Probably a dumba$$ question
I have started work on the engine and wonder if these plugs are OK or look like they need replacing-





Thanks

 

If you already have them out I'd put in new ones, you already did all the work

 

Jaguar recommends sparking plug replacement at 100,000 miles for a Normally Aspirated AJV8 engine.

It's your car, do what you think is necessary.

bob gauff

 

I have no idea if these are original, although the car has now done over 140k so I would expect originals to be more worn than that.
I have just removed one plug to see the condition but don't want to spend money unnecessarily.
Could someone make a judgement based on the appearance?

 

It looks fine. Adjust the gap if required and off you go.

 

This. I pulled my original NGK Iridiums at 131k several months ago and they looked about like that. If you're at around that mileage and they haven't been done before, just do it.

 

Denso and NGK iridium plugs will easily do 200,000 miles if the car is properly maintained. There are reports of them doing 300,000 miles and still looking nearly new in the best of circumstances. The one plug you posted a photo of looks just fine to me....

 

Mine had 63k of use and were the original Iridium factory fit, I kept them and cleaned them with a wire brush, they looked like new apart from the heat ring on the insulator similar to your picture. If your budget is tight, and the car is running as expected, take them all our clean them and gap them, then make the judgement, they may not all be the same.
By the way my replacements were Platinum, ordered by mistake, should have gone for Iridium, however not noticed ANY difference in performance or fuel consumption, think Platinum do not last as long as they wear quicker.

 

It is pure fantasy of marketing departments when discussion of performance or fuel consumption comes up. The spark either ignites the air/fuel mixture in the vicinity of the electrodes, or it doesn't. There is no 'in between'. Even the cheapest conventional plug will do a perfect job, it just won't last as long.