Who can read plugs, and what do these say?

[67dartgt]

More importantly, where can I learn to read plugs? The first pic is Cylinder #1, the second pic is Cylinder #4.

[guzzimike]

Here's some info that may help....

http://www.dragstuff.com/techarticles/how-to-read-plugs.html

[67dartgt]

 

That is the coolest article ever! Thanks mike!

- Don

[That One Guy]

it's been a while, I know the first one's good, actually, almost great, you want a nice tan color, the second, you're gonna want someone else to tell you, I've forgotten a lot

[67dartgt]

it's been a while, I know the first one's good, actually, almost great, you want a nice tan color, the second, you're gonna want someone else to tell you, I've forgotten a lot

yeah, that's the crap part. If they are both out of the same motor, what then?  Mike's link has some good info. I'm going to check out everything there. Also, what about load on the engine? Should I be beating on it and then read them? Or just take a trip through town? Or does it matter?

- Don

[67dartgt]

Nevermind. I'm dumb. from Mike's article:

"This is only valid if you shut-off the engine after the finish line then tow the car back to the pits where you remove the plugs for reading !!
Or if you are on the dyno
VALID ONLY for full load acceleration or steady state dyno tests"

[That One Guy]

yeah, when we decide to check the plugs, we'll usually have a socket (and pair of gloves) in the car during the run, and check them right after the run.

[NYrr496]

To me, #4 looks like it's detonating. The first one looks ok, though.

[67dartgt]

To me, #4 looks like it's detonating. The first one looks ok, though.

After looking at the pics on the site that Mike posted, I was thinking the same. That's the reason I started looking. I hear and odd noise with the motor under load, and thought that it might be detonating, but it's hard to describe. I was going to do some testing tomorrow by taking some timing out, and playing with my vacuum advance. I have two options for hooking up the vacuum advance, and i get very different results depending on where i plug it in (tuned port or constant vacuum port).

[bOb shingler]

the vacuum advance goes to the port on the primary metering block. it's way rich but then again you didn't cut it clean. the top pick needs more timing and the bottom pic is perfect on the timing. with a msd or multi strike box the porcelin(?) should be white at the end and tan down inside the plug where it meets the steel body.

[Thin White Duke]

There's aluminum on the #4 plug.  Those small balls around the rim, etc.  That would be piston material there. 

[beeprace]

The first plug is looking pretty good. That transition in color on the strap from tan to dark should take place dead in the middle of the bend. If it is towards the top like yours that indicates slightly rich, if it was closer to the thread it would be leaner.

The second plug is hard to read at the angle it was photographed, but the color and prescence of aluminum leads me to beleive that cylinder is either lean or has detonation. It has the look of oil getting into the combustion process or very poor fuel quality.

Do not over concern yourself with the make a pass and shut it off legacy. With todays ignitions and tunnings, you can get a good reading by returning to your pit location. The idle time will not move the reading on the fire ring as I discussed in paragraph one.

I run 2 different plugs in my car to get the best egt readings and plug readings. I run one step colder plug in 1,7,2 and 8. They are my leaner cylinders.

Beep Beep Over and Out