than one occasion where they think it's right but it's not.

Tuning using EGT is certainly the way to go. I would love to have a probe for each cylinder and then you would also know where a problem is if you are chasing an issue.
 
#30 ·
Our computers are not sophisticated enough to tune individual cylinders. The new Copperhead computers will allow that along with the speed density aftermarket systems. So what do you propose, even if you have EGT sensors in every header tube, and the temps prove that there is a fueling problem to that cylinder.
 
#35 ·
Well, we would have to tune to the leanest/hottest cylinder in our case. Or we could have injectors tested and use the ones flowing more on the hottest cylinders. It is a lot of work to unlock a bit of horsepower safely. Most are fine leaving that power on the table and run richer than optimum.

Jim
 
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