I know what spark knock looks like on a plug. But what does lean look like?

 

Nevermind...I found some good info with lots of pictures

 

NGK, and Champion have some good online stuff. FWIW

 

Post a link to that, Please

 

Check this out, this guy has good pictures & words to explain what you are seeing. the one thing I wish he had was some pictures of plugs that do have slight detonation & severe detonation.

http://www.pontiacdude.cc/

BW

 

http://www.centuryperformance.com/spark.htm

you've seen all these before...
http://www.sa750.com/plugs/plugs.htm

 

Where do they get these plugs? I dont know how many times I have seen pictures like that of plugs that are just wasted. If I EVER pulled any of those plugs out of one of my motors I would just give up & ride the bus. those are just pathetic.

BW

 

Stick to the NGK and Champion sites, they are written by folks that know plugs. If you can find the old issues of Circle Track and Race Car Technology, Smokey Yunick did a series of articles back in about 94, that has some great data.