Has anyone pulled a plug at 30k or 40k to see how they looked? Just curious if anyone cleaned or replaced them. (ya I know they say 100k miles before replacing them... ) I'm not going to wait that long...

And or anyone noticed a difference with any aftermarket plugs?

 

There platinum tipped plugs... why would u want to replace them, anything aftermarket wouldn't necessarily be better other than they would be "newer".

 

replace, nah not neccessarily...

Mabye just clean. I'll pull one out this weekend and take a look at it...

 

take one stock plug out and check yourlself..you will see

i have only 17000 miles on my cl-s, and the stock plugs are dirty as hell.

i can take some pics of the stock plugs if you want

 

Take a picture. I'd like to see them. Any comments from the mechanics on the board if they are dirty after 17,000 miles???

 

I'll go pull one now and take a pic....

check back later...

 

this is at 26,000 miles. Actually looks good to me.

 

Normal condition:



Grayish-tan to white in color indicates the plug is operating at the proper heat range as well as correct jetting and the cylinder is running healthy.

Worn Out Condition:



Excessive electrode wear, misfire during acceleration and hard starting.

Simply put as in it's description, it's worn out ... it looks ok color wise, so replace it with same plug or at least compatible heat range. You've all heard the term " If it works, don't fix it". Don't look for flaws with this plug ... just blame yourself for not changing it sooner


Mechanical Damage



This is caused by foreign objects in the combustion chamber or an improper plug reach where it contacts the piston. Even a piece of carbon can do this.

To solve this, make sure you have the correct length tip spark plug as well as removing any foreign materials in the combustion chamber. In some cases you may have excessive carbon buildup on the backs of the intake valves that will have to be addressed.


Detonation:



In cases of severe detonation, insulators may become cracked or chipped. Improper spark plug gap settings will also cause the insulator tip to crack or chip.

Detonation is tricky ... make sure that you are using the correct octane fuel first and then verify correct ignition timing. Next check for an inoperative EGR system (if equipped) as well as proper function of the Knock Sensor (if equipped). Also, you will want to make sure you are using the correct heat range plug.


Overheated:



On this symptom you will notice a chalky appearance, white insulator, rapid electrode wear as well as an absence of deposits. The actual shell may also be discolored.

To cure this you must first verify that the plug is the correct heat range, the ignition timing settings are correct, the air/fuel mixture is not too lean, there are no vacuum leaks and that the EGR valve (if equipped) is functioning properly


Ash Deposits



These are light-brownish deposits that are encrusted to the ground and/or center electrode(s). This situation is caused by oil and/or fuel additives. This condition can cause misfires.

The cure for this is to verify worn valve guides or valve seals, not using fuel additives, or you might even try changing fuel brands. By the way, a hotter plug is what most people try to fix this problem. You need to first understand that the plug is NOT typically the problem


Oil Fouled



Oily coating caused by poor oil control. Oil is leaking past worn valve guides, piston rings, or on some race engines a possible intake gasket leak and then entering the combustion chamber.

Check for worn valve guides (NEVER knurl valve guides), intake gasket sealing alignment, as well as worn cylinder walls and piston rings. A leak down test is a good place to start for what is causing this.


Initial Pre-ignition



This will usually look as a melted center electrode and/or ground electrode.

Check for incorrect heat range plug, over-advanced timing, lean fuel mixtures, inoperative EGR valve or Knock Sensor (if equipped) and also look for hot spots or deposit accumulation inside the combustion chamber.

If you or your engine builder took the time, all areas of combustion chamber should have been de-burred to eliminate this problem. This includes the sharp edges on the chamber, piston top, and cylinder wall valve reliefs (if applicable).


Sustained Pre-ignition



This will be pretty obvious ... melted and/or missing center and/or ground electrodes as well as a destroyed insulator.

Check for incorrect heat range plug, over-advanced timing, lean fuel mixtures, inoperative EGR valve or Knock Sensor (if equipped) and also look for hot spots or deposit accumulation inside the combustion chamber.

After you see this, you'd better look for possible internal engine damage as well. (pistons, cylinder walls, valves, rings, etc.)


Carbon Fouled:



This is very common visual condition on our race engines. Soft, black, sooty, dry-looking carbon. This indicates a rich mixture, weak ignition or wrong heat range plug (too cold).

You will first need to verify plug heat range. On carbureted engines, check choke as well as choke pull-off (if equipped) for proper function and adjustment. On fuel injected engines, check for clogged injectors and the cold-start valve and circuit. You also need to check for correct fuel pressure settings.

As a general rule on all computer-controlled engines, you need to also make sure that all input signals to the computer are working and accurate. This includes, but is not limited to, all temperature and pressure sensors as well as the EFI system components.


Whew! That was a lot of copying and pasting!

 

SiGGy,

Your plugs look mah-vel-ous.....

 

Tom2,

Excellent review along with pictures of various conditions of plugs. This should be FAQ'ed. Soopa or Chad, can you archive this thread?

 

It looks the same to mine after I removed them at 30k miles...
Those pics indicate that your plugs are in excellent condition.