Spark plug slightly loose.... piston holed??
 

Hi.
A discussion elsewhere has got a little heated!!!! Does anyone know if a plug that has not been tightened enough to flatten the sealing washer would cause the plug to overheat and hole a piston??
Not my car incidentally.

No, it happened to me on a previous Rover 75, all that was required was to fit a helicoil in the plug thread and a new plug, the car ran perfectly after that for many thousands of miles

That wouldn't cause it, the old v8 rover engine used to loosen plugs all the time!

It would never make a hole in the piston.

I have heard of melted plugs that have holes pistons.

There is a twist thought. Cheapie eBay plugs. All branded beautifully but dangerous fakes - the cores being made from iron and not copper. Took out a friend's motorbike.

Thanks chaps.
The point raised was if the sealing washer wasn't flattened correctly it would not allow the plug to cool and thus raise the tip temperatures, this would cause pre ignition and hole a piston. The car was a 3 pot unit. My feeling is a modem unit is less likely to suffer with pre ignition due to the timing of the fuel injectors and knock sensor, I've come across many loose plugs but never this, even on tuned rally cars.