Macbeast
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| posted on 12/6/08 at 07:57 AM |
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Do spark plugs disintegrate?
A friend left her Fiesta for MOT and service. Garage says on way back from MOT the centre electrode of a spark plug fell into the cylinder and damaged
piston and valves.
His story sounds reasonable to me but has anyone ever heard of a spark plug falling apart like this ?
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eznfrank
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| posted on 12/6/08 at 08:18 AM |
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When were they last replaced?? Overtightened?
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phoenix70
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| posted on 12/6/08 at 08:19 AM |
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That a new one on me, but I'm no expert. I would have thought it more likely it dropped a valve that damaged the piston and the spark plug
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nick205
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| posted on 12/6/08 at 08:27 AM |
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yes they can break up. if the engine wasn't runnin right or the plugs were very old or overtightened they will have a hard time and eventually
give up.
Removing the offending plug and if necessary the cylinder head will soon confirm what's happened.
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BenB
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| posted on 12/6/08 at 08:45 AM |
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Yup. They can...... But you'ld expect to notice the difference when it happened.....
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Davey D
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| posted on 12/6/08 at 09:34 AM |
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if the car is running lean ( hot ) then it is Very possible for the electrode to melt, and drop onto the cylinder...
.. although you normally hear about things like that happening on a poorly tuned turbo'd car that is suffering from Pre-Detonation
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britishtrident
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| posted on 12/6/08 at 09:34 AM |
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Not impossible especially if the engine has run very hot or lean but usually they go the other way -- I have seen a Hitachi plug where the complete
insulator was blown out cleanly and was found hanging on the end of the plug lead.
[Edited on 12/6/08 by britishtrident]
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Macbeast
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| posted on 13/6/08 at 08:27 AM |
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Oh well - apparently garage is charging about £300 to replace valves and piston so reasonable result.
I'm still puzzled how centre electrode could break up and drop past the side elecrtode unless the latter had completely burned away. But thanks
for comments anyway.
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