Lei Siew Long

I am running a set of NGK plugs with a heat range of 7, BCPR7ES are the actual plugs i'm running, and i have been driving the car hard to try to replicate the violent bogging problem i was having before.

well, i pulled the #3 plug and the color of the insulator is a yellowish color. i was looking through my Haynes manual, since the helms doesn't have a colored picture of the plugs, and it says the yellow color on the insulator is "high speed glazing." and this is caused by quick and abrupt acceleration (makes sense).

My questions are: is the yellowish color normal and should I change to a colder plug?

the color of the plug is pretty similar to this. not exact, but, similar.

MaxSterling

go with the hottest plug that does not promote detonation. heat range 7 is good for most street applications

asiangl2

what is your setup and how much boost are you running... also what is your fuel managment???

KiddEng

i got this from a site about glazing of the insulator.
http://www.triplesonline.com/t...s.asp

"This condition may cause misfiring at high engine RPM. Shiny deposits usually suggest that temperatures have suddenly increased during hard acceleration. As a result, normal metallic deposits do not have a chance to slough off the plug and they melt and form a conductive coating which causes the misfire. Yellow or tan deposits, as shown below, usually indicate the use of leaded fuel."


the picture on the site match that pic.
running any leaded fuel? do they still sell leaded fuel at the pumps?

Lei Siew Long

thanks for everyone's posts. any other ideas?

stackz

I wouldn't worry about the discoloration of the ceramic too much. If the actual electrodes showed some sort of unusual wear or deposits or there were deposits on the ceramic or it was cracked...then I'd worry.

At worst, I'd say you're running a little lean.