Very strange spark plug event

[Nightsoil]

:?:

Just replaced the spark plugs on my 300E 24V.. using Berus.. set gaps on all the plugs and fitted. Started engine to find it missing every second or so..


Pulled all the plugs out and found #5 spark plug with a zero gap :?: :?:

No if I had dropped the plug I would have remembered and reset gap - nope just popped it in like the others. I checked the plug to make sure it wasn't faulty i.e. the "arm" had broken - all fine.

Refitted plug and car is 100% perfect..

Any ideas on what might have happened - 'cos I haven't

 

[OlafMaxwell]

Not sure about that one. I am sure there are gremlins working in there closing the gap just to play games with you.

A more realistic one....just occasionally you can get a dud plug but extremely rare. Dont want it disintegrating inside the cylinder. Anyway you have already checked that one.

Is it possible [I know, just me] washer was missing or plugs were right thread but too long? The clearances betwen plugs and either valves or pistons is very minimal. I cannot think of anything inside cylinder to do it. Any valve troubles?

I must admit I would be still more likely to think as it was being inserted a knock against the head closed the gap.

 

[Nightsoil]

Yup I agree that I probably knocked it somehow without knowing.

I have been driving the car over the past few days right up to the red line - pulled out plugs and everything is fine.. I'm sure that if it was an in-cylinder impact it would have done it again..

Thanks

Adam