Why is the porcelain on one spark plug discolored
11-27-2010, 04:32 PM
#1
Thread Starter
Why is the porcelain on one spark plug discolored
I pulled my plugs to take a look at them and found this.
They were all tight. The coil pack boot wasn't burnt or discolored any more than the other three. Any ideas?
They were all tight. The coil pack boot wasn't burnt or discolored any more than the other three. Any ideas?
11-27-2010, 05:26 PM
#2
very common on some plugs, it is just leakage coming out of the one plug, I've seen many engines where all four plugs looked like that. Doesn't mean anything and no harm done, it's not related to any engine issue.
11-27-2010, 07:36 PM
#3
Registered User
I'd say it looks to me like a failure of the internal insulator seal. One possible cause is overtorquing while installing. Another may be simply a defective plug.Below is a link to a cutaway view of an NGK plug eluding to the internal seals.
http://www.rpmoutlet.com/ngkinfo.htm
http://www.rpmoutlet.com/ngkinfo.htm
11-27-2010, 09:01 PM
#5
Registered User
Originally Posted by Robert O,Nov 27 2010, 11:36 PM
I'd say it looks to me like a failure of the internal insulator seal. One possible cause is overtorquing while installing. Another may be simply a defective plug.Below is a link to a cutaway view of an NGK plug eluding to the internal seals.
http://www.rpmoutlet.com/ngkinfo.htm
http://www.rpmoutlet.com/ngkinfo.htm
11-30-2010, 12:57 PM
#6
All of my plugs have always looked like that...at least, after a track day or two. Never had any problems.
11-30-2010, 01:14 PM
#7
Originally Posted by twohoos,Nov 30 2010, 02:57 PM
All of my plugs have always looked like that...at least, after a track day or two. Never had any problems.
I showed 4 of those with discoloration to my tuner and he said he sees them all day long.
I have run the iridium plugs and seen this on 11 of 12 plugs.
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