Reading spark plugs - when to change

[Big Red VF-SII Go-kart]

@3rspecB, it is odd that your plugs are worn @ 47.5k kms yet the service life is 140k kms?

What was the reason you looked at the plugs so early in their life and what would be the cause of such an early demise?

Those plugs look absolutely fried, with virtually nothing at the tip to fire. I agree totally that the reason for this (<50k) needs to be established, and very preferably before putting in new plugs. The IR/PL NGK plugs are characterised as 'hot plugs' and very long life for these engines. I would not substitute anything else without due scrutiny to their application relative to engine.

 

[Immortality]

The plug itself looks good (electrode and earth strap), the oily type deposit is the only thing that I find interesting on such a new engine. Does it use any oil?

 

[Ron Burgundy]

The plug itself looks good (electrode and earth strap), the oily type deposit is the only thing that I find interesting on such a new engine. Does it use any oil?

No oil consumption issue. The usual couple hundred mil between services. Short trips maybe...
The plug is nit oily/wet. Just look like solid carbon buildup

 

[3rspecB]

@3rspecB, it is odd that your plugs are worn @ 47.5k kms yet the service life is 140k kms?
What was the reason you looked at the plugs so early in their life and what would be the cause of such an early demise?

I installed a new exhaust system, so safer to remove the plugs then to drop extractors on them which will generally brake them.

My car is not stock, i.e intake/exhaust/tune already done prior to install of new exhaust system. Most likely I'd say tune related but not fussed that they didn't last 140k.
They are cheap to buy and very easy to replace.

 

[gossie]

Gap them properly rather than a guess

 

[vr304]

Gap them properly rather than a guess

Exactly mate you’d have to have a pretty sharp eye to be able to tell how big the gap is just by looking at them

 

[Ron Burgundy]

I only took 1 out to check. I am not replacing them yet.

These acdelco plugs are pre gapped to 1mm from the factory.
I checked this with new set.

I will not be stuffing with removing them all just to check the gaps which would have been correctly gapped when new anyway.

 

[panhead]

I only took 1 out to check. I am not replacing them yet.

These acdelco plugs are pre gapped to 1mm from the factory.
I checked this with new set.

I will not be stuffing with removing them all just to check the gaps which would have been correctly gapped when new anyway.

Come on Ron you know you want to be sure the factory wasn't having a bad day.





.

 

[Skylarking]

I installed a new exhaust system, so safer to remove the plugs then to drop extractors on them which will generally brake them.

Better safe than sorry so good thinking Oh and I like the sound of the exhaust

My car is not stock, i.e intake/exhaust/tune already done prior to install of new exhaust system. Most likely I'd say tune related but not fussed that they didn't last 140k.
They are cheap to buy and very easy to replace.

May be something to discuss with the tuner if you are considering a retune for the different exhaust/header you’ve recently installed. And if your tuner thinks the plug life is ok, you then know how frequently to change them

 

[07GTS]

found this on another forum if it helps