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about two weeks ago my car`s engine started to make a rattling noise.As I was in the middle of a roadworks with no possibility of stopping I carried on driving at a slow pace(approx.2k revs.)After about 3/4 mile the rattling stopped,I drove on gently,checking oil and temp.dials.Both normal. I took the car to nearest Fiat agent who diagnosed a faulty spark plug.Apparently the central electrode had dropped out of it and had been rattling about inside the cylinder.After replacing this plug,the car was running as well as ever.It has since covered over 500mls.with no apparent ill effects.Does anyone know if this happy state of affairs is likley to continue,or are the long term risk of scoring etc.too great and i should flog the car before damage becomes apparent? Anyone out there had a similar experience?
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During my City & Guilds day release college course, I was shown an early Ford Cortina piston which had been severely pock marked by a small ball bearing from the carburettor, also ruining the bores. The mechanic working on that car thought he would get away with it! He tried to just fit a new ball bearing in the carburettor. Those who have worked on the Fords of that era will know exactly which ball bearing I mean. It is exposed as soon as you take the lid off the carburettor! IIRC, it is a non-return valve for the accelerator pump, but this is besides the point!
My suggestion is that you have a look though a bore scope, or endoscope, via the spark plug hole, and see if there is any significant damage.
Your course of action upon seeing the extent of any damage is something that must be squared with your own conscience!
Number_Cruncher
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Did the Fiat dealer change the plug or just diagnose the fault? If he changed the plug then the broken electrode was probably retrieved by him but you need to ask! If you did then as NC says you need to take further action. If that bit of electrode gets jammed between the piston and the bore or between a valve and its seat then you will have damage occuring.
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Did they just replace the duff plug, or the whole set? If just the one, you should think about replacing the others, just so you know where you are when it comes to replacement time!
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If there is engine damage, you should check the plug as it may have been faulty manufacture. If it is get an independent view..
Champion replaced the engine in a V12 XJE that a colleague owned in 1975 after the central electrode collapsed and holed a piston resulting in a dead engine (at around 5,000rpm). It was examined by an engineer who stated a manufacturing fault. Chapion eventualy admitted liability (at a cost of several £000s then!)
madf
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Good point sprice!I was thinking the same thing myself,trouble is Halfords only sell plugs in packs of four so it will have to wait untill I can get down to Fiat,or find someone who sells them singly.He should really have changed the other four.(It`s a five pot) I think I will also go the endoscope route ASAP.
My own feeling(and the mechanic`s)is that it was small enough to be expelled through one of the exhaust valves.Car still seems to run as sweet as a nut.
By the way,if I did sell it,I would PX it,then the next owner would have the selling garage`s warranty to fall back on.Thank you all for helping.
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When this happened to me many years ago on a bike, the 'autopsy' was that something else had got in the cylinder and chipped the bit off the plug insulation rather than the plug failing first.
Mine was a rattle that stopped when the bit(s) were blown out of the exhaust. Top of the piston and alloy head were a bit of a mess, but after a little dressing went back fine.
Martin
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RE: "If he changed the plug then the broken electrode was probably retrieved by him but you need to ask!"
If it wasn't then the engine will still be making a rattling noise.
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Not if it's already got wedged/stuck somewhere. I would still ask.
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My Cavalier developed a misfire which proved to be caused by a small part of the ceramic insulator breaking off the NGK plug near the tip and causing the plug to fail. I was worried the insulator material might have damaged the bore but several thousand miles later no problems are apparent. I assume the piece of insulator was blown out of the exhaust. Is the insulator material on its own too soft to damage the bore? The ceramic insulator can crack and subsequently fail by the plug being dropped onto a hard surface before the spark plug is first fitted.
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Victorbox - the insulator is usually a ceramic material and extremely hard but brittle. I suspect it may get beaten to powder fairly quickly end ejected. My bike showed dings in the head and piston crown from the debris, but no excessive bore wear.
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