Author Topic: Do these plugs look OK?  (Read 472 times)

Offline andrewrx7

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Do these plugs look OK?
« on: April 19, 2006, 10:39:29 PM »
Just changed the spark plugs - do the old plugs look OK? The pic below shows
top left = rear rotor, leading (plug is a 7)
top right = rear rotor, trailing (plug is a 9)
bottom left = front rotor, leading (plug is a 7)
bottom right = front rotor, trailing (plug is a 9)

Notes on the pics: the front rotor has that classic tan colour which we\'re taught is a sign of a good mixture. Is this still true for the rotary? The rear plugs are a little blacker (running slightly rich? - a good sign?)
The plug on the top right does not have a chunk missing, some of the carbon on the surface just flaked off!
And they all have a circular wear pattern, presumably where the spark has eroded the 4 outer electrodes - again, is this normal? Plugs are 3k mile old, by the way.

(The car is std (inc ecu), and run on Optimax).

Cheers!

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Do these plugs look OK?
« Reply #1 on: April 20, 2006, 03:00:42 AM »
Colour does not look bad and its best to have the rears slightly richer (cooler) than the fronts, because of the extra heat on the rear rotor

John Yorke

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Do these plugs look OK?
« Reply #2 on: April 20, 2006, 07:11:41 AM »
As an extra safety measure it might be worth having your injectors cleaned and flow rated, generaly you should have matching pairs - both leading the same colour as well as matching trailing. Tan brown looks about right though.

Offline clive

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Do these plugs look OK?
« Reply #3 on: April 20, 2006, 08:57:21 AM »
Don\'t worry Andrew there is no way I can see the colour disparity between the two Rotors being enough to worry about indeed I think the colours look good, normally you find plugs that have been running a much weaker mixture than your car when they are stock.

I would say, If it aint broke don\'t fix it .

BTW, sorry I have drawn a blank finding more spec on your car for you.
« Last Edit: April 20, 2006, 09:01:37 AM by clive »
All the best Clive